# property.council-tax-band
Every council tax band is charged as a fixed proportion of Band D, set in
statute. The authority publishes its Band D figure each year; this turns it
into the charge for any band:
charge = Band D × band proportion ÷ Band D proportion
`councilTaxBand(money(200000, "GBP"), "A", "england", "2026-04-01")` is
£1,333.33: six ninths of £2,000.
## The ratios, as dated data
`data/band-ratios.json` holds each nation's proportions with the dates they
apply from:
| nation | from | A | B | C | D | E | F | G | H | I |
|---|---|---|---|---|---|---|---|---|---|---|
| England | 1 April 1993 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 18 | |
| Wales | 1 April 1993 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 18 | |
| Wales | 1 April 2005 | 6 | 7 | 8 | 9 | 11 | 13 | 15 | 18 | 21 |
| Scotland | 1 April 1993 | 240 | 280 | 320 | 360 | 440 | 520 | 600 | 720 | |
| Scotland | 1 April 2017 | 240 | 280 | 320 | 360 | 473 | 585 | 705 | 882 | |
England and Wales are ninths of Band D; Scotland is written in 360ths. Band I
exists only in Wales, from the 2005 revaluation; asking for it elsewhere, or
for a band before it existed, is an error. Scotland's 2017 change raised
bands E to H only.
Pass any date inside the financial year (1 April to 31 March) being charged.
## Rounding
The exact fraction is rounded half-up to the penny, once. Authorities differ
in how they round instalments; that is not this function's job.
## What it does not do
Discounts (the 25% single person discount), exemptions, disabled band
reduction, premiums on empty and second homes, and splitting the charge
into instalments. Northern Ireland has domestic rates, not council tax.
## Sources
- Local Government Finance Act 1992, section 5(1) (England: 6:7:8:9:11:13:15:18)
and 5(1A) (Wales, for financial years beginning on or after 1 April 2005:
6:7:8:9:11:13:15:18:21): https://www.legislation.gov.uk/ukpga/1992/14/section/5
- Local Government Finance Act 1992, section 74(1) (Scotland:
240:280:320:360:473:585:705:882): https://www.legislation.gov.uk/ukpga/1992/14/section/74
- The Council Tax (Substitution of Proportion) (Scotland) Order 2016 (SSI
2016/368), for financial years beginning on or after 1 April 2017, the
first change to the Scottish proportion since 1992:
https://www.legislation.gov.uk/ssi/2016/368/made . The pre-2017 Scottish
row (240:280:320:360:440:520:600:720) is the original 1992 proportion
expressed in 360ths, identical to England's 6:7:8:9:11:13:15:18.
1.0.1 fixes Python accepting a trailing newline or non-ASCII digits in onDate; adds tests.
## Before you rely on this
**Not professional advice.** This capability calculates property figures from published rules. It is a software component for developers, not legal or financial advice. Rules change and every rate here has an effective date. Check that the dates cover your case. Verify results against the official sources listed above, and have a conveyancer or tax adviser review how you use it, before anyone relies on the output. Provided "as is" under its licence, without warranty.
**Unreviewed.** This capability's implementations agree in every language and pass its published test vectors, which were worked out from the official sources cited. But no qualified conveyancer or tax adviser has yet checked those vectors, or confirmed that the capability covers the cases it claims. Treat it as a draft. Do not use it for real people, money or decisions without your own expert review. Once a qualified reviewer signs off, this notice is replaced with their name, qualification and the date. Each new version needs fresh sign-off.
## Notices
Contains public sector information licensed under the Open Government
Licence v3.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).
Legislation: Crown copyright and database right.
1.0.2 marks it unreviewed and adds its attribution notices (NOTICE). The code and the tests are unchanged.