All calculators
Financial
- Mortgage CalculatorCalculate your monthly mortgage payment including principal, interest, taxes, insurance, and PMI. Supports 10, 15, 20, and 30-year fixed loans.
- Amortization CalculatorSee how each loan payment splits between principal and interest, year by year, and exactly when principal finally overtakes interest.
- 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.
- Auto Loan CalculatorWork out your monthly car payment from price, down payment, trade-in, sales tax, and APR, and see the total interest over the full loan term.
- Credit Card Payoff CalculatorSee how long a fixed monthly payment takes to clear your credit card balance, and how much of that money goes to interest rather than the debt.
- Compound Interest CalculatorSee what your savings grow to with compound interest and monthly contributions. Choose annual, quarterly, monthly, or daily compounding.
- Savings Goal CalculatorWork out how long it takes to reach a savings target from your current balance, monthly deposit, and interest rate, with compounding month by month.
- Retirement CalculatorProject your retirement savings from your current balance, monthly contributions, and expected return, then see the yearly income the 4% rule allows.
- ROI CalculatorWork out return on investment from what you put in, what it is worth now, and the fees — plus the annualized rate over your holding period.
- Inflation CalculatorSee what today's money will cost in the future, and how much purchasing power inflation quietly erases over 5, 10, 20, or 30 years.
- Salary CalculatorConvert pay between hourly, daily, weekly, biweekly, monthly, and annual figures. Set your hours per week and paid weeks per year for an exact match.
- House Affordability CalculatorFind out how much house you can afford using the 28/36 rule. Enter income, debts, down payment, and rate to see your maximum home price.
- Break-Even CalculatorFind how many units you must sell to cover costs. Calculates break-even volume, break-even revenue, and contribution margin per unit and as a percent.
- Net Worth CalculatorAdd up cash, investments, property, and debts to see your net worth, home equity, and debt-to-asset ratio in a single snapshot.
- Sales Tax CalculatorAdd sales tax to a price, or work backwards to pull the tax out of a tax-inclusive total. Shows the pre-tax amount, the tax, and the final total.
- Simple Interest CalculatorWork out simple interest with I = P × r × t and the total amount, then see exactly how far compound interest pulls ahead on the very same terms.
- APR CalculatorFind the true annual cost of a loan once points and fees are counted, and see how far the APR sits above the rate you were quoted.
- Down Payment CalculatorWork out the cash you need up front to buy a home — down payment, closing costs and moving — plus the loan it leaves, the monthly payment, and PMI.
- Debt Payoff CalculatorCompare the debt snowball and the debt avalanche on your own balances. See when you are debt-free either way, and what the cheaper order actually saves.
- Rent vs Buy CalculatorCompare renting against buying over 30 years — mortgage, tax, upkeep, appreciation and the opportunity cost of your deposit — and find the break-even year.
- Refinance CalculatorWork out your refinance break-even month, the monthly saving, and whether a fresh loan term quietly adds more interest than the lower rate saves.
- Income Tax CalculatorWork out 2026 US federal income tax bracket by bracket, and see why the effective rate you pay is well below the marginal rate on your last dollar.
- Paycheck CalculatorEstimate take-home pay per paycheck for 2026 after federal income tax, Social Security, Medicare, 401(k) and health premiums. Federal only, no state tax.
- 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.
- Budget CalculatorCompare your monthly spending against the 50/30/20 rule and see exactly how many dollars in each category are above or below the guideline.
- Present Value CalculatorWork out what a future payout or a stream of payments is worth today, or what money today grows to, with the discount factor and every step shown.
- NPV CalculatorDiscount a project’s cash flows to today to get its net present value, the IRR it really earns, and how long the money takes to come back.
- Car Lease CalculatorWork out a car lease payment from cap cost, residual and money factor — and see the APR that money factor is quietly standing in for.
- Mortgage Points CalculatorWork out whether discount points are worth buying: the up-front cost, the monthly saving, the break-even month, and whether you keep the loan that long.
- Capital Gains Tax CalculatorWork out 2026 federal capital gains tax on a sale and see the short-term and long-term bills side by side, whatever your holding period.
- 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.
Health & Fitness
- 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.
- BMR CalculatorCalculate your basal metabolic rate with the Mifflin-St Jeor equation in metric or imperial units, and see daily calorie needs at four activity levels.
- TDEE CalculatorEstimate your total daily energy expenditure from height, weight, age, sex and activity level, plus the intake for losing or gaining weight.
- Body Fat CalculatorEstimate your body fat percentage with the US Navy tape method from height, neck, waist and hip measurements, in centimetres or inches.
- Ideal Weight CalculatorFind your ideal body weight from height and sex using the Devine, Robinson, Miller and Hamwi formulas, plus your healthy BMI weight range.
- Macro CalculatorTurn a daily calorie target into grams of protein, carbohydrate, and fat using a balanced, low-carb, or high-carb split. Shows the calories behind each macro.
- Water Intake CalculatorWork out how much water to drink each day from your body weight, exercise, and climate — in litres, millilitres, cups, and glasses.
- Heart Rate Zone CalculatorWork out your five heart rate training zones with the Karvonen method, using your age and resting pulse to set a target bpm range for every effort.
- One Rep Max CalculatorEstimate your one-rep max from a submaximal set using the Epley and Brzycki formulas, plus percentage training loads in kilograms or pounds.
- Running Pace CalculatorTurn a run distance and finishing time into pace per kilometre or mile, speed in km/h and mph, and predicted 5K, 10K, half and marathon times.
- Due Date CalculatorEstimate a due date from the last menstrual period using Naegele’s rule, adjusted for cycle length, with gestational age, trimester and milestones.
- VO2 Max CalculatorEstimate VO2 max from a Cooper 12-minute run, a 1.5-mile run, a Rockport walk test or your resting pulse, and see the fitness category for your age and sex.
- Waist-to-Hip Ratio CalculatorDivide your waist by your hips to see where you carry fat, check it against the WHO cut-offs of 0.90 and 0.85, and get your waist-to-height ratio.
- Body Surface Area CalculatorCalculate body surface area in m² from height and weight using the Mosteller, Du Bois, Haycock, Gehan & George and Boyd formulas side by side.
- Lean Body Mass CalculatorEstimate lean body mass from height, weight and sex with the Boer, James and Hume formulas side by side, plus fat mass and fat-free mass index.
- Ovulation CalculatorEstimate your ovulation date and six-day fertile window from your last period and cycle length, counted back from the next period rather than forward.
- Calories Burned CalculatorWork out the calories burned in one session from its MET value, your body weight and its length — with the gross and net figures shown separately.
- Caloric Deficit CalculatorTurn maintenance calories and a goal weight into a daily intake, a weekly rate and a date — with the 3,500-calorie rule shown against a model that adapts.
Math
- Percentage CalculatorWork out what X% of a number is, what percent one number is of another, and any percentage increase or decrease, with every step shown.
- Percentage Change CalculatorFind the percentage increase or decrease between two numbers, with the absolute difference, direction, and multiplier worked out step by step.
- Fraction CalculatorAdd, subtract, multiply or divide two fractions and see the answer reduced to lowest terms, plus the mixed number and decimal equivalents.
- Average CalculatorPaste a list of numbers to get the mean, median, mode, range, minimum, maximum, count, and both sample and population standard deviation.
- Quadratic Equation CalculatorSolve any quadratic equation ax² + bx + c = 0 with the quadratic formula. Shows real or complex roots, the discriminant, the vertex, and the axis of symmetry.
- Right Triangle CalculatorEnter the two legs of a right triangle to get the hypotenuse, area, perimeter and both acute angles in degrees, with every step shown.
- Circle CalculatorEnter any one circle measurement — radius, diameter, circumference or area — and get the other three instantly, with every step of the working shown.
- GCD & LCM CalculatorFind the greatest common divisor and least common multiple of two whole numbers, with the full Euclidean algorithm and prime factorisation shown.
- Ratio CalculatorSimplify a ratio to its lowest terms and solve the proportion A : B = C : X for the missing value, with the decimal form and percentage split.
- Area CalculatorFind the area of a rectangle, triangle, circle, trapezoid, parallelogram or ellipse, converted into square feet, square metres, acres and more.
- Volume CalculatorWork out the volume of a box, cylinder, sphere, cone, capsule or pyramid, and read it off in litres, cubic metres, cubic feet and gallons.
- Probability CalculatorFind P(A and B), P(A or B), P(neither) and the complements for two events, independent or mutually exclusive, plus the odds of it happening at least once.
- Z-Score CalculatorFind the z-score of a value from the mean and standard deviation, then see its percentile, the area in each tail, and the two-tailed p-value.
- Slope CalculatorFind the slope between two points, with the line equation, y-intercept, angle, distance, midpoint, and the percentage grade and ratio builders use.
- Logarithm CalculatorWork out log to any base, with log10, ln and log2 shown alongside. Includes the change-of-base formula, a b^y check, and the inverse antilogarithm.
- Combination & Permutation CalculatorWork out nCr and nPr — how many ways to choose or arrange r items from n, with or without repetition — and see which of the four formulas your question needs.
- Prime Number CalculatorCheck whether a number is prime, see its prime factorisation in exponent form, list every divisor, and find the nearest primes above and below it.
- Square Root CalculatorFind the square root or any nth root, in simplified radical form as well as decimal. √72 = 6√2, with the perfect-square factor extraction shown step by step.
- Exponent CalculatorWork out b to the power n for any base and exponent, including negative, fractional and zero powers, with the answer in scientific notation.
- Factorial CalculatorWork out n! exactly, with every digit, up to 10,000!. Shows the full integer, its digit count, scientific notation and how many zeros it ends in.
- Distance CalculatorDistance between two latitude and longitude points by the haversine formula, in km and miles, plus 3D straight-line and Manhattan taxicab distance.
- Confidence Interval CalculatorBuild a confidence interval for a mean from the sample mean, standard deviation and size. Uses Student’s t when σ is estimated, z when it is known.
- Half-Life CalculatorSolve exponential decay in any direction — remaining amount, half-life, elapsed time or starting amount — with the decay constant and mean lifetime.
Everyday
- Tip CalculatorWork out the tip, the total, and what each person owes. Enter the bill, a tip percentage, and party size, and optionally round every share up.
- Age CalculatorFind your exact age in years, months and days from any birth date, plus total days, weeks and months lived and a countdown to your next birthday.
- Date Difference CalculatorCount the days, weeks, business days, months and years between two dates, with an option to include the end date in the total.
- Unit ConverterConvert length, weight, and temperature units — metres to miles, kilograms to pounds, Celsius to Fahrenheit — with the exact factors shown.
- Fuel Cost CalculatorWork out what fuel a trip will cost from distance, efficiency and pump price. Handles km or miles and L/100km, km/L or mpg, plus the round trip.
- Discount CalculatorWork out the sale price after a percentage discount, how much you save, and what sales tax adds. Handles tax charged before or after the discount.
- Electricity Cost CalculatorWork out what any appliance costs to run. Enter its wattage, hours used per day, and your rate per kWh to see the daily, monthly, and yearly cost.
- Cooking Measurement ConverterConvert cups, tablespoons, teaspoons, fluid ounces, millilitres, litres, pints and quarts. Enter one amount and read every other kitchen measure.
- GPA CalculatorWork out your term and cumulative GPA from a list of courses and credit hours, on either the standard 4.0 scale or a weighted 5.0 AP and honours scale.
- Paint CalculatorWork out how much paint a room needs from its size, coats and coverage. Deducts doors and windows, rounds tins up, and totals what you will pay.
- Business Days CalculatorCount working days between two dates, or add business days to a date. Skips weekends and US federal holidays, including their observed days.
- Concrete CalculatorWork out concrete for a slab, footing, column or post holes in cubic yards and cubic metres, then how many 40, 60 or 80 lb bags to buy.
- Tile CalculatorWork out how many tiles a floor or wall needs by laying them out row by row, not by dividing area — plus boxes to buy, waste allowance and total cost.
- Grade CalculatorFind the score you need on your final exam to hit a target grade, plus your current weighted grade and the best and worst grades still possible.
- Time Zone ConverterConvert a date and time between two time zones. Shows the local time, whether it lands on the next or previous day, both UTC offsets and the gap.
- Ohm's Law CalculatorEnter any two of voltage, current, resistance and power and get the other two, with the formulas used shown. Handles short and open circuits properly.
- Time Card CalculatorAdd up a week of clock-in and clock-out times, subtract unpaid breaks, split regular from overtime hours, and multiply by your hourly rate.
Science
- Trigonometry CalculatorSine, cosine, tangent and their reciprocals for any angle in degrees, radians or gradians — or work back to the angle with arcsin, arccos and arctan.
- Triangle CalculatorSolve any triangle from three known parts — SAS, SSS, ASA, AAS or SSA. Returns every side and angle, the area, the perimeter, and both ambiguous answers.
- Significant Figures CalculatorCount the significant figures in any number, or round to a set number of them, with every rule shown — leading, trailing and embedded zeros included.
- Scientific Notation CalculatorWrite a number in standard form, or multiply, divide, add and subtract in scientific notation — with the significant-figure rule for each shown in full.
- Ideal Gas Law CalculatorEnter any three of pressure, volume, moles and temperature and get the fourth from PV = nRT, in atm, kPa, bar, mmHg, psi and K, °C or °F.
- Molarity CalculatorWork out molarity from a mass, the mass to weigh out for a target concentration, the volume to make up to, or a dilution using M₁V₁ = M₂V₂.
- Kinematics CalculatorSolve for displacement, final velocity, acceleration or time with the SUVAT equations, with every step shown and the motion plotted against time.
- Vector CalculatorDot and cross product, angle between two vectors, magnitude, unit vector, projection, addition and subtraction, in 2D or 3D, with the working shown.
- Matrix CalculatorDeterminant, inverse, transpose, product, sum or difference of a 2 x 2 or 3 x 3 matrix, with the cofactor expansion and the adjugate written out.
- Linear Regression CalculatorFit a least-squares line to your x and y data, predict y at any x, and see the slope, intercept, r, R² and standard error worked out step by step.