Calclumo is a collection of 35 free calculators that answer everyday questions in seconds. Everything runs directly in your browser: values stay on your device, results appear after you calculate, and there are no accounts or paywalls. Each calculator explains its formula and shows worked examples, so you can check the math yourself.

Percentages and shopping

Use the percentage calculator for quick "X% of Y" questions, the percentage increase/decrease calculator for growth and change, the discount calculator for sale prices and stacked coupons, the VAT / sales tax calculator to add or remove tax, and the tip calculator to split any restaurant bill.

Loans, mortgages, and income

The loan payment calculator estimates monthly payments and total interest with the standard amortization formula, while the mortgage calculator adds property tax, insurance, PMI, and HOA for a realistic monthly housing cost. The salary calculator converts hourly and yearly pay with overtime, bonus, deductions, pay frequency, and a rough net estimate.

Health and fitness

Check your body mass index with the BMI calculator, estimate your resting burn with the BMR calculator (Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle), and turn it into a daily calorie target and macro split with the calorie calculator.

Dates, time, and unit conversion

The age calculator gives an exact age in years, months, and days; the date difference calculator counts calendar days, business days, weekends, and custom exclusions; and the time duration calculator tracks shift hours, breaks, rounding, overtime, and pay. For units, the unit converter covers length, weight, area, volume, and temperature in one place, with dedicated length, weight, and temperature converters, plus an area calculator and volume calculator for geometry.

Frequently asked questions

Are Calclumo calculators really free?

Yes. Every calculator on Calclumo is completely free, with no accounts, paywalls, or usage limits. Open a calculator and start typing — that is all.

Do you store the numbers I enter?

No. All calculations run directly in your browser using JavaScript. The values you type are never sent to our servers, stored, or shared.

How accurate are the results?

Each calculator uses a standard formula for its task — for example, amortization for loans, Mifflin-St Jeor for calorie estimates, and exact unit conversion factors. Financial and health results are estimates for guidance, not professional advice.

Do the calculators work on mobile?

Yes. Calclumo is designed for phones first, so every calculator works comfortably on any screen size — mobile, tablet, or desktop.

What types of calculators are available?

Calclumo covers six areas: percentages and everyday math, personal finance (loans, mortgages, salary), health and fitness (BMI, BMR, calories), dates and time, unit converters, and geometry (area and volume).

Do I need to install anything?

No. Calclumo runs entirely in your web browser. There is nothing to download or install, and results appear instantly as you type.