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.remove-vat Unreviewed
Extract the VAT already included in a gross amount, using the rate in force on the date of supply.
hospitality.bill-split
Split a restaurant bill evenly, by item or by share, exactly to the penny, with the service charge shared in proportion.
finance.proration
Split an amount into the part used and the part unused over a billing period, losing nothing.
insurance.sum-insured-average Unreviewed
Average clause settlement for underinsurance: the loss times sum insured over value at risk, capped at the loss.
money.split-even
Split an amount into n near-equal parts that add back up to exactly the whole.
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.
validation.uk-postcode
Validate a UK postcode and normalise it to canonical upper case with one space before the inward code.
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.
auth.access-token
Issue an API's HS256 access token, read one from an Authorization header, and refuse revoked or superseded ones.
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.
construction.retention
Retention held and released on a construction valuation: full rate, half at practical completion, none at the end.
crypto.constant-time-equal
Compare two byte strings in time that does not depend on where they differ, for checking MACs and hashes.
dates.quarter
Calendar quarter and fiscal quarter of a date, with the fiscal year and quarter date ranges, for any start month.
finance.tax.add-vat Unreviewed
Add VAT to a net amount using the rate in force on the date of supply.
geo.distance
Great-circle distance in metres between two latitude/longitude points (haversine), to the millimetre.
health.gestational-age Unreviewed
Gestational age (weeks+days) and estimated due date from the last menstrual period by Naegele's rule, cycle-adjusted.
hr.absence-bradford-factor
Bradford factor for a set of absence spells: spells squared times total days, which weights frequent short absences.
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.drawdown-sustainability Unreviewed
How many years a pension or investment pot lasts under a yearly withdrawal and a constant growth rate, year by year.
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.
money.parse
Parse "£1,234.50" or "1.234,50 €" into integer minor units, strictly: no guessing, no rounding.
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.
net.ipv4
Parse, format and check dotted-quad IPv4 addresses, refusing leading zeros, octal, hex and short forms.
professional.utilisation
Billable utilisation and billing, collection and overall realisation rates, in basis points.
property.mortgage-affordability Unreviewed
Mortgage affordability: the loan-to-income multiple and a stress-tested repayment against income, both checked.
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).
stats.moving-average
Simple or exponential moving average over a series, one value per full window, rounded to stated decimals.
validation.bic
Check the format of a SWIFT/BIC code (8 or 11 characters) and split it into its parts.
validation.iban
Check an IBAN against the ISO 13616 mod-97-10 checksum and the registered length for its country.
agri.gross-margin
Enterprise gross margin (output less variable costs), in total and per hectare or per head, in exact money.
charity.higher-rate-relief
A Gift Aid donor's extra tax relief at higher, intermediate, additional and top rates, by extending the tax bands.
charts.downsample
Reduce a long series to a few points that keep its visual shape, by Largest-Triangle-Three-Buckets (LTTB).
collections.sort-by
Stably sort records by one key, ascending or descending, with a total order across mixed types.
dates.age
Age in whole years on a given date, with 29 February birthdays ageing on 1 March in other years.
dates.uk-tax-year
The UK personal tax year containing a date: 6 April to 5 April, with HMRC's label.
education.timetable-clash
Find timetable clashes: overlapping sessions that share a room, a teacher or a student group, in a fixed order.
encoding.base64
Bytes to base64 and base64url text and back (RFC 4648), with strict decoding, identically in every language.
encoding.hex
Bytes to lowercase hexadecimal text and back (RFC 4648 base16), strictly, identically in every language.
energy.meter-advance
Units consumed between two meter reads, counting the meter rolling over past all nines once.
energy.price-cap
Ofgem energy price cap unit rate and daily standing charge for a fuel and payment method on a date (GB average).
energy.tariff-time-of-use
Cost half-hourly consumption against time-of-use rates: Economy 7 windows or Agile-style half-hourly prices.
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.invoice.calculate
Calculate a complete invoice: line nets, VAT per line, totals and a VAT summary grouped by rate.
finance.tax.vat-return Unreviewed
UK nine-box VAT return totals for a period from categorised sales and purchases (VAT Notice 700/12).
finance.uk-bank-rate
Bank of England Bank Rate (base rate) in force on a date, from the Bank's official history since 2001.
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.
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).
geo.point-in-polygon
Whether a latitude/longitude point lies inside a polygon (ray casting; the boundary counts as inside).
health.bsa Unreviewed
Body surface area in m² by the Mosteller and the DuBois & DuBois formulas, to 2 decimal places.
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.
health.waiting-time Unreviewed
NHS England referral-to-treatment (RTT) wait in days and weekly bands, with the 18-week breach flag.
hospitality.recipe-cost
Cost a recipe and each portion from ingredient quantities, pack sizes and pack prices, allowing for trim and waste.
inventory.abc-classification
ABC classes by annual consumption value (Pareto), with configurable cut-offs such as 80/15/5 and deterministic ties.
inventory.eoq
Economic order quantity (Harris/Wilson): the order size that minimises ordering plus holding cost, in whole units.
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.
invest.rebalance Unreviewed
Whole-unit buy and sell trades that bring a portfolio back to target weights, skipping trades below a minimum size.
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.
lending.apr Unreviewed
Consumer-credit APR from drawdowns and repayments, by the FCA CONC App 1.2.6 equation, to one decimal place.
math.clamp
Clamp an integer to an inclusive range, refusing a range whose bounds are the wrong way round.
math.exp
e to the power x from + - * / only, so TypeScript, Python and Rust return the same double for the same input.
math.integer-sqrt
Exact integer square root: the largest whole number whose square does not exceed n.
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.convert
Convert an amount to another currency at a supplied exact rate, with an explicit rounding mode.
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.uptime
Time-weighted uptime of a target over a window from its checks, with gaps longer than a limit counted as unknown.
net.ipv6
Parse IPv6 addresses and write them in RFC 5952 canonical form: lower-case, zeros compressed, IPv4 embedded.
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.student-loan Unreviewed
Student loan or postgraduate loan deduction from one period's pay, by plan, rounded down to whole pounds.
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.service-charge-apportion Unreviewed
Apportion a service charge across units by lease fraction, floor area or fixed percentage, exact to the penny.
telecoms.call-rating
Rate a call from a rate deck: longest-prefix destination match, billing increments, connection fee and minimum charge.
text.initials
Initials from a personal name for avatars and signatures: "Jean-Paul Sartre" is "JPS".
text.mask
Mask all but the last n characters of a card, account or phone number, optionally keeping separators.
todo.parse-date-phrase
Read a typed due date like "tomorrow", "next friday", "in 2 weeks" or "2026-10-01" as a date, relative to today.
validation.email
Is this a plausible email address? A documented, pragmatic subset of RFC 5322, not the full grammar.
validation.isbn
Check an ISBN-10 or ISBN-13 and convert between them; the normalised form is always the ISBN-13.
validation.lei
Check a 20-character Legal Entity Identifier against its ISO 17442 / ISO 7064 MOD 97-10 check digits.
validation.vin
Check a 17-character vehicle identification number and its check digit; enforced for North American VINs.
agri.spray-mix Unreviewed
Sprayer tank mix: tank fills, and product and water per full and part tank, for an area, water volume and dose.
agri.yield-per-hectare
Crop yield per hectare and per acre from harvested quantity and field area in any area unit, exactly, as decimal text.
auth.jwt
Sign, verify and decode HS256 JSON Web Tokens (RFC 7519): signature, algorithm and exp/nbf/iat checked with leeway.
banking.fees-cap
Apply a monthly fee cap to a list of account charges: charge up to the cap, waive the rest.
charity.gasds
Gift Aid Small Donations Scheme top-up for a tax year: the £8,000 limit, the matching rule and community buildings.
charity.reclaim-batch
Gift Aid claim totals for a period from donation records: donor lines, aggregated small gifts, tax due.
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.
charts.bar-chart
Complete bar chart geometry as data, grouped or stacked: plot area, axes, gridlines, bar rectangles, colours, legend.
charts.format
Axis and label text for charts: tick numbers, SI prefixes (1.2k, 3.4M), percentages, dates and money.
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.palette
A categorical palette of n colour-blind-safe colours for chart series: Okabe-Ito or Paul Tol's bright scheme.
charts.ticks
Axis ticks: a round step (1, 2 or 5 x 10^k), the ticks on it, and calendar ticks from days to years.
collections.diff
Compare two lists of records by key: which were added, which removed, and which changed and in what fields.
construction.payment-notice-dates
Construction Act default dates: payment due, payment notice, final date for payment and pay-less notice.
construction.vat-reverse-charge
Whether the UK VAT domestic reverse charge applies to a construction supply, and the invoice wording.
dates.add-months
Add calendar months to an ISO date, clamping to the month end: 31 Jan + 1 month is 28 or 29 Feb.
education.academic-year
The academic year and term a date falls in: 1 September to 31 August by default, terms from the caller.
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.solar-generation
Estimated annual solar PV generation by the MCS method: kWp x Kk x shade factor, per array and in total.
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.tax.vat-rate Unreviewed
Look up the VAT rate in force for a jurisdiction, category and date.
fleet.cost-per-mile
Whole-life cost per mile of a vehicle, in tenths of a penny, from depreciation, fuel, maintenance, insurance and tax.
fleet.ev-charging-cost
Cost of an electric vehicle charge from the energy added, charger efficiency and power, and time-of-use tariff windows.
hospitality.gross-profit-menu
Menu gross profit (GP%) on the VAT-exclusive price, and the menu price that reaches a target GP.
insurance.excess-apply Unreviewed
Claim payout after the compulsory and voluntary excess, capped at the policy limit.
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.
invest.cagr Unreviewed
Compound annual growth rate between two values over a whole or fractional number of years, in basis points.
invest.time-weighted-return Unreviewed
Time-weighted return from valuations taken at each external cash flow, geometrically linked exactly.
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.
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.hs-code-validate
Check the format of a commodity code: 6-digit HS, 8-digit CN or 10-digit TARIC/UK code, with chapter and heading checks.
logistics.route-distance
Total great-circle distance of an ordered list of stops, leg by leg, optionally back to the start, to the millimetre.
math.basis-points
Convert a rate between percent, basis points and a plain ratio exactly, as decimal text or integer basis points.
math.big-integer
Exact integer arithmetic of any size, on decimal strings, for powers and products that overflow 64 bits.
math.pow
base to the power exponent from + - * / only, exact by squaring for whole exponents, identical in every language.
math.rational
Exact fraction arithmetic, always reduced, for rates and ratios that must not drift.
math.sin-cos
Sine and cosine of an angle in radians from + - * / only, so every language returns the same doubles.
money.currency-digits
How many decimal places a currency's minor unit has, from the ISO 4217 list.
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.
property.completion-statement Unreviewed
A buyer's completion statement: price less deposit, ground rent and service charge apportioned to completion, plus fees.
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.checkbox-group React ^19 · TypeScript only
A question answered by ticking any of several checkboxes, with item hints and an exclusive "None" (GOV.UK checkboxes).
react.form.password-field React ^19 · TypeScript only
A password input with a Show/Hide button and an optional live checklist of a password policy (GOV.UK password input).
retail.basket-total
Total a basket: line prices, promotions, a basket discount, VAT per line and delivery, into one checked total.
retail.coupon-validate
Check a coupon against a basket: dates, usage limits, eligible products and minimum spend, with reason codes.
retail.gift-card-balance
Apply a payment from a gift card, redeeming part of the balance or all of it, and say what is still due.
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.shipping-rate
Delivery charge from a dated rate table by service, zone, chargeable weight and size, with a free-over threshold.
retail.volumetric-weight
Chargeable parcel weight: the greater of actual and volumetric (dimensional) weight, rounded up to a billing step.
text.format-decimal
Format a float as plain decimal text with fixed or trimmed places and optional grouping, identically in every language.
time.iso-to-unix
An RFC 3339 timestamp with a Z or offset, such as 2026-09-26T13:00:00+01:00, to Unix time in whole seconds.
todo.due-label
The short English label shown next to a todo: "2 days overdue", "Due today", "Due tomorrow", "Due Fri 2 Oct".
units.convert
Convert length, mass, area, volume, temperature and energy between units, exactly, as decimal text.
validation.nhs-number
Check an NHS number's modulus 11 check digit and normalise it to ten digits.
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-vat-number
Check a UK VAT registration number against HMRC's mod-97 checksum, including the post-2010 9755 variant.
agri.feed-ration
Ration costing and dry matter intake from each feed's fresh weight, DM % and price per tonne, in exact money.
auth.normalise-email
Trim an email address and lower-case its domain for storage and lookup, or null if it is not a plausible address.
banking.cheque-amount-words
The words and figures to write on a cheque: "One hundred and twenty pounds and fifty pence only", "£120.50".
banking.overdraft-interest
Overdraft interest for a statement period from daily balances, with an interest-free buffer.
charity.donation-matching
Employer match on a donation: a ratio in basis points, limited by a per-donor cap and a programme budget.
charity.gift-aid
Gift Aid a UK charity can claim on a donation: basic rate tax grossed up, 25p per £1 at 20%.
charity.gift-aid-eligibility
Whether a UK donation qualifies for Gift Aid: declaration, enough tax paid, and the donor benefit limits.
charity.payroll-giving
UK Payroll Giving for one pay period: the donation comes off pay before PAYE, and the tax it saves the employee.
charts.axis
Axis geometry as data: tick positions, tick marks, label anchors and gridlines for number, time and category axes.
charts.contrast
WCAG 2.x contrast ratio between two colours, and which text colour reads best on a background.
charts.histogram-bins
Bin values into histogram bins on round edges, by Sturges' rule, Freedman-Diaconis, or a fixed width.
charts.line-chart
Complete line chart geometry as data: plot area, number or date axes, gridlines, series paths, colours, legend.
charts.shape
SVG path strings for lines, areas, steps, monotone curves, bars, arcs and pie slices, identical in every language.
collections.dedupe-by-key
Remove records that share a key value, keeping the first or the last of each, in input order.
construction.cis-deduction
Construction Industry Scheme deduction (0, 20 or 30%) on the labour part of a subcontractor payment.
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.roof-pitch
Roof pitch in degrees, rafter length and roof slope area from span, rise and length.
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.
dates.day-of-week
The ISO 8601 day of the week for a date: 1 is Monday through 7 is Sunday.
dates.days-between
Calendar days from one ISO date to another, signed: negative when the second date is earlier.
education.attendance-rate
Pupil attendance and absence rates in basis points, with the DfE persistent and severe absence flags.
education.student-loan-repayment
A graduate's student or postgraduate loan repayment for a tax year, as Self Assessment works it out.
energy.carbon-emissions
kgCO2e from kWh or litres of a fuel, using the UK government GHG conversion factors for the year.
energy.water-bill
Metered water and sewerage bill from two reads: volumetric charges, return to sewer, standing and surface water charges.
finance.compound-interest
Compound interest accrued period by period in minor units, the way a statement is built.
finance.ledger.trial-balance
Trial balance from journal lines: debit or credit balance per account, and proof that debits equal credits.
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.
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.
health.appointment-slots Unreviewed
Bookable appointment slots from clinic sessions, a slot length, breaks and existing bookings.
health.bmi Unreviewed
Adult body mass index (kg/m², 1 decimal place) and its NICE/WHO weight category.
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.
hospitality.service-charge
A discretionary service charge on a bill's eligible lines, as a basis-point rate with explicit rounding.
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.
inventory.expiry-fefo
First-expiry-first-out pick list for a quantity across batches, skipping expired and short-dated stock.
inventory.reorder-point
Reorder point: demand over the supplier lead time, rounded up to whole units, plus safety stock.
inventory.safety-stock
Safety stock in whole units, by service level and demand variability (z-score) or by max-minus-average.
inventory.stock-turnover
Stock turnover ratio, days inventory outstanding and days of cover for a period, computed exactly.
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.
legal.limitation-date Unreviewed
The last day to bring a claim under the Limitation Act 1980, by claim type, from the date it accrued.
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.
logistics.demurrage
Demurrage or detention charge for a container: free days, then a tiered daily rate from the carrier's tariff.
manufacturing.batch-size
Economic batch quantity: the EOQ for a batch made at a finite production rate, in whole units.
manufacturing.bom-cost
Rolled-up standard cost of one unit of a product from its BOM, bought-in costs, and labour and overhead rates.
manufacturing.bom-explode
Explode a multi-level bill of materials into exact total quantities per component, with scrap and cycle checks.
money.sum
Total a list of monetary amounts, with an explicit currency for the empty case.
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.burn-rate-alert
Multiwindow, multi-burn-rate SLO alerting: which rules fire, from event counts per window (Google SRE workbook).