Free online tools
Calculators that just work.
A growing library of fast, accurate calculators and converters for finance, health, construction, cooking, education and everyday math — no sign-up, no clutter.
- 95 free calculators
- No sign-up
- Works on any device
Popular calculators
Compound Interest Calculator
See how savings grow with interest and regular contributions.
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Loan & Mortgage Calculator
Work out monthly repayments, total interest and a payoff schedule.
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BMI Calculator
Calculate Body Mass Index and see your healthy weight range.
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Percentage Calculator
Find a percentage of a number, a ratio, or a percentage change.
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Finance
Loans, savings, interest and everyday money math.
Bill Split Calculator
Split a bill with tip evenly between any number of people.
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Break-Even Calculator
Find the units and revenue needed to break even.
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Compound Interest Calculator
See how savings grow with interest and regular contributions.
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Discount Calculator
Find the sale price and how much you save in a sale.
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Health & Fitness
Body metrics, nutrition and wellbeing.
Blood Pressure Category
See which category a blood-pressure reading falls into.
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BMI Calculator
Calculate Body Mass Index and see your healthy weight range.
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Body Surface Area Calculator
Estimate body surface area from height and weight (Mosteller & Du Bois).
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Calories Burned Calculator
Estimate the energy used during exercise from activity, weight and time.
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Construction & DIY
Materials, areas, volumes and project planning.
Asphalt Calculator
Estimate the tonnage of asphalt for a driveway or path.
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Board Feet Calculator
Calculate lumber board feet and cost from board dimensions.
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Brick Calculator
Estimate how many bricks a wall needs, with a wastage allowance.
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BTU Calculator (Heating & Cooling)
Estimate the BTU capacity a room needs for cooling or heating.
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Cooking
Conversions and scaling for the kitchen.
Baking Pan Size Converter
Scale a recipe between pan sizes and shapes by comparing areas.
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Brine Calculator
Work out the salt for a wet brine at a chosen concentration.
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Butter Converter
Convert butter between sticks, grams, ounces, cups and tablespoons.
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Air Fryer Conversion Calculator
Convert conventional oven temperature and time to air-fryer settings.
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Education
Grades, study and learning helpers.
Density Calculator
Solve density, mass or volume using density = mass ÷ volume.
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Final Grade Calculator
Find the exam score you need to hit your target grade.
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Fraction Calculator
Add, subtract, multiply or divide fractions, simplified automatically.
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GPA Calculator
Work out your grade point average from course grades and credits.
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Math & Conversions
Everyday arithmetic, percentages and units.
Age Calculator
Work out an exact age in years, months and days from any birth date.
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Aspect Ratio Calculator
Resize dimensions while keeping the aspect ratio, and simplify it.
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Circle Calculator
Find a circle’s radius, diameter, circumference and area from any one.
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Area Calculator
Find the area and perimeter of rectangles, circles and triangles.
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Unit Converters
Convert length, weight, temperature, and other measurement units.