Mathematics

Calculate the secondary voltage of an ideal transformer from its turns ratio — Vs = Vp × (Ns ÷ Np), in volts (V).

Calculate the area of a trapezoid (UK: trapezium) from its two parallel sides and the perpendicular height — area = ((a + b) / 2) × h.

Calculate the area of any triangle from its base and perpendicular height using the formula area = ½ × base × height.

Calculate the total surface area, lateral surface area, and cross-section area of a triangular prism from its three sides and length — uses Heron's formula.

Calculate the volume and cross-sectional area of a right triangular prism from its base, triangle height, and length — volume = ½ × base × height × length.

Work out the price per unit and the price per 100 units from a total price and quantity, so you can compare pack sizes and spot the better-value deal.

Calculate the magnitude (length) of a 3D vector, |v| = √(x² + y² + z²), from its x, y, and z components.

Calculate the output voltage of a two-resistor voltage divider — Vout = Vin × R₂ ÷ (R₁ + R₂), in volts (V).

Calculate the DC voltage drop (Vdrop = 2 × L × I × ρ / A) in volts and the power lost in a wire run from the current, length, resistivity, and cross-section.

Convert volume between metric, US customary, and UK imperial units — millilitres, centilitres, litres, cubic metres, US teaspoons, tablespoons, fluid ounces, cups, pints, quarts, US gallons, and UK gallons.

Calculate the volumetric flow rate (Q = A·v) in cubic metres per second and litres per second of a fluid from its cross-sectional area and velocity.

Convert watts and volts to amps and ohms instantly using Watt's law (I = P ÷ V) — useful for sizing fuses, cables, and circuit breakers for any DC or resistive AC load.

Convert watts to lumens by multiplying wattage by luminous efficacy (lm/W) — compare LED, CFL, halogen, and incandescent bulbs to estimate brightness from power consumption.

Calculate the wavelength and period of an electromagnetic wave from its frequency — wavelength = c ÷ f and period = 1 ÷ f.

Convert weight (mass) between metric and imperial units — milligrams, grams, kilograms, metric tonnes, ounces, pounds, and stone.

Calculate the weight (gravitational force, W = mg) on a mass in newtons from its mass and the local gravitational acceleration.

Find out what you would weigh on the Moon, Mars, Jupiter, and every other planet by scaling your Earth weight by each body's surface gravity.

Calculate the weighted average of two value and weight pairs — (v₁·w₁ + v₂·w₂) / (w₁ + w₂) — the classic grade- and score-weighting formula.

Calculate your weighted grade average in percent — give each grade a share, all shares should add up to 100%. Dynamically supports 2–8 grades.

Convert a battery energy in watt-hours to charge capacity in milliamp-hours by dividing by the nominal voltage — useful for reading power-bank spec sheets and airline limit labels.

Find the unknown resistance of a balanced Wheatstone bridge from its three known resistors — Rx = (R2 × R3) / R1.

Calculate the peak emission wavelength of a blackbody (λ_max = b/T) in metres and nanometres from its absolute temperature using Wien's displacement law.

Calculate the wind chill (feels-like) temperature in degrees Celsius from the air temperature and wind speed using the official NWS metric formula.

Calculate the power output of a wind turbine (P = ½ρAv³Cp) in watts from the air density, rotor swept area, wind speed, and power coefficient.

Calculate the electrical resistance (R = ρL/A) in ohms of a wire from its resistivity, length, and cross-sectional area.

Estimate how many pages your word count fills for common font sizes and line spacings, with single- and double-spaced results shown clearly.

Calculate the mechanical work done by a force over a distance — work = force × distance × cos(θ), measured in joules.