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Two jobs, one tool. Add tax to a price to get the total to put on an invoice — or work backward, pulling the tax out of a tax-inclusive total to see how much of it is actually yours and how much you owe the tax authority. Sales tax, VAT, GST: same math, your rate.
Nothing you type leaves your browser. Tax rates and the rules for who must charge them vary by place and by what you sell — always confirm yours. This isn't tax advice.
Tax sits on top of a price as a flat percentage, which makes the arithmetic simple once you're clear on which number the percentage is measured against. There are only two situations, and this calculator does both:
Adding tax is the forward direction — you have a pre-tax price and need the total to put on the invoice. You multiply the price by the rate to get the tax, then add it back on:
Removing tax — the "reverse VAT" direction — is the one people get wrong. You have a tax-inclusive total (a client paid you a round number, or a price was quoted "inc. VAT") and you need to pull the tax back out. The trap is subtracting the rate from the total: that's too much, because the rate was applied to the smaller pre-tax figure, not the bigger inclusive one. The right move is to divide:
Both directions land on the same identity — pre-tax + tax = total — which is exactly the line the ledger above reconciles, to the cent, whichever way you're working.
Here's the quirk worth internalizing, because it's where reverse calculations go sideways. A 20% VAT on a £100 item adds £20, for a £120 total. But that £20 of tax is only 16.67% of the £120 — not 20% — because it's now being measured against the larger, tax-inclusive number. It's the same trap as markup versus margin: one amount of money, two different bases, two different percentages. So to back the tax out of an inclusive total, you can't just take 20% of it — you divide by 1.20. The calculator shows you "tax as a share of the total" precisely so this never bites you.
It depends entirely on where you are and what you sell. In much of the US, professional services (design, writing, consulting, development) are often exempt from sales tax, while physical goods and some digital products are taxable — and the rules differ state by state, sometimes county by county. Outside the US, VAT or GST commonly applies to services too, often once you cross a registration threshold. The safe move is to confirm your obligation with a local accountant or your tax authority; this tool handles the arithmetic once you know your rate, but it can't tell you whether you're required to charge.
Divide the tax-inclusive total by 1 plus the rate as a decimal — so for 8% tax, divide by 1.08. That gives the pre-tax amount; subtract it from the total to get the tax. Don't simply take 8% of the total: the tax was charged on the smaller pre-tax figure, so taking 8% of the larger inclusive number overstates it. Switch this tool to Remove tax and it does the division for you.
For a single transaction, the arithmetic is identical: a flat percentage on top of a price. The differences are structural, not mathematical — VAT and GST are usually shown tax-inclusive and collected at each stage of a supply chain (with businesses reclaiming the VAT they pay), whereas US sales tax is added at the till and collected only at the final sale. This calculator works for any of them; you just enter your rate and pick whether you're adding or removing the tax.
The combined rate that applies to your sale. In the US that can mean stacking a state rate with county and city rates into one figure — for example a 6% state plus 2.875% local is 8.875%. For VAT or GST it's typically a single national rate (e.g. 20% in the UK, 10% in Australia), though some countries have reduced rates for certain goods. The presets give a few common starting points, but confirm the exact rate for your location and category.
If you're required to collect sales tax, VAT, or GST, it's a pass-through: you add it on top, the client pays it, and you remit it to the authority — it was never your money. That's different from a processing fee or your own overhead, which come out of what you keep and belong in your rate. Keep the tax you collect separate from your income so you're not surprised when it's time to remit.
No. Every calculation runs entirely in your browser — nothing you type is sent to a server or stored. The link in your address bar updates so you can bookmark or share a scenario, but it only contains the numbers and direction you chose.
Keep going
Drop your pre-tax line items and tax rate in and download a clean, professional invoice.
The same one-number-two-bases idea, applied to pricing: why a 50% markup is only a 33% margin.
Work out what to charge so the processor's cut still leaves you the amount you wanted.