All Calculators
Every one of the 1678 tools on the site, grouped by what they do. All free, no sign-up.
Finance
147Loan & EMI Calculator
Monthly payment, total interest, and a full amortization schedule.
OpenMortgage Calculator
Full monthly cost including tax, insurance, and PMI.
OpenCompound Interest Calculator
See how savings grow with regular contributions.
OpenSIP Calculator
Project returns on a monthly investment plan.
OpenDiscount Calculator
Final price after one or two discounts, plus tax.
OpenTip Calculator
Tip amount and per-person split, rounded cleanly.
OpenCar Affordability Calculator
Worked back from income, with running costs taken out first.
OpenAuto Refinance Calculator
The monthly saving, against what it costs over the life.
OpenCar Lease Calculator
Depreciation fee plus finance fee, with the money factor converted.
OpenCar Loan Payoff Calculator
What an extra payment each month actually removes.
OpenBiweekly Car Payment Calculator
Twenty-six half payments is thirteen monthly ones.
OpenLease Buyout Calculator
The residual was fixed years ago; the car has an opinion now.
OpenBalloon Payment Calculator
The payment is lower because the principal is still there.
OpenCar Equity Calculator
What the car is worth against what you still owe.
OpenCar Loan Debt-to-Income Calculator
The ratio the lender computes, before they compute it.
OpenCar Cost of Ownership Calculator
Depreciation is the biggest cost and never appears on a statement.
OpenNPV Calculator
Uneven cash flows, with period zero left undiscounted.
OpenIRR Calculator
The rate where NPV hits zero, found by bisection.
OpenPresent Value Calculator
A lump sum, a level stream, or both.
OpenDiscount Factor Calculator
The multiplier, period by period, with the annuity factor.
OpenDiscount Rate Calculator
The rate implied by two amounts, and the two conventions for it.
OpenWACC Calculator
Where the discount rate comes from, tax shield included.
OpenDiscounted Payback Period Calculator
When the money comes back, once the wait is priced in.
OpenDCF Valuation Calculator
Forecast, terminal value, and how much of the answer it is.
OpenBMI Calculator
Body mass index with category and healthy weight range.
OpenCalorie & BMR Calculator
Daily calorie needs for losing, holding, or gaining weight.
OpenBody Fat Calculator
Body fat percentage from tape measurements.
OpenIdeal Weight Calculator
Target weight from four clinical formulas plus BMI range.
OpenPregnancy Due Date Calculator
Due date, current week, and trimester milestones.
OpenWater Intake Calculator
Daily hydration target adjusted for exercise and climate.
OpenLean Body Mass Calculator
Everything you weigh that is not fat.
OpenFFMI Calculator
Fat-free mass index, muscularity adjusted for height.
OpenWaist-to-Hip Ratio Calculator
Where you carry fat, and what the WHO says about it.
OpenWaist-to-Height Ratio Calculator
Keep your waist under half your height.
OpenBody Surface Area Calculator
BSA by Du Bois, Mosteller, Haycock and Boyd.
OpenBMI Prime Calculator
Your BMI as a simple ratio to the upper healthy limit.
OpenPonderal Index Calculator
A leanness index that handles very tall and short people better.
OpenAdjusted Body Weight Calculator
Ideal, actual and adjusted weight for dosing.
OpenBody Adiposity Index Calculator
Body fat estimated from hip size and height, no weight needed.
OpenSkinfold Body Fat Calculator
Jackson-Pollock 3-site caliper method.
OpenBMR Calculator
Basal metabolic rate by three formulas, side by side.
OpenTDEE Calculator
Total daily energy expenditure and what each part contributes.
OpenMacro Calculator
Protein, fat and carbs in grams for your goal.
OpenProtein Intake Calculator
Daily protein target for your body weight and goal.
OpenCalorie Deficit Calculator
How big a deficit gives the rate of loss you want.
OpenGoal Weight Date Calculator
When you will reach your target weight at your current rate.
OpenCalories Burned Calculator
Energy cost of an activity from its MET value.
OpenCarb Calculator
Daily carbohydrate target, including a low-carb option.
OpenEtsy Fee Calculator
Every Etsy fee on one sale, itemised.
OpenEtsy Profit Calculator
What you keep after fees, materials and shipping.
OpenEtsy Seller Fee Calculator
Total seller cost across a month of orders.
OpenEtsy Listing Fee Calculator
Publishing and renewal costs across your catalogue.
OpenEtsy Transaction Fee Calculator
The 6.5% cut, including on the shipping you charge.
OpenEtsy Payment Processing Fee Calculator
Card processing by market, percentage plus a flat charge.
OpenEtsy Offsite Ads Fee Calculator
The 12-15% commission, and the per-order cap.
OpenEtsy Ads Budget Calculator
What a daily budget buys, and the ACOS it needs to work.
OpenEtsy Net Profit Calculator
Monthly profit after fees, costs and fixed overheads.
OpenEtsy Take-Home Pay Calculator
What reaches your bank after fees and tax set-aside.
OpenEtsy Fee Calculator with VAT
Fees, VAT on fees, and VAT on sales, kept separate.
OpenEtsy Fee Calculator UK
UK rates, in pounds, with the regulatory operating fee.
OpenEtsy Fee Calculator Canada
Canadian rates in CAD, with GST/HST handling.
OpenEtsy Fee Calculator Australia
Australian rates in AUD, with GST on fees.
OpenEtsy Fee Calculator India
Indian seller fees in rupees, with GST.
OpenEtsy Fee Calculator Germany
German rates in euros, with 19% VAT and the regulatory fee.
OpenEtsy Regulatory Operating Fee Calculator
The country-specific surcharge on every order.
OpenEtsy Currency Conversion Fee Calculator
The 2.5% cost of listing and banking in different currencies.
OpenEtsy Plus Break-Even Calculator
Whether the subscription credits cover the subscription.
OpenEtsy Fee vs Profit Calculator
Who keeps more of the sale; you or Etsy?
OpenGross Profit Margin Calculator
Revenue minus cost of goods, as a percentage.
OpenNet Profit Margin Calculator
What survives after every cost, as a percentage.
OpenOperating Margin Calculator
Profit from operations, before interest and tax.
OpenContribution Margin Calculator
What each sale contributes toward fixed costs.
OpenRing Size Calculator
Finger measurement to US, UK, EU and Japanese sizes.
OpenRing Size Conversion Calculator
Convert a known ring size between countries.
OpenShoe Size Conversion Calculator
US, UK, EU, Japan and centimetres, from one measurement.
OpenMen's Shoe Size Calculator
Men's sizing from a foot measurement in centimetres.
OpenWomen's Shoe Size Calculator
Women's sizing from a foot measurement in centimetres.
OpenKids' Shoe Size Calculator
Children's sizing, with growing room built in.
OpenShoe Width Calculator
Width letter from the girth around the ball of the foot.
OpenBra Size Calculator
Band and cup from two measurements, UK and US.
OpenSister Size Calculator
Same cup volume, different band.
OpenBra Size Conversion Calculator
UK, US, European and Australian bra sizes.
OpenHat Size Calculator
Head circumference to US, UK and European hat sizes.
OpenGlove Size Calculator
Hand circumference to numeric and letter sizes.
OpenBelt Size Calculator
Belt length from your trouser waist.
OpenFabric Yardage Calculator
How much to buy, from your pieces and the bolt width.
OpenFabric Width Conversion Calculator
Yardage when the bolt is a different width.
OpenFabric Shrinkage Calculator
Cut length that survives the first wash.
OpenGSM to oz/yd² Calculator
Fabric weight between metric and imperial.
OpenFabric Weight Calculator
What a cut of fabric actually weighs.
OpenSeam Allowance Calculator
Cut size from finished size, and back again.
OpenBias Binding Calculator
Continuous bias strip yield from a square.
OpenHalf Square Triangle Calculator
Cut size for HST units, and how many squares.
OpenFat Quarter Calculator
What a fat quarter actually yields.
OpenQuilt Backing Calculator
Backing yardage, with overhang and panel seams.
OpenQuilt Binding Calculator
Strips to bind a quilt, and the yardage they take.
OpenPercentage Calculator
Every common percentage question in one place.
OpenAge Calculator
Exact age in years, months, days, and total units.
OpenDate Difference Calculator
Days between two dates, with or without weekends.
OpenGPA Calculator
Weighted GPA from course grades and credit hours.
OpenFraction Calculator
Add, subtract, multiply, and divide fractions.
OpenAverage Calculator
Mean, median, mode, range, and standard deviation.
OpenZ-Score Calculator
Standard deviations from the mean, and the percentile that follows.
OpenConfidence Interval Calculator
The range around an estimate, for a mean or a proportion.
OpenSample Size Calculator
How many responses a target margin of error actually costs.
OpenProbability Calculator
Two events combined, and the odds over repeated trials.
OpenPermutation and Combination Calculator
nPr and nCr, with and without repetition.
OpenDay of the Week Calculator
What day any date falls on, past or future.
OpenWeek Number Calculator
ISO 8601 week numbers, including the year-boundary cases.
OpenFinal Grade Calculator
The score you need on the final, and whether it is reachable.
OpenCircle Calculator
Area, circumference, radius and diameter from any one of them.
OpenCircle Sector Calculator
Sector area, arc length and chord from a radius and an angle.
OpenArc Length Calculator
Arc length and chord, with the radian conversion shown.
OpenEllipse Calculator
Area exactly, perimeter by Ramanujan's approximation.
OpenPythagorean Theorem Calculator
The missing side of a right triangle, plus its angles and area.
OpenTrapezoid Calculator
Area from the two bases and the height, with the midsegment.
OpenSphere Calculator
Volume and surface area, and why one is the derivative of the other.
OpenCube Calculator
Volume, surface area and the space diagonal.
OpenRectangular Prism Calculator
Box volume, surface area and the diagonal that decides what fits.
OpenCylinder Calculator
Volume, surface area, and the label that peels off flat.
OpenSpeed Distance Time Calculator
Any one of the three from the other two, in four units.
OpenVelocity Calculator
Final velocity under constant acceleration, with the distance.
OpenAcceleration Calculator
Acceleration in m/s² and in g, which is the legible one.
OpenFree Fall Calculator
Fall speed and time, with the air resistance caveat stated.
OpenProjectile Motion Calculator
Range, height and flight time, and why 45° is optimal.
OpenForce Calculator
F = ma, in newtons, kilograms-force and pounds-force.
OpenKinetic Energy Calculator
½mv², and why doubling speed quadruples the damage.
OpenPotential Energy Calculator
mgh, and how little food energy lifting actually costs.
OpenWork Calculator
W = Fd cos θ, including the case that comes out zero.
OpenPower Calculator
Watts, kilowatts and horsepower, with a running cost.
OpenMomentum Calculator
Momentum, impulse, and the principle behind crumple zones.
OpenTorque Calculator
Turning force, in newton-metres and pound-feet.
OpenDensity Calculator
Density, mass or volume, and whether it floats.
OpenPressure Calculator
From a force on an area, or from a depth of fluid.
OpenResistor Calculator
Series and parallel totals for up to four resistors.
OpenCapacitor Calculator
Series and parallel, which are the reverse of resistors.
OpenVoltage Divider Calculator
Output voltage, current and the power each resistor dissipates.
OpenLED Resistor Calculator
The series resistor, rounded up to a standard value.
OpenBattery Life Calculator
Runtime with a derating factor, because the ideal figure never happens.
OpenTransformer Calculator
Turns ratio, secondary voltage and current, with power conserved.
OpenRC Time Constant Calculator
τ = RC, with the charging percentages and the filter cutoff.
OpenInductance Calculator
Reactance at frequency, and where L and C cancel.
OpenPower Factor Calculator
Real against apparent power, and the current it costs.
OpenMolarity Calculator
Moles per litre of solution — not of solvent.
Open