Percentage
Calculate what x% of y is, what percentage a is of b, and the percentage change from A to B.
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Everyday numbers
Unit and currency converters, dates and hours, trip fuel, car running costs (TCO), breathalyzer, and school math and physics.
Percentage change
Calculate the percentage increase or decrease from a starting value to a new value.
Open calculatorTrigonometry (sin, cos, tan)
Calculate sine, cosine, tangent and radian measure for an angle in degrees.
Open calculatorPythagorean theorem
Enter any two sides of a right triangle and the calculator solves for the third side and triangle area.
Open calculatorQuadratic equation
Find the discriminant (Δ) and real roots (x₁, x₂) of a quadratic equation ax² + bx + c = 0.
Open calculatorLogarithm
Calculate log_b(x) for any valid base, alongside the natural logarithm (ln) and common base-10 logarithm (log₁₀).
Open calculatorCombinatorics (n!, nPr, nCr)
Calculate factorial (n!), permutations without repetition (nPr) and combinations (nCr) for whole numbers.
Open calculatorGCD and LCM
Find the greatest common divisor (GCD) and least common multiple (LCM) of two integers.
Open calculatorCircle area & circumference
Calculate diameter, circumference and area of a circle from its radius.
Open calculatorTriangle area (Heron’s formula)
Calculate the area and semi-perimeter of any valid triangle from the lengths of its three sides.
Open calculatorOhm’s law & electrical power
Enter any two of the four quantities (voltage, current, resistance, power) to calculate the remaining two values.
Open calculatorNewton’s second law (F = m·a)
Leave one of force, mass or acceleration empty to solve for the missing SI value.
Open calculatorKinetic & potential energy
Calculate translational kinetic energy and gravitational potential energy in joules (J).
Open calculatorFree fall
Starting from rest in a vacuum: enter either fall time or drop distance and leave the other field blank.
Open calculatorIdeal gas law (PV = nRT)
Leave one of pressure (P), volume (V), moles (n) or temperature (T) blank to solve the ideal gas equation.
Open calculatorWave speed (v = f · λ)
Leave one of wave speed, frequency or wavelength blank to calculate the missing value.
Open calculatorDensity, mass & volume
Leave one of mass, volume or density blank to solve ρ = m / V.
Open calculatorSnell’s law of refraction
Calculate the angle of refraction across an optical boundary (n₁, n₂) or check for total internal reflection.
Open calculatorThin-lens equation
Leave one of focal length (f), object distance (u) or image distance (v) blank to solve for the third value and magnification.
Open calculatorUnit converter
Weight, length, distance and temperature. Convert common metric and imperial units instantly.
Open calculatorCurrency
Euro, zloty, US dollar and other ECB currencies using the reference rate from the latest TARGET business day.
Open calculatorExact age
Calculate your exact chronological age today in full years, months and days from your date of birth.
Open calculatorDays between dates
Count calendar days, weeks and weekdays (Mon–Fri) between two dates, or add/subtract days from a start date.
Open calculatorHours & work time
Calculate hours and minutes between two clock times minus a break, or add minutes to a starting time.
Open calculatorPolish workdays
Count working days between two dates (excluding weekends and Polish public holidays) or add working days to a start date.
Open calculatorTrip fuel cost
Calculate fuel required in litres and total trip cost from distance, fuel consumption (L/100 km) and pump price.
Open calculatorCommute cost
Compare the monthly cost of driving to work (fuel and parking) against a monthly public-transit pass.
Open calculatorCar running cost (TCO)
Calculate the true annual car running cost and total car cost per year, month and kilometre (TCO), including depreciation, fuel, insurance and maintenance.
Open calculatorCar lease payment
Estimate a lease payment and total cost including buyout and fees. Enter your own terms or start from a documented offer and vehicle price on a selected date.
Open calculatorBreathalyzer (Widmark BAC)
Log drinks with clock times to estimate blood-alcohol concentration (‰) at a chosen readout hour using the Widmark model.
Open calculatorAlcohol Units and Grams
Calculate pure ethyl alcohol in grams, standard drinks (10 g), UK units, and alcohol calories.
Open calculatorDriving time
Calculate travel time in hours and minutes from trip distance and average speed.
Open calculatorMonthly fuel cost
Calculate how many litres of fuel you burn and your monthly pump bill from monthly mileage.
Open calculatorRecipe scaler
Scale an ingredient amount up or down from the recipe’s original yield to the number of servings you want.
Open calculatorUnit price comparison
Compare two pack sizes by price per unit (gram, millilitre or piece) and see which one is cheaper in percent.
Open calculatorWall paint needed
Calculate how many litres of paint you need from wall area, number of coats and tin coverage (m²/L).
Open calculatorFlooring & tile packs
Calculate how many packs of laminate, wood flooring or tiles to buy from room area, cutting waste and pack coverage.
Open calculatorDew point
Calculate the Magnus dew-point temperature from air temperature and relative humidity.
Open calculatorWind chill
Calculate how cold the air feels on exposed skin from air temperature and wind speed.
Open calculatorWallpaper rolls needed
Calculate how many wallpaper rolls to buy from wall perimeter, room height, roll dimensions and pattern-matching waste.
Open calculatorConcrete slab volume
Calculate cubic metres (m³) of concrete needed for a rectangular slab or screed, including a waste margin.
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