How we check our figures

The rates and thresholds behind SavingTax come from GOV.UK. Here is how we check them, who does it and what the checks cannot tell you.

Reviewed by Adewale Adetomi · Last checked 6 November 2026

Where the figures come from

The app's tax rates and thresholds are taken from GOV.UK pages: Income Tax rates and Personal Allowances, National Insurance rates, Capital Gains Tax rates, dividend and savings allowances, Child Benefit, Marriage Allowance and pension allowances. They are held for each tax year the app supports, from 2021-22 to 2026-27.

How we check them

A person compares each value with GOV.UK. On 6 November 2026 we compared the app's figures with the GOV.UK page for each one, for the recent tax years, and wrote down which values were confirmed, which were wrong and which could not be checked that day.
Corrections are made and recorded. Where a value differed from GOV.UK, we are correcting it. Corrections reach the app with its updates, so the version you have installed may not yet include the latest ones.
Automated tests catch some mistakes. The app keeps a snapshot of every threshold it uses, and a test fails when a figure changes without the snapshot being updated, so a change is always reviewed. Other tests check relationships that must hold, for example that the basic rate limit is the Personal Allowance plus £37,700.
Our backend's copy is compared with the app's. The same figures are used on our server, so we compare the two copies and list any difference.

What the checks cannot do

Tests and matching copies do not prove a figure is right. Both copies were built together, so they can share a mistake, and in our November check some values that matched each other still differed from GOV.UK. Only comparing a figure with GOV.UK catches that, so a person repeats the comparison each April and whenever a new tax year is added.

We did not re-check everything in November. Older years (2021-22 and 2022-23) and some figures that GOV.UK pages do not list for past years were not confirmed that day. Where a tax year had a change part-way through, such as some National Insurance and Capital Gains Tax rates, the app uses a single set of figures for the year and says so.

What this means for you

SavingTax gives estimates based on the figures you enter and the published rates. It is general information, not financial, tax or legal advice, and it is not Making Tax Digital software and does not file anything with HMRC. If you think a figure is wrong, please tell us at support@savingtax.uk and include the tax year and where you saw it. We'll check it against GOV.UK.