Calculators
Most of Nerdulator answers a single value. These need two or three, so they live here instead of at their own URL. They are still server-rendered, still deterministic, and every result is linkable, because the inputs live in the query string.
23 calculators, tagged with what each one covers. Everything answerable from a single value lives on a page of its own instead; the engines page lists those.
reference
Tempo, beat length and delay times
Convert a tempo in beats per minute into note lengths and delay times, including dotted and triplet subdivisions.
- BPM to milliseconds
- Note durations
- Dotted and triplet delays
- Tempo markings
Surface gravity and escape velocity
Work out the surface gravity, escape velocity and orbital speed for a body of a given mass and radius, and what a given mass would weigh on it.
- Surface gravity
- Escape velocity
- Low orbit speed
- Weight on another world
Relativistic time dilation and length contraction
The Lorentz factor, time dilation, length contraction and relativistic mass increase for an object moving at a given fraction of the speed of light.
- Lorentz factor
- Time dilation
- Length contraction
- Relativistic energy
BMI, body surface area and resting metabolic rate
Body mass index, body surface area and basal metabolic rate from height, weight and age. Population formulas, not medical advice.
- Body mass index
- BMI category
- Body surface area
- Basal metabolic rate
Compound interest and growth
Compound growth of a starting amount at a fixed rate, with optional regular contributions, plus the doubling time and the effective annual rate.
- Compound interest
- Effective annual rate
- Doubling time
- Regular contributions
maths
Percentage change
The change from one value to another, as a percentage, a multiplier and a difference.
- Percentage change
- Percentage increase/decrease
Combinations and permutations
How many ways to choose or arrange k items from n, with and without repetition.
- Permutations
- Combinations
- Factorials
Probability of repeated events
Independent trials: at least one success, no successes, and expected counts.
- Probability
Quadratic equation solver
Solves ax² + bx + c = 0 exactly, including complex roots.
- Basic algebra
- Roots
Greatest common divisor and lowest common multiple
GCD, LCM and the relationship between them for two integers.
- GCD
- LCM
- Ratios
Mean, median, mode and standard deviation
Summary statistics for a list of numbers, including quartiles and outliers.
- Mean
- Median
- Mode
- Range
- Standard deviation
Logarithms, powers and roots
Logarithms in any base, plus the matching power and root for the same pair of numbers.
- Logarithms
- Powers
- Roots
science
Speed, distance and time
Leave any one of the three blank or zero and it is solved for. All three rearrangements of v = d / t.
- Speed = distance/time
- Distance = speed x time
- Time = distance/speed
Kinetic energy
Kinetic energy from mass and velocity, with the equivalents in everyday units.
- Kinetic energy
Gravitational potential energy
Potential energy from mass and height at standard Earth gravity.
- Potential energy
Ohm's law and electrical power
Voltage, current, resistance and power. Enter any two, get the rest.
- Ohm's law
- Electrical power
Wavelength and frequency
Convert between the wavelength, frequency and photon energy of an electromagnetic wave.
- Frequency/wavelength
Ideal gas law
PV = nRT. Find the pressure of a given amount of gas at a given volume and temperature.
- Ideal gas calculations
Radioactive decay and half-life
How much of a sample remains after a given time, given its half-life.
- Half-life calculations
pH and hydrogen ion concentration
Convert between pH, pOH and molar concentration at 25 °C.
- Basic pH calculations
Pressure from force and area
Pressure is force spread over an area. Enter both and get the result in every common unit.
- Pressure
Density, mass and volume
Density from mass and volume, in every common unit.
- Density
geography
Distance and bearing between two coordinates
Great-circle distance, initial bearing and midpoint between any two points on Earth.
- Distance between coordinates
- Bearing