Why I built one calculator instead of bookmarking five different sites
For a while, I had five different tabs bookmarked. One for UK VAT, one for Australian GST, one for a Canadian HST calculator that only covered Ontario, and two more I’d half-forgotten the names of. Every time I billed a client outside my own country, I’d dig through my bookmarks, pick the least broken-looking site, and hope the numbers were right.
They usually were. Not always.
I do freelance design work, and my clients aren’t all in one place — some in London, a couple in Sydney, one in Toronto, a handful scattered across the US. Every one of those invoices needs a different tax treatment, and every one of those calculators wanted something different from me: an email address, a forced sign-up, three pages of ads before the actual number showed up.
So I built this instead. Four calculators, one page, no sign-up wall in the way.
What’s actually here
Right now this covers the four places I personally deal with most: UK VAT, Australian GST, Canadian GST/HST by province, and US sales tax by state. Each one does the same basic job — add tax to a number, or work backward from a total to find out what the pre-tax amount was — but the actual rates and rules are different enough in each country that a single “one-size-fits-all” calculator never really works properly. That’s why these are separate tools rather than one generic box that tries to do everything.
Who this is actually for
If you’re a freelancer, a small business owner, or you just do the books for a small team, this is built for the exact situation I kept running into — needing a quick, accurate number without digging through five bookmarks or waiting for an accountant to reply to an email. It’s not a replacement for actual tax advice on anything that matters legally. It’s the tool I reach for before that conversation, not instead of it.
A quick honest note
These calculators use standard published rates. Tax rules have exceptions, thresholds, and regional quirks that a simple calculator can’t fully capture — a reduced VAT rate on children’s items, a GST exemption on certain provinces, state-specific sales tax holidays. If you’re filing something official, use this to get a fast estimate, then double-check the specific number against HMRC, the ATO, the CRA, or your state’s Department of Revenue, depending on which one applies to your situation.
Pick a calculator to get started.
Frequently Asked Questions
Is this site actually free to use? Yes. Every calculator on this site is free, with no sign-up, no email requirement, and no premium tier. That was the entire point of building it — most of the tools I used to rely on hid basic math behind some kind of paywall or lead-capture form.
Do you store the numbers I enter? No. Every calculation runs locally in your browser using JavaScript. Nothing you type gets sent to a server, logged, or saved anywhere. Close the tab and it’s gone.
Which countries do you currently cover? Right now: UK VAT, Australia GST, Canada GST/HST by province, and US sales tax by state. I’m a freelancer dealing with clients across all four regularly, which is why these were the first ones built.
Are the tax rates always up to date? I keep them current with standard published rates, but tax rules change, and I’m one person maintaining this, not a team monitoring every jurisdiction daily. If you spot something outdated, the contact page is the fastest way to flag it.
Can I use these calculators for official tax filings? Use them to get a fast, reliable estimate — but for anything you’re actually filing, cross-check the number against HMRC, the ATO, the CRA, your state’s Department of Revenue, or a qualified accountant, depending on which applies to you. I’m not a tax professional, and this isn’t a substitute for one.
Will you add more countries or calculators? Likely, yes — this started as four tools I personally needed, and it’ll probably grow the same way, based on what people actually ask for.