The Sales Tax / VAT Calculator answers one question well: how much tax is inside (or on top of) this amount? Whether you are pricing a product, checking a receipt, preparing a quotation, reconciling an invoice, or splitting a bill, you need the net amount, the tax portion and the tax-inclusive total to agree.
What it does
- Add Tax — enter a pre-tax amount and a rate; get the tax amount and the final total.
- Remove Tax — enter a tax-inclusive amount and a rate; get the original amount and the tax portion.
- Rate presets for 0%, 5%, 7.5% (Nigeria’s standard VAT rate), 10%, 15%, 20% and 25%, plus any custom rate you need.
- 22 currencies, with the Nigerian Naira (₦) as the default, formatted the way you expect to read them.
- Live results as you type, one-tap copy, and a full reset.
How it is built
The entire site is plain HTML, CSS and vanilla JavaScript — no frameworks, no build step, no backend, no database and no user accounts. Every calculation is performed by your browser on your device. The page loads once and then works even if you lose your internet connection.
Privacy by design: your calculations happen entirely in your browser. No financial data is uploaded to or stored on our servers, because there are no servers involved in the maths.
The formulas we use
- Add tax:
tax = net × rate ÷ 100andtotal = net + tax - Remove tax:
net = total ÷ (1 + rate ÷ 100)andtax = total − net
Values are rounded half-away-from-zero to the minor unit of the selected currency (two decimal places for most currencies, none for zero-decimal currencies such as the Japanese Yen and the CFA Franc).
Who it is for
Small business owners and shopkeepers, freelancers and consultants issuing invoices, accountants and bookkeepers doing quick sanity checks, students learning percentage arithmetic, and anyone comparing prices across countries with different VAT rates.
Feedback
Spotted a bug, or want a currency or preset rate added? Tell us on the contact page. And before you rely on a figure for a tax filing, please read the disclaimer.