Calculator.net
FreeHundreds of specialised free calculators in one place — mortgage, BMI, percentage, compound interest, due-date, GPA and a full scientific calculator, each with formulas explained under the result.
Why we recommend Calculator.net
'Calculator' draws about 34 million searches a month, and calculator.net wins so much of that traffic because it treats calculation as a content problem: it hosts hundreds of purpose-built calculators — amortisation schedules, BMI with health ranges, inflation, ovulation, subnet masks — and under every result it shows the formula and worked explanation. That transparency is why teachers and finance forums link to it. Is it free? Completely, ad-supported, with no account for anything.
Best use cases
How to use it: go to calculator.net, pick a calculator from the categories or search box, fill the fields and hit Calculate — results, charts and step-by-step breakdowns render instantly on the page. Nothing to install, and every calculator has a stable URL you can bookmark or share. Best for mortgage what-ifs, percentage arithmetic you don't trust yourself with at midnight, and homework where you need the method, not just the answer.
Honest limitations
Does it work offline? No — pages are server-rendered, so a lost connection means no calculator; there is no PWA or offline cache. The 1990s-plain design and ads put some people off, precision on scientific edge cases trails a real TI or Wolfram Alpha, and for symbolic math (algebra steps, calculus) you'll want Desmos or Wolfram instead.
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