Two dates, two different questions. Rate changed is when the figure last moved — it comes from the Budget or Finance Act that set it. Last checked is when one of us last confirmed it against HMRC. A rate unchanged since 2023 may be perfectly correct; what the change date alone cannot tell you is whether anybody has looked. Check the whole of a tab, then run:

node check-tax-rates.js --verify national_insurance --by "your name"

Never overwrite a rate that has changed. Editing the value in place destroys the history, and every figure we have ever reported to a client was calculated on the rate in force at the time. Add a new row with the date it took effect; the old one closes automatically and stays readable. Editing in place is for correcting a mistake, not for recording a change.

Three names that will not match gov.uk.

• This PAYE tab is Income Tax. HMRC has no "PAYE rates" page — PAYE is how it is collected. Use Income Tax rates and Personal Allowances.
• Corporation Tax thresholds are limits at HMRC.
• Basic rate limit (£37,700) is a band width and is not printed anywhere on gov.uk — it is £50,270 − £12,570. And our higher rate threshold is where the basic band ends (£50,270) while HMRC states where the higher band starts (£50,271). Both are right. Do not "correct" either to match the other.

Worked examples — check any change against these before saving. If an answer moves and you did not expect it to, stop.

Where a rate is missing entirely. We hold no under-21, apprentice or veteran Secondary Thresholds, so employer NI is overstated for those employees; no Scottish income tax bands; and CIS late-filing penalties stop at two months where HMRC has four tiers. Those are gaps in the table rather than rates to update — tell me if any client needs one and I will add it.