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Calculators that show their working.
Free online calculators for finance, health, math, science, engineering, and everyday life. Fast, accurate, no sign-up.
Browse by category
- Financial31Work out what a loan really costs, how fast savings compound, and what you can afford — using the same formulas banks use.
- Health & Fitness18Estimate body composition, energy needs, and training targets with the standard clinical and sports-science formulas.
- Math23Solve the everyday math that comes up in school, work, and DIY — with every step shown, not just the answer.
- Everyday17The small calculations that come up constantly — split a bill, count the days, convert the units.
- Science10The working behind physics and chemistry homework — solve a named law for any variable, and see which formula was used.
- Engineering1The geometry and mechanics behind a design — worked from first principles, with every formula written out beside the number it produced.
Most used
- Mortgage CalculatorCalculate your monthly mortgage payment including principal, interest, taxes, insurance, and PMI. Supports 10, 15, 20, and 30-year fixed loans.
- Loan CalculatorWork out the monthly payment on any personal, auto, or student loan, see the total interest, and check how much an extra payment saves.
- Retirement CalculatorProject your retirement savings from your current balance, monthly contributions, and expected return, then see the yearly income the 4% rule allows.
- 401(k) CalculatorProject your 401(k) balance at retirement, and see what contributing below your employer match cap costs you in free money by the time you stop working.
- Roth IRA CalculatorCompare a Roth IRA with a traditional IRA at the same gross cost, and find the retirement tax rate at which the two are worth exactly the same.
- BMI CalculatorCalculate your body mass index from height and weight in metric or imperial units, see your BMI category, and find your healthy weight range.
- TDEE CalculatorEstimate your total daily energy expenditure from height, weight, age, sex and activity level, plus the intake for losing or gaining weight.
Quicky
84 calculators as one-line rows — type across, the green cell answers
Financial
Mortgage CalculatorOpen →
| Home price | Down payment | Annual interest rate | Loan term | Property tax | Home insurance | Monthly principal & interest |
|---|---|---|---|---|---|---|
| $2,022.62 |
Amortization CalculatorOpen →
| Loan amount | Annual interest rate (APR) | Term | Show the split for year | Interest in the year shown |
|---|---|---|---|---|
| $16,745.08 |
Loan CalculatorOpen →
| Loan amount | Annual interest rate (APR) | Term | Extra monthly payment | Monthly payment |
|---|---|---|---|---|
| $512.91 |
Auto Loan CalculatorOpen →
| Vehicle price | Down payment | Trade-in value | Sales tax rate | Annual interest rate (APR) | Loan term | Monthly payment |
|---|---|---|---|---|---|---|
| $537.42 |
Credit Card Payoff CalculatorOpen →
| Card balance | Annual interest rate (APR) | Monthly payment | Time to pay off |
|---|---|---|---|
| 2 years 2 months |
Compound Interest CalculatorOpen →
| Starting balance | Annual interest rate | Years to grow | Compounding frequency | Monthly contribution | Final balance |
|---|---|---|---|---|---|
| $144,572.72 |
Savings Goal CalculatorOpen →
| Savings goal | Current savings | Monthly deposit | Annual return | Time to reach your goal |
|---|---|---|---|---|
| 4 years 10 months |
Retirement CalculatorOpen →
| Current age | Retirement age | Current retirement savings | Monthly contribution | Expected annual return | Safe withdrawal rate | Projected savings at retirement |
|---|---|---|---|---|---|---|
| $691,307 |
ROI CalculatorOpen →
| Initial investment | Final value | Holding period | Fees and costs | Return on investment |
|---|---|---|---|---|
| 48.0% |
Inflation CalculatorOpen →
| Amount today | Annual inflation rate | Number of years | Future cost |
|---|---|---|---|
| $18,061.11 |
Salary CalculatorOpen →
| Pay amount | Paid per | Hours per week | Paid weeks per year | Annual salary |
|---|---|---|---|---|
| $52,000 |
House Affordability CalculatorOpen →
| Gross annual income | Other monthly debt payments | Cash down payment | Mortgage interest rate | Loan term | Maximum home price |
|---|---|---|---|---|---|
| $392,243 |
Break-Even CalculatorOpen →
| Fixed costs | Price per unit | Variable cost per unit | Break-even volume |
|---|---|---|---|
| 2,000 units |
Net Worth CalculatorOpen →
| Cash & savings | Investments & retirement | Property market value | Other assets | Mortgage balance | Other debts | Net worth |
|---|---|---|---|---|---|---|
| $240,000 |
Sales Tax CalculatorOpen →
| Amount | Sales tax rate | Calculation | Sales tax |
|---|---|---|---|
| $8.25 |
Simple Interest CalculatorOpen →
| Principal | Annual interest rate | Term | Compare against compounding | Total interest |
|---|---|---|---|---|
| $3,000.00 |
APR CalculatorOpen →
| Loan amount | Quoted interest rate | Term | Discount points | Other upfront fees | APR |
|---|---|---|---|---|---|
| 6.695% |
Down Payment CalculatorOpen →
| Home price | Down payment | Closing costs | Moving & setup costs | Cash saved so far | Saving per month | Mortgage interest rate | Loan term | Cash needed up front |
|---|---|---|---|---|---|---|---|---|
| $75,000 |
Rent vs Buy CalculatorOpen →
| Home price | Rent you pay instead | Down payment | Mortgage rate | Rent rises by | Home appreciates by | Property tax, insurance & upkeep | Return on cash you would invest | Years until buying costs less |
|---|---|---|---|---|---|---|---|---|
| 6.8 years |
Refinance CalculatorOpen →
| Current loan balance | Current interest rate | Years left on your current loan | New interest rate | New loan term | Closing costs | Time to break even |
|---|---|---|---|---|---|---|
| 1 year 1 month |
Income Tax CalculatorOpen →
| Gross annual income | Filing status | Pre-tax deductions | Federal income tax |
|---|---|---|---|
| $9,870 |
Paycheck CalculatorOpen →
| Gross annual salary | Pay frequency | Federal filing status | Traditional 401(k) | Health premium per paycheck | Post-tax deductions per paycheck | Take-home pay per paycheck |
|---|---|---|---|---|---|---|
| $2,103.42 |
401(k) CalculatorOpen →
| Current age | Retirement age | Current 401(k) balance | Annual salary | Your contribution | Employer match rate | Match cap | Expected annual return | Annual pay rise | Projected 401(k) balance at retirement |
|---|---|---|---|---|---|---|---|---|---|
| $1,289,025 |
Budget CalculatorOpen →
| Monthly take-home pay | Housing | Transport | Groceries | Other essentials | Wants | Savings and extra debt repayment | Off the 50/30/20 split by |
|---|---|---|---|---|---|---|---|
| $900 |
Present Value CalculatorOpen →
| What do you want to work out? | Lump sum | Recurring payment | Payment and compounding frequency | Discount or growth rate | Number of years | Present value |
|---|---|---|---|---|---|---|
| $112,627.11 |
Car Lease CalculatorOpen →
| Negotiated price (capitalized cost) | Sticker price (MSRP) | Cash down (cap cost reduction) | Residual value at lease end | Money factor | Lease term | Monthly payment |
|---|---|---|---|---|---|---|
| $395.07 |
Mortgage Points CalculatorOpen →
| Rate with no points | Rate cut per point | Discount points bought | Loan amount | Loan term | Years you expect to keep this loan | Time to break even |
|---|---|---|---|---|---|---|
| 5 years 2 months |
Capital Gains Tax CalculatorOpen →
| Sale price | Cost basis | Selling costs | Holding period | Filing status | Other annual income | Federal capital gains tax |
|---|---|---|---|---|---|---|
| $2,925 |
Roth IRA CalculatorOpen →
| Current age | Retirement age | Annual Roth contribution | Expected annual return | Your tax rate now | Expected tax rate in retirement | Tax-free Roth balance at retirement |
|---|---|---|---|---|---|---|
| $1,036,777 |
Health & Fitness
BMI CalculatorOpen →
| Units | Weight | Height | Body mass index |
|---|---|---|---|
| 22.9 |
BMR CalculatorOpen →
| Units | Sex at birth | Weight | Height | Age | Basal metabolic rate |
|---|---|---|---|---|---|
| 1,649 kcal/day |
TDEE CalculatorOpen →
| Units | Sex | Weight | Height | Age | Activity level | Maintenance calories |
|---|---|---|---|---|---|---|
| 2,556 kcal/day |
Body Fat CalculatorOpen →
| Units | Sex at birth | Height | Neck circumference | Waist circumference | Hip circumference | Body weight | Body fat |
|---|---|---|---|---|---|---|---|
| 21.7% |
Ideal Weight CalculatorOpen →
| Units | Sex | Height | Ideal body weight |
|---|---|---|---|
| 70.0 kg |
Macro CalculatorOpen →
| Daily calorie target | Macro split | Daily protein |
|---|---|---|
| 150 g |
Water Intake CalculatorOpen →
| Units | Body weight | Exercise | Climate | Daily water target |
|---|---|---|---|---|
| 2.95 L |
Heart Rate Zone CalculatorOpen →
| Age | Resting heart rate | Estimated maximum heart rate |
|---|---|---|
| 190 bpm |
One Rep Max CalculatorOpen →
| Units | Weight lifted | Reps completed | Estimated one-rep max |
|---|---|---|---|
| 114.6 kg |
Running Pace CalculatorOpen →
| Distance | Distance unit | Hours | Minutes | Seconds | Pace |
|---|---|---|---|---|---|
| 5:00 |
VO2 Max CalculatorOpen →
| Field test | Units | Cooper test — distance in 12 minutes | 1.5-mile run — finishing time | Rockport walk — time for 1 mile | Rockport walk — heart rate at the finish | Maximum heart rate | Resting heart rate | Age | Sex at birth | Body weight | Estimated VO2 max |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 42.4 ml/kg/min |
Waist-to-Hip Ratio CalculatorOpen →
| Units | Sex at birth | Waist circumference | Hip circumference | Height | Waist-to-hip ratio |
|---|---|---|---|---|---|
| 0.86 |
Body Surface Area CalculatorOpen →
| Who is being measured | Height or length | Weight | Body surface area |
|---|---|---|---|
| 1.99 m² |
Lean Body Mass CalculatorOpen →
| Units | Sex at birth | Body weight | Height | Known body fat | Lean body mass |
|---|---|---|---|---|---|
| 60.9 kg |
Calories Burned CalculatorOpen →
| Units | Activity | Body weight | Duration | Calories burned |
|---|---|---|---|---|
| 237.0 kcal |
Math
Percentage CalculatorOpen →
| What do you want to work out? | Value A | Value B | Result |
|---|---|---|---|
| 50.0000 |
Percentage Change CalculatorOpen →
| Original value | New value | Percentage change |
|---|---|---|
| 50.00% |
Fraction CalculatorOpen →
| First numerator | First denominator | Operation | Second numerator | Second denominator | Simplified fraction |
|---|---|---|---|---|---|
| 5/6 |
Quadratic Equation CalculatorOpen →
| a (x² coefficient) | b (x coefficient) | c (constant term) | Roots |
|---|---|---|---|
| x = 4 or x = -1 |
Right Triangle CalculatorOpen →
| Leg a | Leg b | Hypotenuse |
|---|---|---|
| 5.000000 units |
Circle CalculatorOpen →
| Known measurement | That measurement is the… | Area |
|---|---|---|
| 314.159265 |
GCD & LCM CalculatorOpen →
| First number | Second number | Greatest common divisor |
|---|---|---|
| 12 |
Ratio CalculatorOpen →
| Term A | Term B | Term C | Missing term X |
|---|---|---|---|
| 12.0000 |
Area CalculatorOpen →
| Shape | Measurements are in | Dimension a — length, base, radius or semi-axis | Dimension b — width, height or second side | Height h — trapezoid only | Area |
|---|---|---|---|---|---|
| 192.00 ft² |
Volume CalculatorOpen →
| Solid | Dimensions are in | Diameter or length | Width | Height or side | Volume in litres |
|---|---|---|---|---|---|
| 1,696.5 L |
Probability CalculatorOpen →
| How are the two events related? | Probability of event A | Probability of event B | Number of independent trials | Probability both events happen |
|---|---|---|---|---|
| 6.00% |
Z-Score CalculatorOpen →
| Your value (x) | Mean of the distribution | Standard deviation | Z-score |
|---|---|---|---|
| 1.4000 |
Slope CalculatorOpen →
| First point x₁ | First point y₁ | Second point x₂ | Second point y₂ | Slope |
|---|---|---|---|---|
| 0.750000 |
Logarithm CalculatorOpen →
| Value (x) | Base (b) | Known logarithm (y) | Logarithm |
|---|---|---|---|
| 3 |
Combination & Permutation CalculatorOpen →
| Does the order of the picks matter? | Can the same item be picked more than once? | Items to choose from (n) | Items being chosen (r) | Number of ways |
|---|---|---|---|---|
| 120 |
Prime Number CalculatorOpen →
| Number to test | Is it prime? |
|---|---|
| No — 360 is composite |
Square Root CalculatorOpen →
| Number | Root degree (n) | Root |
|---|---|---|
| 8.485281 |
Exponent CalculatorOpen →
| Base (b) | Exponent (n) | Power |
|---|---|---|
| 1,024 |
Factorial CalculatorOpen →
| n — the number to take the factorial of | n factorial |
|---|---|
| 9332621544394415 … 0000000000000000 |
Distance CalculatorOpen →
| Kind of distance | Point A latitude | Point A longitude | Point B latitude | Point B longitude | Point A x | Point A y | Point A z | Point B x | Point B y | Point B z | Distance |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5,570.23 km |
Confidence Interval CalculatorOpen →
| Sample mean (x̄) | Standard deviation | Sample size (n) | Confidence level | Where the standard deviation came from | Confidence interval |
|---|---|---|---|---|---|
| 94.40 to 105.60 |
Half-Life CalculatorOpen →
| Solve for | Initial amount (N0) | Remaining amount (N) | Time unit | Elapsed time (t) | Half-life (T) | Amount remaining |
|---|---|---|---|---|---|---|
| 25 |
Everyday
Tip CalculatorOpen →
| Bill amount | Tip percentage | Number of people | Round each share up to a whole amount | Each person pays |
|---|---|---|---|---|
| $50.15 |
Unit ConverterOpen →
| Value to convert | What are you converting? | From | To | Converted value |
|---|---|---|---|---|
| 62.1371 mi |
Fuel Cost CalculatorOpen →
| Trip distance | Distance unit | Fuel efficiency | Efficiency unit | Fuel price | Price unit | Trip fuel cost |
|---|---|---|---|---|---|---|
| $14.40 |
Discount CalculatorOpen →
| Original price | Discount | Sales tax rate | Tax is charged on | Final price |
|---|---|---|---|---|
| $81.19 |
Electricity Cost CalculatorOpen →
| Appliance power | Hours used per day | Days used per month | Electricity rate | Cost per month |
|---|---|---|---|---|
| $20.40 |
Cooking Measurement ConverterOpen →
| Amount | From unit | To unit | Converted amount |
|---|---|---|---|
| 236.6 ml |
Paint CalculatorOpen →
| Units | Room length | Room width | Wall height | Doors | Windows | Coats | Coverage per unit of paint | Tin size | Price per tin | Paint needed |
|---|---|---|---|---|---|---|---|---|---|---|
| 7.71 L |
Concrete CalculatorOpen →
| What you are pouring | Units | Length — slab and footing only | Width — slab and footing only | Thickness — slab and footing only | Diameter — column and post hole only | Height or hole depth — column and post hole only | How many | Waste allowance | Concrete needed |
|---|---|---|---|---|---|---|---|---|---|
| 1.36 yd³ |
Tile CalculatorOpen →
| Units | Room length | Room width | Tile length | Tile width | Grout joint | Waste allowance | Tiles per box | Price per box | Tiles needed |
|---|---|---|---|---|---|---|---|---|---|
| 53 tiles |
Ohm's Law CalculatorOpen →
| Which two do you know? | Voltage (V) | Current (I) | Current unit | Resistance (R) | Resistance unit | Power (P) | Power unit | Current |
|---|---|---|---|---|---|---|---|---|
| 3.000 A |
Science
Trigonometry CalculatorOpen →
| Which do you know? | Angle unit | Angle θ | Ratio | sin θ |
|---|---|---|---|---|
| 0.500000 |
Triangle CalculatorOpen →
| What do you know? | Side a | Side b | Side c | Angle A | Angle B | Angle C | Side c |
|---|---|---|---|---|---|---|---|
| 4.950003 units |
Scientific Notation CalculatorOpen →
| What to do | Coefficient of A | Exponent of A (power of ten) | Coefficient of B | Exponent of B (power of ten) | Standard form |
|---|---|---|---|---|---|
| 6.02 × 10^23 |
Ideal Gas Law CalculatorOpen →
| Solve for | Pressure (P) | Pressure unit | Volume (V) | Volume unit | Amount of gas (n) | Temperature (T) | Temperature unit | Amount of gas |
|---|---|---|---|---|---|---|---|---|
| 1.0000 mol |
Molarity CalculatorOpen →
| What do you need? | Mass of solute | Molar mass | Solution volume | Volume unit | Molarity | Target molarity | Molarity |
|---|---|---|---|---|---|---|---|
| 1.0000 mol/L |
Kinematics CalculatorOpen →
| What do you want to find? | Initial velocity (u) | Acceleration (a) | Time (t) | Final velocity (v) | Displacement (s) | Displacement |
|---|---|---|---|---|---|---|
| 150.0000 m |
Vector CalculatorOpen →
| Operation | Dimensions | Vector a — x | Vector a — y | Vector a — z | Vector b — x | Vector b — y | Vector b — z | Dot product a · b |
|---|---|---|---|---|---|---|---|---|
| 11.000000 |
Engineering
Section Properties CalculatorOpen →
| Section | Units | Outer height, a | Outer width, b | Inner height, a₁ | Inner width, b₁ | Web / wall thickness, t | Flange thickness, tf | Number of sides, n | Angle | Outer diameter, D | Inner diameter, d | Second moment of area, Ix |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 49.280 × 10^6 mm⁴ |