Explore
Convert, visualize, and simulate. Science for everyone.
Immersive journeys
Scroll-driven experiences that let you feel a unit — depth, height, speed, energy, size, time.
Community Unit Comparisons
Build a comparison, publish it, and see what everyone else has made.
Size & Height Comparison
Line up people, animals, buildings, vehicles and landmarks — drawn to true scale — and see exactly how they compare.
Money as Physical Cash
Enter a dollar amount and see what it actually looks like as real banknotes — the weight, the height of the stack, the length laid end to end, the area if tiled flat, the volume, and how long it would take to count.
Deep Sea Dive
Scroll down to dive — feel the depth, pressure, cold and darkness.
Altitude Climb
Scroll to climb — feel the altitude, the dropping pressure and the thinning air.
Speed Journey
Scroll to accelerate — feel the speed in km/h, Mach and the speed of light, and watch time dilate.
Asteroid Impact
Pick a size, material, speed and angle — and feel the energy in joules and megatons of TNT.
Size of Life
Scroll to grow bigger — feel the size of life, from a virus to a whale, all measured against you.
How Loud Is Loud?
Scroll to get louder — climb the decibel scale and feel why +10 dB means 10× the energy, not a little more.
How Much Radiation?
Scroll up the dose scale — from a banana to a lethal dose — and feel how big (and how small) a sievert really is.
pH Scale Visualizer
Drag the pH slider or tap a substance — and feel why each step on the pH scale is 10× the acidity.
Molarity Lab
Pick a solute, set the grams (or moles) and the volume — and watch molarity M = mol/L come alive as the colour deepens.
How Units Are Defined
Pick one of the 7 SI base units and meet the constant of nature that defines it — since 2019, even the kilogram is just Planck's constant.
The Scale of Data
Scroll to get bigger — climb from a single bit to all the world's data and feel how enormous a terabyte really is.
Who Was Alive?
Scroll through human history and watch famous lives light up — and discover who was alive at the same time.
You in Every Unit
Type your height, weight and age — and see yourself measured in heartbeats, nanoseconds, megatons and atoms.
Solar System to Scale
Scroll the real solar system at true distance — and feel how staggeringly empty space really is.
Deep Time
Scroll all 4.54 billion years of Earth at true scale — and feel how staggeringly recent life, and humans, really are.
World of Units
Pick a measurement convention and watch the planet split — then open any country's full Unit Passport.
World Live Counters
The world, right now — measured live in units. Watch population, CO₂, energy and data tick upward in real time, each figure backed by a cited source.