About Mathmatives

Mathmatives is a collection of free online calculators for everyday number questions: comparing pay, planning savings, renting versus buying, estimating calories, budgeting for a car, and pricing freelance work. Everything runs in your browser. There are no accounts, no paywalls and no data collection. Calculations happen on your device and are never sent anywhere.

Our methodology

Every calculator follows the same standard. The formula is shown on the page, exactly as the code computes it. A worked example shows the calculation by hand so you can check the result. Assumptions are stated, not hidden. Where a question needs a professional, such as medical decisions, tax specifics or investment advice, the page says so.

Formulas come from standard, well-documented sources: amortization math for loan and mortgage tools, the Mifflin-St Jeor equation for energy expenditure, Naegele's rule for pregnancy dating, and standard cost-volume-profit analysis for business tools. Where experts disagree, pages present the mainstream position and note the uncertainty.

What these calculators are not

They are educational tools, not advice. Results are estimates based on the inputs and assumptions shown, and they cannot account for your full situation. For decisions with significant financial, legal or health consequences, use these tools to get informed, then confirm with a qualified professional.

Corrections

Accuracy is the whole point of a calculator site. If you think a formula, example or explanation is wrong, tell us and we will review it promptly. Contact: corrections@mathmatives.com (replace with your real address before launch).