What is UK VAT Calculator?
The UK VAT Calculator is a free, client-side tool built for the 2026/27 tax year that handles the three core VAT tasks most UK businesses face: adding or removing VAT at 20%, 5%, or 0%, tracking your £90,000 registration threshold across a rolling 12-month period, and comparing the flat rate scheme against standard VAT accounting. Everything runs locally in your browser — no data is sent anywhere, and there's no sign-up or account required. It's updated to reflect current HMRC rates and the £90,000 threshold as of April 2026.
Who it's for
- Freelancers and sole traders — who need quick, accurate VAT calculations without logging into accounting software every time.
- Small business owners near the threshold — who want a month-by-month view of their rolling 12-month turnover to avoid surprise VAT registration.
- Flat rate scheme candidates — who are weighing whether the simplified flat rate percentage beats standard input/output VAT accounting for their sector.
Key features
Add or remove VAT at three rates
The core calculator handles net-to-gross and gross-to-net conversions at 20%, 5%, and 0%. Zero-rated supplies are clearly flagged as still counting toward your registration threshold, which is a distinction many tools gloss over.
Rolling 12-month threshold tracker
Enter your monthly turnover for the last 12 months and the tool compares your rolling total against the £90,000 HMRC threshold. A month-by-month table shows your status as you approach the limit, so you can plan registration timing with confidence.
Flat rate scheme comparison
Input your annual gross turnover, VAT-able purchases, and business sector to see a side-by-side comparison of net VAT payable under the standard scheme versus the flat rate scheme. Sector-specific percentages are built in, from advertising at 14.5% down to retailing at 7.5%.
VAT rules reference
The tool includes a clear breakdown of UK VAT rates for 2026/27 — standard, reduced, zero, and exempt — plus practical guidance on how to add VAT manually and what counts toward your threshold.
What stands out
All free, no sign-up. Client-side, no data sent anywhere.
That's the whole pitch, and it holds up. Most VAT tools either push a paid tier, require an account, or send your financial data to a server. This one does none of those things. The threshold tracker and flat rate comparison are genuinely useful planning tools, not just a basic calculator dressed up with ads. The sector-specific flat rate percentages and the limited cost trader rule (16.5% for businesses with low VAT-able purchases) make it a practical decision-making aid, not just a number cruncher.
Worth checking out if…
You're a UK freelancer, contractor, or small business owner who wants a fast, private VAT calculator that also helps you plan around the registration threshold and decide whether the flat rate scheme is worth it. It's especially useful if you're approaching £90,000 in turnover and need a clear month-by-month picture, or if you're in a sector with a favourable flat rate percentage and want to see the actual pound difference before switching.
