JRP's Number Universe

A free universe for the number-curious. Pick a calculator and find out how big, how far, how fast, and how long — from ants to galaxies, from a single second to the age of the universe.

All-in-One Calculator

A premium workspace for arithmetic, science, algebra, graphing, formulas, finance, conversions, and engineering.

Crazy Date Calculator

The difference between any two dates — even billions of years apart, all the way back to the Big Bang.

Cosmic You — Timers

Seconds alive, heartbeats, Earth-spins, distance flown through space, and milestone countdowns.

Calendars Across Time

See one moment in the Gregorian, Julian, Islamic, and Maya calendars — plus how astronomers and computers count time.

How big is a billion, really? Every named number, written out in full — up to a googolplex.

Legendary Constants

π, e, φ, √2 and τ — the famous never-ending numbers, with a golden spiral and a 'find your birthday in pi' search.

Break numbers into primes, find GCD & LCM, test giant numbers for primality, and explore the Ulam spiral.

Speed & Distance

Light-travel times and how many footsteps it'd take to walk across the whole galaxy.

Turn any number into every unit at once — plus binary, hexadecimal, and Roman numerals.

You vs. a blue whale, a car vs. the speed of light — ratios across size, weight, and speed.

Weight in Space

What you'd weigh on every planet, moon, exoplanet — and near a black hole.

Type a message and scramble it with a dozen ciphers — Caesar, Morse, Vigenère, binary and more.

How Computers Count

Binary, octal & hex, an interactive byte builder, and how a computer stores your words.

Random Universe

Roll random numbers, dice, and coins — with facts about every result and a live fairness histogram.

Probability & Odds

Play the Birthday Paradox and Monty Hall, watch dice-sum bell curves, and translate odds into real-world rarity.