Running the business
VAT registration threshold headroom
- where
- headroom below the threshold (£)
- VAT registration threshold (£)
- taxable turnover in the last 12 months (£)
- turnover as a share of the threshold (%)
Explain this equation
Shows how close your turnover is to the VAT registration threshold. Use it at the end of each month.
T12 is your taxable turnover for the last 12 months, Th the threshold (£90,000 at November 2026). H is the headroom left and p is your turnover as a percentage of the threshold.
It is a simple subtraction and ratio because the rule is a straight comparison: if turnover in any rolling 12 months goes over the threshold, you must register.
Sense check: £82,000 of turnover leaves £8,000 of headroom and is 91% of the threshold, close enough to watch every month. A negative headroom means you must register within 30 days of the end of that month.
Watch out: turnover means total sales including materials you charge for, not profit, and the test is rolling, not by tax year.
Shows how close your rolling 12-month turnover is to the VAT registration threshold.
Enter your values to see the result.
Good to know
The registration threshold is £90,000 of taxable turnover in any rolling 12-month period, not the tax year (GOV.UK, unchanged since 1 April 2024 and current as at November 2026). You must also register straight away if you expect turnover in the next 30 days alone to go over the threshold. Turnover means total sales (including materials you charge for), not profit.
Common mistake
Checking only at the tax year end. The test is rolling: add up the last 12 months at the end of every month.
Limits
Simple comparison. Does not cover exempt supplies, the deregistration threshold or voluntary registration. Re-check the threshold on GOV.UK if it changes.
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the manufacturers’ system and product data, BS 8212, BS EN 13914 and Building Regulations. Coverage rates vary by product, background and thickness. Check prices, VAT and CIS rules with your own records and HMRC.