Deterministic reference tools
Tools for the things you need to work out
Choose a task, enter its inputs, and get a shareable result with the method and related facts. Every tool uses the same deterministic engines as the reference pages.
100 tools across 24 subjects. Search by task or subject, or browse the full set.
Embed up to three of 100 deterministic calculators on your own verified domain. Explore embeds →
100 of 100 tools
Music and audio
Tempo, beat length and delay timesEmbed
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
Music note frequency converterEmbed
Convert musical note names and MIDI numbers to equal-tempered frequencies.
Equal-tempered frequencies · MIDI note numbers
Chord inspectorEmbed
Inspect the notes, intervals and inversions represented by a chord symbol.
Chord symbol parsing · Chord notes and intervals · Inversions
Musical scale and mode explorerEmbed
List notes and intervals in a musical scale or mode.
Scale notes and intervals · Modes · Key signatures
Science and physics
Surface gravity and escape velocityEmbed
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 contractionEmbed
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
Speed, distance and timeEmbed
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 energyEmbed
Kinetic energy from mass and velocity, with the equivalents in everyday units.
Kinetic energy
Gravitational potential energyEmbed
Potential energy from mass and height at standard Earth gravity.
Potential energy
Wavelength and frequencyEmbed
Convert between the wavelength, frequency and photon energy of an electromagnetic wave.
Frequency/wavelength
Ideal gas lawEmbed
PV = nRT. Find the pressure of a given amount of gas at a given volume and temperature.
Ideal gas calculations
Radioactive decay and half-lifeEmbed
How much of a sample remains after a given time, given its half-life.
Half-life calculations
Pressure from force and areaEmbed
Pressure is force spread over an area. Enter both and get the result in every common unit.
Pressure
Density, mass and volumeEmbed
Density from mass and volume, in every common unit.
Density
Health and everyday calculations
BMI, body surface area and resting metabolic rateEmbed
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
Running pace, distance and timeEmbed
Work out pace per kilometre and per mile from a distance and a finish time, with equivalent times at the standard race distances.
Running pace · Pace per kilometre · Pace per mile · Race finish time
Finance and everyday maths
Compound interest and growthEmbed
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
Loan amortisationEmbed
Monthly payment, total interest and the balance over time for a repayment loan at a fixed rate.
Loan repayment · Monthly payment · Total interest · Amortisation schedule
Weather and everyday calculations
Dew point and humidityEmbed
Dew point, vapour pressure and absolute humidity from a temperature and relative humidity, using the Magnus formula.
Dew point · Relative humidity · Vapour pressure · Absolute humidity
Wind chillEmbed
The wind chill equivalent temperature from an air temperature and wind speed, using the 2001 North American formula.
Wind chill · Feels-like temperature · Apparent temperature
Heat indexEmbed
The heat index, or apparent temperature, from an air temperature and relative humidity, using the Rothfusz regression.
Heat index · Apparent temperature · Humidex · Feels-like temperature
Electronics and engineering
Gear ratioEmbed
Gear ratio from tooth counts, with the resulting change in speed, torque and direction of rotation.
Gear ratio · Mechanical advantage · Output speed · Torque multiplication
Ohm's law and electrical powerEmbed
Voltage, current, resistance and power. Enter any two, get the rest.
Ohm's law · Electrical power
Food and cooking
Baker's percentageEmbed
Scale a bread recipe by baker's percentage: hydration, salt and yeast as a share of the flour weight, and the total dough yield.
Baker's percentage · Dough hydration · Recipe scaling · Dough yield
Photography
Angle of viewEmbed
Horizontal, vertical and diagonal angle of view from a focal length and explicit sensor dimensions, with the field covered at a given distance.
Angle of view · Field of view · Focal length · Crop factor
Numbers and maths
Percentage changeEmbed
The change from one value to another, as a percentage, a multiplier and a difference.
Percentage change · Percentage increase/decrease
Greatest common divisor and lowest common multipleEmbed
GCD, LCM and the relationship between them for two integers.
GCD · LCM · Ratios
Logarithms, powers and rootsEmbed
Logarithms in any base, plus the matching power and root for the same pair of numbers.
Logarithms · Powers · Roots
Fraction simplifierEmbed
Simplify a fraction and inspect its equivalent forms.
Fraction simplification · Equivalent fractions
Ratio simplifierEmbed
Simplify a ratio and inspect its proportional form.
Ratios
Prime factorisation calculatorEmbed
Find the prime factorisation and divisor properties of an integer.
Prime factorisation · Number and sum of divisors
Roman numeral converterEmbed
Convert between Roman numerals and their integer values.
Roman numeral conversion
Integer properties explorerEmbed
Explore factors, divisibility, parity, primality and notable properties of an integer.
Factors · Divisibility · Prime and composite classification
Number name converterEmbed
Read an integer as an English cardinal and ordinal number.
English number name · Ordinal name
Fibonacci number inspectorEmbed
Check a number’s relationship to the Fibonacci sequence and nearby terms.
Fibonacci membership · Nearby sequence terms
Statistics and probability
Combinations and permutationsEmbed
How many ways to choose or arrange k items from n, with and without repetition.
Permutations · Combinations · Factorials
Probability of repeated eventsEmbed
Independent trials: at least one success, no successes, and expected counts.
Probability
Mean, median, mode and standard deviationEmbed
Summary statistics for a list of numbers, including quartiles and outliers.
Mean · Median · Mode · Range
Z-score and normal probabilityEmbed
Turn a value into a z-score given a mean and standard deviation, and read off its percentile and tail probabilities under a normal distribution.
Z-score · Standard score · Percentile rank · Tail probability
Confidence interval for a meanEmbed
Compute the confidence interval and margin of error for a sample mean, from the sample size, standard deviation and confidence level.
Confidence interval · Margin of error · Standard error · Critical value
Algebra and geometry
Chemistry
pH and hydrogen ion concentrationEmbed
Convert between pH, pOH and molar concentration at 25 °C.
Basic pH calculations
Molar mass and compositionEmbed
Enter a chemical formula to calculate molar mass and percentage composition.
Molar mass · Percentage composition · Compound names
Chemical equation balancerEmbed
Balance a chemical equation and see when the equation is impossible or has multiple solutions.
Equation balancing · Mass conservation · Underdetermined and unbalanceable equations
Geography
Distance and bearing between two coordinatesEmbed
Great-circle distance, initial bearing and midpoint between any two points on Earth.
Distance between coordinates · Bearing
Geographic coordinate inspectorEmbed
Inspect decimal latitude and longitude and convert them to degrees, minutes and seconds.
Coordinate formats · Location and time-zone facts
Developer tools
Cron expression explainerEmbed
Enter a cron expression to see what it means and inspect upcoming scheduled runs.
Cron field expansion · Cron in plain English · Next scheduled runs
UUID inspectorEmbed
Inspect a UUID’s version, variant and any timestamp information encoded in it.
UUID version and variant · UUID embedded timestamps
Semantic version inspectorEmbed
Inspect a semantic version and compare its precedence components.
Semver components · Precedence rules
ISBN validatorEmbed
Check an ISBN-10 or ISBN-13 and inspect its check digit.
ISBN check digits · ISBN conversion
EAN and UPC validatorEmbed
Validate retail product codes and calculate their check digit.
EAN-13 and UPC-A · GTIN check digits
Luhn check digit checkerEmbed
Validate a number using the Luhn checksum algorithm.
Luhn validation
IBAN validatorEmbed
Validate an IBAN structure and its mod-97 check.
IBAN mod-97 validation
ISSN validatorEmbed
Validate an ISSN and inspect its check character.
ISSN check digit
VIN inspectorEmbed
Check a vehicle identification number and inspect its encoded fields.
VIN check digit · VIN decomposition · Model year code
DOI inspectorEmbed
Inspect the structure of a Digital Object Identifier.
DOI structure
Regular expression explainerEmbed
Break a regular expression into its flags, groups, anchors and quantifiers.
Regex decomposition · Quantifiers · Character classes
MAC address inspectorEmbed
Inspect MAC address bytes, unicast/multicast status and local/global assignment bits.
MAC decomposition · Address bits · EUI-64 derivation
JWT header and claims inspectorEmbed
Decode a JSON Web Token header and payload without verifying its signature.
JWT header and claim decoding · Registered claim meanings
BCP 47 language tag inspectorEmbed
Parse and canonicalise a BCP 47 language tag.
BCP 47 decomposition · Canonical casing
Base64 text decoderEmbed
Decode supported Base64 text and inspect its character data.
Base64 decoding
Binary text decoderEmbed
Decode binary digits as bytes and text.
Binary to text decoding
Networking
IPv4 subnet calculatorEmbed
Inspect an IPv4 address and CIDR prefix to get its network, mask, broadcast and usable host range.
CIDR calculations · Subnet mask · Network address · Broadcast address
IPv6 address inspectorEmbed
Expand and classify an IPv6 address, including any embedded IPv4 address.
IPv6 compression · Address classification · Reverse DNS
IPv6 prefix inspectorEmbed
Calculate the range and size of an IPv6 prefix.
IPv6 prefix arithmetic · Address range
IP range classifierEmbed
Check whether an address belongs to a special-use, private, loopback or documentation range.
Special-use range classification
Dates and time
Unix timestamp converterEmbed
Convert a Unix timestamp to a readable UTC date and inspect its epoch forms.
Unix timestamps · Seconds and milliseconds · Unix epoch relationship
Date and calendar inspectorEmbed
Inspect a date’s weekday, ISO week, calendar formats and related facts.
Weekday · ISO week · Calendar conversions
Leap year and year inspectorEmbed
Check leap-year status and key day counts for a year.
Leap year · Days in year · Year relationships
Month calendar and working daysEmbed
Inspect a month calendar grid, weekday counts and working days.
Month calendar grid · Working days · Weekday counts
Easter Sunday calculatorEmbed
Calculate the date of Easter Sunday for a year.
Easter Sunday
Hebrew calendar converterEmbed
Convert a Gregorian date to its corresponding Hebrew calendar date.
Hebrew calendar conversion
Tabular Islamic calendar converterEmbed
Convert a Gregorian date to the tabular Islamic calendar.
Islamic calendar conversion
Persian calendar converterEmbed
Convert a Gregorian date to the arithmetic Persian calendar.
Persian calendar conversion
Measurements
Unit converterEmbed
Convert a measurement across supported units, with the conversion factor and method shown.
Measurement conversion · Exact conversion factors · Reverse conversion · Conversion formula
Colour and design
Colour converter and palette explorerEmbed
Explore a colour’s formats, contrast readings, harmonies and lighter or darker variants.
Colour format conversion · WCAG contrast checks · Colour harmonies · Palette variants
Web and identifiers
URL inspectorEmbed
Break a URL into its scheme, host, port, path, query and fragment.
URL structure · Query parameters · Path segments
Email address inspectorEmbed
Inspect the parts and basic format limits of an email address.
Email address parts · RFC length validation
HTTP status explainerEmbed
Look up an HTTP status code, its class and caching meaning.
HTTP status codes · Status class and cacheability
Port number lookupEmbed
Identify a common service and IANA range from a port number.
Well-known port numbers · IANA port ranges
MIME type lookupEmbed
Find a media type from a file extension or inspect a MIME type.
MIME media types · File extension mapping
International domain inspectorEmbed
Inspect internationalised domain names and their ASCII-compatible form.
Internationalised domain names · Punycode
Computing
Number base converterEmbed
Convert an integer between decimal, binary, octal, hexadecimal and other supported bases.
Decimal, binary, octal and hexadecimal · Base 32 and base 36
Unicode code point inspectorEmbed
Inspect a Unicode character, its code point and encoded byte forms.
ASCII characters · Unicode code points · UTF encodings
Two’s complement inspectorEmbed
Inspect signed binary representations using two’s complement.
Two’s complement · Bit length
Bitwise value inspectorEmbed
Inspect an integer’s binary form, bit length, population count and related representations.
Bit length · Population count · Bitwise operations
Byte order swapperEmbed
Inspect a value as bytes and compare byte-order representations.
Byte-order swap
Character code inspectorEmbed
Inspect a character’s ASCII or Unicode code point and text encodings.
ASCII characters · Unicode code points
Geometry
Circle area and circumference calculatorEmbed
Calculate a circle’s area and circumference from its radius or diameter.
Circle area · Circumference
Triangle calculatorEmbed
Inspect triangle measurements, area, perimeter and special relationships.
Triangle area · Triangle sides and angles
Regular polygon calculatorEmbed
Calculate a regular polygon’s angles, area and diagonal count.
Polygon angles · Area · Diagonal count
Sphere volume and surface areaEmbed
Calculate a sphere’s volume and surface area from its radius.
Sphere volume · Sphere surface area
Right triangle and Pythagorean checkerEmbed
Check whether side lengths form a right triangle and identify Pythagorean relationships.
Hypotenuse · Pythagorean triples
Text and writing
Text statistics and inspectorEmbed
Count words, characters, letters, digits and other features in a text sample.
Character and word counts · Text statistics
Text case converterEmbed
Inspect common case conversions including camel, snake and kebab case.
Uppercase and lowercase · camelCase · snake_case · kebab-case
Text encoding explorerEmbed
Inspect text as Unicode code points, UTF-8 bytes, Base64 and URL encoding.
Unicode code points · UTF-8 byte length · Base64 · URL encoding
Games and probability
Dice notation calculatorEmbed
Parse dice notation and calculate the mean, variance and outcome distribution.
Dice notation · Outcome counts · Mean and variance
Darts checkout finderEmbed
Find possible dart checkout routes for a score.
Dart checkout routes · Shortest finish
Science
Physical constant lookupEmbed
Look up a physical constant and distinguish exact defined values from measurements.
Physical constants · Exact versus measured values
Chemical element inspectorEmbed
Inspect an element’s symbol, atomic number, weight and electron configuration.
Chemical elements · Atomic weights · Electron configuration