About Calc Garden
Calc Garden is a growing library of free online calculators for personal finance, fitness, home projects, taxes and small business. The goal is simple: give you a fast, focused tool that lands with sensible defaults already filled in, so you see a useful answer the moment the page loads.
Every calculator on the site is built to do one job well. There is no sign-up, no paywall and no clutter. You change a few inputs, the numbers update instantly, and you move on with your day.
What is on the site
There are currently 79 calculators and 67 written guides, split across six sections. The calculators do the arithmetic. The guides explain the reasoning behind a number, which is usually what you actually need when the result surprises you.
Who it is for
Calc Garden is for anyone who needs a quick, reliable estimate. That might be a homebuyer checking a mortgage payment, someone planning their retirement number, a freelancer working out take-home pay, or a group splitting a restaurant bill. If a calculation is common enough to search for, we want a clean tool for it here.
The assumption behind every page is that you arrived from a search with one specific question and want the answer without an account, an email capture or a walkthrough. Defaults are filled in so the page is useful before you touch anything, and the inputs are the smallest set that still produces an honest result.
How a calculator here is built
Each calculator is a single page with the form on one side and the result on the other. There is no submit button. The result recomputes as you type, so you can drag an input around and watch which numbers actually move, which is often more informative than any single answer.
Underneath the tool, most pages carry the method written out: what the formula is, a worked example with real inputs and the output they produce, the limitations of the estimate, and the mistakes people commonly make with that kind of calculation. That section exists because a number with no working shown is hard to trust and impossible to check.
Where a page shows a reference table as well as the interactive tool, the table and the calculator read their figures from the same place in the code rather than each holding a copy. It is a small detail, but it means the table you can read without running anything cannot quietly drift away from the numbers the tool produces.
How we try to keep the numbers right
Figures that come from published data carry the year they apply to, and name the source where the source is the point. Tax bands, rates and cost benchmarks change, so a page that quietly implies its numbers are timeless is worse than useless. Worked examples are checked against what the tool itself returns for those inputs, not written from memory alongside it.
Where a calculation is simplified, the page says so. The take-home pay estimate, for example, applies the two largest statutory deductions using simplified bands, which makes it a good ballpark and a poor substitute for a payslip. Saying that plainly on the page is more useful than a false claim of precision.
If you find a wrong number, tell us and we will fix it. Corrections get priority over new pages, and a page that changes materially has its update date changed with it.
Update dates mean something here
Most sites stamp every page as updated on every deploy, which turns the date into noise. Calc Garden does the opposite. A page carries the date its content genuinely last changed, and pages that have not changed keep their older date instead of borrowing today's. A check runs against the project's own version history before publishing, and it fails if any page claims to be fresher than its last real content change. If a page here says it was updated in a given month, something on it actually changed that month.
What Calc Garden is not
The results are estimates for general information. They are not financial, tax, legal or medical advice, and they are not a substitute for a mortgage adviser, an accountant or a doctor. A calculator can tell you what a formula returns for the numbers you entered. It cannot know your circumstances.
A good number of the tools default to UK conventions, currency and tax rules, because that is where most of our readers are. Many work anywhere once you change the inputs, but check the assumptions spelled out on the page before relying on one somewhere else. Where a tool uses rates that move, such as exchange rates, those are entered by hand and dated on the page rather than pulled live, so treat them as a reference point rather than a quote.
Your data
All calculations run entirely client-side in your browser. Nothing you type into a calculator is sent to a server or stored by us. When you close the tab, the numbers are gone.
The site does record anonymous usage events of its own, such as which calculator was opened and that a calculation was run, along with standard web analytics. Those events record the page, never the values you entered, and they are not tied to any account or identity. The privacy policy sets out exactly what is collected and which third-party tools are involved.
Who runs it
Calc Garden is built and maintained by a small, independent team that makes free, no-signup web tools. It is part of a small network of free tools alongside Tools Nimbus for browser dev tools, Cent Signals for Polymarket data and explainers, QuizVault for quizzes and personality tests, and PlayBrain for browser games.
Calc Garden is free to use and there are no ads running on it today. It is built to be supported by advertising, and some pages have a slot for a relevant affiliate link, so that will change. Neither will ever change what a calculator returns. The maths does not know what is on the page next to it, no tool here is weighted toward a product or a lender, and anything we would earn a commission on is labelled where it appears.
Suggestions and corrections
Have a calculator you would like to see added, or found something wrong? Requests genuinely do decide what gets built next, so get in touch. You can also browse everything from the homepage or read the guides.