money.amount
A currency-tagged monetary amount held in integer minor units.
Organisations / anterra
Anterra
Money, tax and invoicing capabilities for UK and Irish business software.
Published functions 200
finance.tax.vat-rate Unreviewed
Look up the VAT rate in force for a jurisdiction, category and date.
construction.payment-notice-dates
Construction Act default dates: payment due, payment notice, final date for payment and pay-less notice.
insurance.ipt Unreviewed
UK Insurance Premium Tax at the standard or higher rate in force on a date, added to or taken out of a premium.
payroll.student-loan Unreviewed
Student loan or postgraduate loan deduction from one period's pay, by plan, rounded down to whole pounds.
charity.gift-aid-eligibility
Whether a UK donation qualifies for Gift Aid: declaration, enough tax paid, and the donor benefit limits.
fleet.tachograph-rest Unreviewed
Check daily and weekly rest against GB/EU drivers' hours: 11h daily (9h reduced, 3+9 split), 45h weekly (24h reduced).
construction.cis-deduction
Construction Industry Scheme deduction (0, 20 or 30%) on the labour part of a subcontractor payment.
finance.tax.remove-vat Unreviewed
Extract the VAT already included in a gross amount, using the rate in force on the date of supply.
health.gestational-age Unreviewed
Gestational age (weeks+days) and estimated due date from the last menstrual period by Naegele's rule, cycle-adjusted.
insurance.sum-insured-average Unreviewed
Average clause settlement for underinsurance: the loss times sum insured over value at risk, capped at the loss.
invest.section-104-pool Unreviewed
UK share matching for CGT: same-day, 30-day bed-and-breakfast, then the Section 104 pool; allowable cost per disposal.
validation.uk-postcode
Validate a UK postcode and normalise it to canonical upper case with one space before the inward code.
charts.extent
The minimum and maximum of a series as [min, max], skipping gaps (null), or null when there is no value.
charts.scale
Map data values onto screen positions and back: linear, log, time, band and point scales, and nice domains.
charts.shape
SVG path strings for lines, areas, steps, monotone curves, bars, arcs and pie slices, identical in every language.
energy.price-cap
Ofgem energy price cap unit rate and daily standing charge for a fuel and payment method on a date (GB average).
finance.invoice.calculate
Calculate a complete invoice: line nets, VAT per line, totals and a VAT summary grouped by rate.
finance.tax.add-vat Unreviewed
Add VAT to a net amount using the rate in force on the date of supply.
finance.uk-bank-rate
Bank of England Bank Rate (base rate) in force on a date, from the Bank's official history since 2001.
health.waiting-time Unreviewed
NHS England referral-to-treatment (RTT) wait in days and weekly bands, with the 18-week breach flag.
lending.overpayment-effect Unreviewed
What a one-off overpayment does to a loan: a shorter term at the same payment, or a lower payment over the same term.
math.exp
e to the power x from + - * / only, so TypeScript, Python and Rust return the same double for the same input.
math.sin-cos
Sine and cosine of an angle in radians from + - * / only, so every language returns the same doubles.
payroll.minimum-wage-check Unreviewed
Check pay for a pay reference period against the minimum or living wage for age and apprenticeship.
payroll.national-insurance Unreviewed
Employee and employer Class 1 National Insurance for one payment by category letter, exact percentage method.
payroll.overtime Unreviewed
Pay for the time worked in a period split into multiplier bands: basic, time and a half after 40 hours, double time.
property.mortgage-affordability Unreviewed
Mortgage affordability: the loan-to-income multiple and a stress-tested repayment against income, both checked.
retail.oss-vat
EU distance-selling VAT: which member state's standard rate applies under OSS and the EUR 10,000 threshold, and the VAT.
stats.moving-average
Simple or exponential moving average over a series, one value per full window, rounded to stated decimals.
subscriptions.mrr-arr
Monthly and annual recurring revenue from a list of subscriptions, normalising intervals and leaving out trials.
todo.group-by-due
Split todos into Overdue, Today, Tomorrow, This week, Later, No date and Done sections, in that order.
banking.faster-payments-limit
Whether a Faster Payment fits the scheme maximum, the bank's per-payment limit and what is left of its daily limit.
charity.gift-aid
Gift Aid a UK charity can claim on a donation: basic rate tax grossed up, 25p per £1 at 20%.
charity.reclaim-batch
Gift Aid claim totals for a period from donation records: donor lines, aggregated small gifts, tax due.
education.academic-year
The academic year and term a date falls in: 1 September to 31 August by default, terms from the caller.
form.date-parts
Check a date typed into day, month and year boxes, with GOV.UK's error messages and the boxes to mark in error.
hospitality.bill-split
Split a restaurant bill evenly, by item or by share, exactly to the penny, with the service charge shared in proportion.
insurance.excess-apply Unreviewed
Claim payout after the compulsory and voluntary excess, capped at the policy limit.
invest.drawdown-sustainability Unreviewed
How many years a pension or investment pot lasts under a yearly withdrawal and a constant growth rate, year by year.
legal.disbursements-vat Unreviewed
Whether a cost passed to a client is a VAT disbursement (outside scope) or a recharge (VAT due), per HMRC Notice 700.
logistics.freight-rate
Freight charge from a carrier's dated weight-break tariff for a zone, with the fuel surcharge in force on the ship date.
logistics.sscc
Build an 18-digit SSCC pallet label number from extension digit, GS1 company prefix and serial, with its check digit.
math.rational
Exact fraction arithmetic, always reduced, for rates and ratios that must not drift.
money.add
Add, subtract and negate monetary amounts, refusing to mix currencies.
money.split-even
Split an amount into n near-equal parts that add back up to exactly the whole.
property.completion-statement Unreviewed
A buyer's completion statement: price less deposit, ground rent and service charge apportioned to completion, plus fees.
retail.coupon-validate
Check a coupon against a basket: dates, usage limits, eligible products and minimum spend, with reason codes.
retail.shipping-rate
Delivery charge from a dated rate table by service, zone, chargeable weight and size, with a free-over threshold.
stats.percentile
Percentile of a list of numbers by a named method: nearest-rank, or linear interpolation (R-7, Excel PERCENTILE.INC).
validation.uk-company-number
Check a Companies House company number's format and prefix (SC, NI, OC, LP...) and zero-pad it to eight characters.
validation.uk-utr
Check an HMRC Unique Taxpayer Reference's modulus 11 check digit, accepting the K and spacing people type.
charts.color
Hex colours to RGB and back, and sRGB channels to linear light and back, identically in every language.
energy.carbon-emissions
kgCO2e from kWh or litres of a fuel, using the UK government GHG conversion factors for the year.
finance.proration
Split an amount into the part used and the part unused over a billing period, losing nothing.
fleet.emissions
Vehicle greenhouse gas emissions (grams CO2e) from fuel used or distance, using UK government DESNZ conversion factors.
fleet.mileage-allowance
HMRC approved mileage allowance payments for an employee's own vehicle: tax-free amount, taxable excess or relief.
geo.distance
Great-circle distance in metres between two latitude/longitude points (haversine), to the millimetre.
health.bmi Unreviewed
Adult body mass index (kg/m², 1 decimal place) and its NICE/WHO weight category.
health.bsa Unreviewed
Body surface area in m² by the Mosteller and the DuBois & DuBois formulas, to 2 decimal places.
health.egfr Unreviewed
eGFR in mL/min/1.73 m² by the race-free CKD-EPI 2021 creatinine equation, from creatinine in µmol/L or mg/dL.
insurance.premium-proration Unreviewed
Return premium on mid-term cancellation, pro rata or on a short-period scale, with an optional minimum retained premium.
insurance.rating-factors Unreviewed
Premium from a base rate times factor-table lookups, loadings and discounts, within minimum and maximum premiums.
invest.cagr Unreviewed
Compound annual growth rate between two values over a whole or fractional number of years, in basis points.
invest.fee-drag Unreviewed
What an annual charge costs an investment over the years: value with and without the fee, year by year, in minor units.
lending.early-settlement Unreviewed
Early settlement figure and rebate on UK regulated consumer credit, per the Early Settlement Regulations 2004.
money.compare
Compare two amounts of one currency, refusing to compare across currencies; min, max and clamp too.
monitor.burn-rate-alert
Multiwindow, multi-burn-rate SLO alerting: which rules fire, from event counts per window (Google SRE workbook).
payroll.income-tax Unreviewed
PAYE income tax for one pay period from a tax code, cumulative or week 1/month 1, by HMRC's tax table routines.
payroll.net-to-gross Unreviewed
The gross pay that gives at least a target net pay in one UK pay period, found by a deterministic search.
payroll.statutory-sick-pay Unreviewed
UK Statutory Sick Pay for sickness spells: waiting days, 8-week linking, 28-week limit and the rate by date.
property.rent-proration Unreviewed
Rent for part of a month from the monthly rent, by the annual-daily or the calendar-month method.
property.service-charge-apportion Unreviewed
Apportion a service charge across units by lease fraction, floor area or fixed percentage, exact to the penny.
telecoms.roaming-charge
Roaming charges for a trip abroad from a dated tariff table of zones: daily fees, data, calls and texts.
validation.nhs-number
Check an NHS number's modulus 11 check digit and normalise it to ten digits.
agri.feed-ration
Ration costing and dry matter intake from each feed's fresh weight, DM % and price per tonne, in exact money.
agri.fertiliser-application
Fertiliser product rate (kg/ha and total) to meet N, P2O5 and K2O targets from its analysis, limiting nutrient first.
agri.field-area
Field area in square metres, hectares and acres from a boundary polygon of latitude/longitude points.
agri.gross-margin
Enterprise gross margin (output less variable costs), in total and per hectare or per head, in exact money.
auth.access-token
Issue an API's HS256 access token, read one from an Authorization header, and refuse revoked or superseded ones.
auth.jwt
Sign, verify and decode HS256 JSON Web Tokens (RFC 7519): signature, algorithm and exp/nbf/iat checked with leeway.
auth.validate-password-change
Check a change-password form: current password given and correct, new one meeting the policy and different.
auth.validate-registration
Validate a sign-up form (email, password, name) in one call, with a message per field, in the browser and the API alike.
banking.overdraft-interest
Overdraft interest for a statement period from daily balances, with an interest-free buffer.
charity.gasds
Gift Aid Small Donations Scheme top-up for a tax year: the £8,000 limit, the matching rule and community buildings.
charity.payroll-giving
UK Payroll Giving for one pay period: the donation comes off pay before PAYE, and the tax it saves the employee.
charity.regular-giving-schedule
Collection dates for a regular gift: monthly, quarterly or annual on a day, clamped to short months, after a lead time.
charity.restricted-funds
Allocate charity spending to restricted funds first, then unrestricted funds, never overdrawing a restricted fund.
charts.bar-chart
Complete bar chart geometry as data, grouped or stacked: plot area, axes, gridlines, bar rectangles, colours, legend.
charts.downsample
Reduce a long series to a few points that keep its visual shape, by Largest-Triangle-Three-Buckets (LTTB).
charts.format
Axis and label text for charts: tick numbers, SI prefixes (1.2k, 3.4M), percentages, dates and money.
charts.histogram-bins
Bin values into histogram bins on round edges, by Sturges' rule, Freedman-Diaconis, or a fixed width.
charts.interpolate-color
The colour at a point along a sequential or diverging ramp, mixed in OKLab so steps look even; hex in, hex out.
charts.line-chart
Complete line chart geometry as data: plot area, number or date axes, gridlines, series paths, colours, legend.
charts.palette
A categorical palette of n colour-blind-safe colours for chart series: Okabe-Ito or Paul Tol's bright scheme.
charts.stack
Stack several series for stacked bars and areas: on zero, normalised to 100%, or diverging around zero.
collections.chunk
Split a list into consecutive batches of at most n items, in order; the last batch may be short.
collections.dedupe-by-key
Remove records that share a key value, keeping the first or the last of each, in input order.
collections.diff
Compare two lists of records by key: which were added, which removed, and which changed and in what fields.
collections.group-by-key
Group records by the value at one key, preserving input order inside each group.
collections.paginate
Slice a list into a 1-based page and report the totals an API response needs.
collections.sort-by
Stably sort records by one key, ascending or descending, with a total order across mixed types.
construction.brick-count
Bricks and mortar for a wall, openings subtracted, for UK standard 215 x 102.5 x 65 mm bricks with 10 mm joints.
construction.concrete-volume
Concrete for slabs, strip footings, pads and round columns: volume to the litre and an order rounded up to 0.1 m³.
construction.materials-area
Packs of tiles, paint, plasterboard or flooring to cover an area, with waste and coats, rounded up to whole packs.
construction.retention
Retention held and released on a construction valuation: full rate, half at practical completion, none at the end.
construction.roof-pitch
Roof pitch in degrees, rafter length and roof slope area from span, rise and length.
crypto.constant-time-equal
Compare two byte strings in time that does not depend on where they differ, for checking MACs and hashes.
crypto.hmac-sha256
HMAC-SHA256 of a message under a secret key (RFC 2104, RFC 4231), in pure code that also runs in the browser.
crypto.sha256
The SHA-256 digest of a byte string (FIPS 180-4), in pure code that also runs in the browser.
dates.age
Age in whole years on a given date, with 29 February birthdays ageing on 1 March in other years.
dates.overlap
Days two date ranges have in common, with the end of each range stated as inclusive or exclusive.
dates.quarter
Calendar quarter and fiscal quarter of a date, with the fiscal year and quarter date ranges, for any start month.
dates.uk-tax-year
The UK personal tax year containing a date: 6 April to 5 April, with HMRC's label.
education.attendance-rate
Pupil attendance and absence rates in basis points, with the DfE persistent and severe absence flags.
education.degree-classification
UK honours degree class (First, 2:1, 2:2, Third) from module marks and credits, weighted by level.
education.student-loan-repayment
A graduate's student or postgraduate loan repayment for a tax year, as Self Assessment works it out.
education.timetable-clash
Find timetable clashes: overlapping sessions that share a room, a teacher or a student group, in a fixed order.
encoding.hex
Bytes to lowercase hexadecimal text and back (RFC 4648 base16), strictly, identically in every language.
encoding.utf8
Text to UTF-8 bytes and strictly back (RFC 3629), so hashing and signing see the same bytes in every language.
energy.degree-days
Heating and cooling degree days from daily mean temperatures and a base temperature, exact to 0.1.
energy.estimate-read
Estimate a meter read for a date from the average daily consumption between two earlier reads, with rollover.
energy.meter-advance
Units consumed between two meter reads, counting the meter rolling over past all nines once.
energy.tariff-time-of-use
Cost half-hourly consumption against time-of-use rates: Economy 7 windows or Agile-style half-hourly prices.
energy.water-bill
Metered water and sewerage bill from two reads: volumetric charges, return to sewer, standing and surface water charges.
finance.credit-note.calculate
Credit note against an original invoice, by units or by amount, with VAT at the original tax point's rates.
finance.fx-revaluation
Unrealised foreign exchange gain or loss on foreign-currency balances revalued at a period-end rate.
finance.late-payment-interest
UK statutory late payment interest (8% over Bank Rate) and fixed compensation under the Late Payment Act 1998.
finance.ledger.journal-validate
Check a double-entry journal: debits equal credits, no zero or two-sided lines, one currency, well-formed account codes.
finance.payment-terms-due-date
Invoice due date from payment terms: net N days, end of month, N days after month end, day N of next month.
finance.tax.vat-flat-rate Unreviewed
UK VAT Flat Rate Scheme: VAT due on gross turnover at the sector's dated rate, limited cost rate and first-year 1% off.
finance.tax.vat-return Unreviewed
UK nine-box VAT return totals for a period from categorised sales and purchases (VAT Notice 700/12).
fleet.ev-charging-cost
Cost of an electric vehicle charge from the energy added, charger efficiency and power, and time-of-use tariff windows.
fleet.fuel-cost
Fuel cost of a trip from distance, fuel economy (UK or US mpg, or L/100km) and price per litre, exactly.
fleet.vehicle-depreciation
A vehicle's current value from its cost, age and mileage, on retention curves the caller supplies, exactly.
geo.point-in-polygon
Whether a latitude/longitude point lies inside a polygon (ray casting; the boundary counts as inside).
health.dose-weight-based Unreviewed
Weight-based dose (per kg) capped at a maximum single dose and rounded to a measurable volume, in exact micro-units.
hospitality.allergen-matrix Unreviewed
Which of the 14 UK major allergens a dish contains or may contain, from its ingredients' declared allergens.
hospitality.recipe-cost
Cost a recipe and each portion from ingredient quantities, pack sizes and pack prices, allowing for trim and waste.
hospitality.tourist-tax
Visitor levy (tourist tax) on an overnight stay: Edinburgh's 5%, Cardiff's per person per night, or a caller's own rule.
hr.absence-bradford-factor
Bradford factor for a set of absence spells: spells squared times total days, which weights frequent short absences.
http.retry-after
Seconds to wait from an HTTP Retry-After header (delay-seconds or an HTTP date), or null if missing or malformed.
insurance.claim-reserve Unreviewed
Claim reserve history: paid, recovered, outstanding and incurred after each transaction, and the movement.
insurance.loss-ratio Unreviewed
Loss ratio, expense ratio and combined ratio in basis points, from earned premium, incurred claims and expenses.
insurance.no-claims-discount Unreviewed
No-claims discount at renewal: earn a year, or step back after claims on the insurer's scale, with NCD protection.
inventory.abc-classification
ABC classes by annual consumption value (Pareto), with configurable cut-offs such as 80/15/5 and deterministic ties.
inventory.reorder-point
Reorder point: demand over the supplier lead time, rounded up to whole units, plus safety stock.
invest.bond-yield Unreviewed
Current yield and yield to maturity of a fixed-coupon bond from its clean price, as Excel's YIELD defines it.
invest.capital-gains-tax Unreviewed
UK Capital Gains Tax for an individual's tax year: losses, annual exempt amount, and the rates by asset and date.
invest.pension-annual-allowance Unreviewed
UK pension annual allowance for a tax year with taper, MPAA and three-year carry-forward, and the excess charged.
invest.rebalance Unreviewed
Whole-unit buy and sell trades that bring a portfolio back to target weights, skipping trades below a minimum size.
legal.retainer-drawdown Unreviewed
Apply money held on account in client account to bills in order: what each bill takes, what stays due, what is left.
legal.time-billing Unreviewed
Fees from time entries: each rounded to 6-minute (or other) units and priced at the fee earner's hourly rate.
lending.affordability Unreviewed
Debt-to-income and a stressed-rate affordability test for a proposed loan's monthly repayment.
lending.amortisation-schedule Unreviewed
Repayment schedule for a level-payment loan: interest, principal and balance per period, ending at exactly zero.
lending.apr Unreviewed
Consumer-credit APR from drawdowns and repayments, by the FCA CONC App 1.2.6 equation, to one decimal place.
lending.loan-payment Unreviewed
Level repayment for a loan (annuity formula), computed exactly and rounded once, the way you choose.
logistics.route-distance
Total great-circle distance of an ordered list of stops, leg by leg, optionally back to the start, to the millimetre.
manufacturing.batch-size
Economic batch quantity: the EOQ for a batch made at a finite production rate, in whole units.
manufacturing.variance
Standard costing variances: material price and usage, labour rate and efficiency, favourable or adverse.
manufacturing.yield-scrap
Whole units to start for a required good output at a process yield, and the scrap that allows for.
math.basis-points
Convert a rate between percent, basis points and a plain ratio exactly, as decimal text or integer basis points.
math.clamp
Clamp an integer to an inclusive range, refusing a range whose bounds are the wrong way round.
math.integer-sqrt
Exact integer square root: the largest whole number whose square does not exceed n.
math.pow
base to the power exponent from + - * / only, exact by squaring for whole exponents, identical in every language.
math.round-div
Integer division with an explicit rounding mode, for money arithmetic that must not drift.
math.round-float
Round a float half away from zero to 0-12 decimal places, identically in TypeScript, Python and Rust.
money.allocate
Split an amount across ratios without losing or inventing a single minor unit.
money.apply-rate
Apply a rate expressed in basis points to a monetary amount, with an explicit rounding mode.
money.convert
Convert an amount to another currency at a supplied exact rate, with an explicit rounding mode.
money.parse
Parse "£1,234.50" or "1.234,50 €" into integer minor units, strictly: no guessing, no rounding.
monitor.burn-rate
How fast an SLO's error budget is burning: the error rate as a multiple of the rate the SLO allows, in thousandths.
monitor.cert-expiry
How long a TLS certificate has left before its notAfter, and whether that is ok, a warning, critical or expired.
monitor.error-budget
How much of an SLO's error budget is allowed, used and left, from good and bad event counts or seconds.
monitor.mttr
MTTR, MTBF, downtime and incident counts for a reporting window, from a list of incidents.
monitor.rollup
Aggregate a metric series into fixed time buckets (count, min, max, avg, sum, last), empty buckets included.
monitor.series-window
The samples of a time series from one moment up to (not including) another, checking they are in time order.
monitor.status-code-summary
Count HTTP status codes by class (1xx to 5xx) and give the server error and client error rates in basis points.
net.cidr
CIDR blocks: network, broadcast, first and last host, host count, netmask and prefix, and membership.
net.ip-classify
Classify an IPv4 or IPv6 address as loopback, private, link-local, multicast, documentation, CGNAT or global.
net.ipv4
Parse, format and check dotted-quad IPv4 addresses, refusing leading zeros, octal, hex and short forms.
net.ipv6
Parse IPv6 addresses and write them in RFC 5952 canonical form: lower-case, zeros compressed, IPv4 embedded.
net.mac-address
Validate a MAC address in colon, hyphen, Cisco dot or bare form and normalise it, with multicast and local bits.
net.port
Check a TCP/UDP port number and name the IANA service registered on it, with its system/user/dynamic range.
payroll.gross-to-net Unreviewed
A UK payslip for one pay period: gross pay, pension, PAYE tax, National Insurance, student loans and net pay.
payroll.notice-period Unreviewed
Statutory minimum notice in weeks from continuous service: one week per year from two years, capped at twelve.
payroll.tax-code-parse Unreviewed
Parse a UK PAYE tax code (1257L, K475, BR, D0, NT, 0T, S and C prefixes, W1/M1/X) into its allowance and flags.
payroll.tax-period Unreviewed
The UK PAYE tax week, tax month and payroll period number that a pay date falls in, weeks 53, 54 and 56 included.
professional.utilisation
Billable utilisation and billing, collection and overall realisation rates, in basis points.
property.council-tax-band Unreviewed
Council tax for a valuation band from the Band D charge: the statutory band ratio, England, Wales and Scotland.
property.floor-area Unreviewed
Floor area from room lengths and widths, exactly, with the total in both square metres and square feet.
property.rental-yield Unreviewed
Gross and net rental yield of a let property, in basis points, from annual rent, costs and value.
react.form.button React ^19 · TypeScript only
A form button in primary, secondary or warning style that stays focusable while loading (GOV.UK button).
react.form.fieldset React ^19 · TypeScript only
Group related inputs under a legend, with a hint and error message described to the whole group (GOV.UK fieldset).
react.form.form-field React ^19 · TypeScript only
Wire a label, hint and error message to one form control by id, the accessible way (GOV.UK form group pattern).
react.form.styles React ^19 · TypeScript only
An optional stylesheet for the react.form elements' caps-* classes, themed by --caps-form-* custom properties.
retail.basket-total
Total a basket: line prices, promotions, a basket discount, VAT per line and delivery, into one checked total.
retail.loyalty-points
Loyalty points for a purchase: redeem in blocks, earn on what is paid, with tier multipliers.
retail.promotion-apply
Apply BOGOF, 3-for-2, percent off, amount off and multibuy deals to a basket, best for the customer, allocated to lines.
retail.volumetric-weight
Chargeable parcel weight: the greater of actual and volumetric (dimensional) weight, rounded up to a billing step.