About DailyCalc
DailyCalc is a free collection of calculators and unit converters for everyday questions: how old you are in days, what a loan will cost each month, how many grams are in a cup of flour. The site is run by Hafiz Muhammad.
Our goal is simple: give a correct answer quickly, show how it was worked out, and let you check the source. There are no sign-ups, and the calculations run in your own browser.
How we build and verify our calculators
Every tool goes through the same process before it is published:
- Research. We study what people actually ask about the topic and which conventions differ between countries, such as US and UK gallons or the ways lenders round loan payments.
- Primary sources. Formulas, constants and conversion factors are taken from the organisation that defines them: NIST and the International Bureau of Weights and Measures for units, the World Health Organization and national health agencies for health measures, and the original published papers for named formulas. Each tool page lists its sources.
- Automated tests. Every formula has automated tests built from reference values taken from those sources, plus edge cases such as leap years, zero and very large numbers. A tool cannot be published if a test fails.
- Clear conventions. Where experts or countries disagree, the tool shows the options side by side with labels instead of silently picking one.
- Review and updates. Each page shows the date its content or formula last changed. We revisit tools when the underlying guidance changes.
How the content is written
Research notes and explanations are drafted with the help of AI tools and then checked against the cited primary sources. Numbers in worked examples are produced by the same tested code that powers the calculator, so the examples and the tool always agree.
Health and money tools
Health and finance calculators give estimates for general information. They are not medical, financial or tax advice. Please read our disclaimer, and speak to a qualified professional before making decisions based on a result.
Privacy by design
Your inputs are processed on your device. A few tools, such as the currency converter, fetch public reference data; our privacy policy lists exactly which services are contacted and why.
Found a mistake?
Accuracy matters more to us than anything else. If a result looks wrong, please contact us with the page and the numbers you entered, and we will check it against the sources and fix it.