calculate.at

Hey everyone — sharing calculate.at, a free calculator site I've been building solo for a while now.

The short version: it's a collection of 290+ calculators — mortgages, loans, tax, BMI, calories, percentages, unit conversions, construction material estimates, date math, and a few games mixed in. No account, no premium tier, nothing to pay for. You land directly on the calculator you searched for and get a result.

It started small — I built one calculator for a problem I actually had (figuring out a mortgage payment without re-deriving the amortization formula every time), and just kept adding more whenever I hit a new one I wanted. That's still basically the process. There's no roadmap doc, just "did I personally need this calculator this week."

A few decisions I'd call out if anyone's building something similar:

• Unit converters used to be one bidirectional tool per unit type. I split them into one page per direction (miles→km separate from km→miles) after noticing that's much closer to how people actually search for these. More pages, but each one is simpler and more targeted than the combined version was.

• No account system anywhere. Partly because I never needed one myself, partly because I think a calculator site should work the same on your first visit as your hundredth.

• Sharing a specific result is one click on most calculators — a permalink with your inputs baked in, not a screenshot.

What's next: more calculators (there's always a gap somewhere), and I'm slowly working on embeddable versions of the more popular ones so other sites can use them directly.

Happy to answer questions about the build, the stack, or the SEO/traffic side of running something like this. And if you land on it and a calculator is missing that you'd actually use, tell me — that's basically how the whole catalog got built.