VAT threshold planning calculator
The VAT registration threshold is based on a rolling 12-month total, not your tax year, which catches people out. Enter your numbers to estimate when you might approach the £90,000 line, so you can plan ahead instead of being surprised.
How the threshold actually works
You must register for VAT if your taxable turnover over any rolling 12-month period goes over £90,000, or if you expect it to go over £90,000 in the next 30 days alone. The rolling test trips far more businesses than people expect, because it is not measured against your accounting year. You can apply to deregister if turnover falls below £88,000.
If you cross the line, you generally must register within 30 days of the end of the month you went over, with registration effective from the first day of the second month after.
How to use the result
If you are within a few months of the threshold, plan early: decide whether to absorb VAT or raise prices, get your bookkeeping VAT-ready, and look at whether the Flat Rate or cash accounting schemes help. The worst position is crossing it by accident and finding you owe VAT you never charged.
VAT thresholds verified June 2026 from GOV.UK: register at £90,000, deregister at £88,000 (both unchanged since 1 April 2024). The time-to-threshold figure is a planning estimate based on a simple growth projection, not a forecast, and the rolling-12-month test depends on your actual month-by-month sales. Thresholds can change at fiscal events. This is not tax advice - speak to an accountant before registering.
Frequently asked questions
- What should I put in the 'taxable turnover, last 12 months' box?
- Enter your total VAT-taxable sales over the most recent rolling 12 months, not your accounting year. This is the figure the £90,000 registration test is measured against. Leave out anything that is exempt or outside the scope of VAT. Getting this right matters, because the tool calculates your headroom to £90,000 directly from it.
- Why does 'time to threshold' use my growth rate and monthly run-rate rather than just my last 12 months?
- The tool drops one old month at a time and adds a new month at your current monthly turnover, grown by your expected monthly growth percentage. It rolls this forward up to five years and flags the first month the rolling total passes £90,000. So your average monthly figure and growth rate drive the projection, while last year's total just sets the starting point.
- What does 'headroom to £90,000' actually tell me?
- It is simply £90,000 minus your rolling 12-month turnover, showing how much taxable sales you can still add over a rolling year before you hit the registration line. It does not change with your growth rate. Treat it as your current buffer: small headroom means you should plan pricing and registration now, not later.
- The result says I'm not projected to reach £90,000 within five years. Can I stop worrying?
- Not entirely. That message only reflects your current run-rate and steady growth assumption. The real test is your actual month-by-month sales, and a single busy quarter can push the rolling total over. You must also register if you expect to go over £90,000 in the next 30 days alone. Re-check the tool if growth accelerates.
- It says my turnover is already over £90,000. What should I do?
- The tool flags that you likely need to register now, but it cannot tell you exact dates. Generally you must register within 30 days of the end of the month you went over, with registration effective from the first day of the second month after. This is a planning estimate, not tax advice, so confirm the precise deadlines with an accountant.