Calculators for everything
82 free calculators with the formulas explained. No sign-up, no clutter.
Browse by category
- Math8 calculatorsPercentages, ratios, algebra and everyday arithmetic.
- Statistics3 calculatorsAverages, spread, z-scores and probability.
- Finance8 calculatorsLoans, interest, savings and investment growth.
- Health5 calculatorsBody measurements, fitness and wellbeing.
- Everyday life6 calculatorsTips, discounts, dates and daily decisions.
- Construction40 calculatorsConcrete, paint, tiles and materials for DIY and building projects.
- Physics3 calculatorsSpeed, density, electricity and other physics formulas.
- Chemistry3 calculatorsMolarity, dilutions, gas laws and lab calculations.
- Conversion6 calculatorsConvert length, temperature and other units.
Most popular
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Everyday life
Age Calculator
Find your exact age in years, months and days, plus the countdown to your next birthday.
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Construction
Air Conditioner BTU Calculator
Find the right air conditioner size in BTU for a room, using ENERGY STAR sizing guidance.
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Statistics
Average Calculator
Find the mean, median, mode and range of a list of numbers.
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Health
BMI Calculator
Calculate your body mass index in metric or imperial units and see your healthy weight range.
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Construction
Brick Calculator
Estimate how many bricks you need for a wall based on brick size, mortar joints and openings.
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Health
Calorie Calculator
Estimate the daily calories you need to maintain, lose or gain weight.
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Finance
Compound Interest Calculator
See how savings grow with compound interest and regular deposits, year by year.
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Construction
Concrete Calculator
Work out how much concrete a slab needs in cubic yards, cubic metres and bags.
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Construction
Cubic Yard Calculator
Convert length, width and depth into cubic yards, cubic feet and cubic metres.
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Everyday life
Days Between Dates Calculator
Count the days, weeks and weekdays between two dates.
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Construction
Decking Calculator
Calculate how many deck boards, joists and screws you need for a rectangular deck.
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Everyday life
Discount Calculator
See the sale price and how much you save, with optional sales tax.