From the imperceptible creep of a tectonic plate to the blinding flash of light itself — explore the full scale of speed in the universe.
Speed is one of the few physical quantities that touches everything — biology, geology, astronomy, engineering, sport, weather, even the foundational physics of light itself. And yet, most of us think about it in just a narrow band: how fast a car goes, how quickly we can walk, perhaps how fast a plane flies. We rarely stop to consider the staggering range of speeds that exist in the universe, from the imperceptible drift of continents to particles arriving at almost the exact velocity of light.
How Fast Is is a project built to make that full range tangible. Inspired by the brilliant Scale of the Universe visualisations of size, this site does the same for velocity — placing more than 400 real-world examples on a single logarithmic scale, from the slowest measurable phenomena to the absolute speed limit of the cosmos.
A linear scale wouldn't work here. If we placed everything from a glacier's flow (a few centimetres per year) to the speed of light (300 million metres per second) on the same straight axis, almost everything would crush together at the slow end, and the entire visible universe of fast things would be invisible at the top. The numbers span more than twenty orders of magnitude — meaning the fastest things are roughly a hundred billion billion times faster than the slowest.
A logarithmic scale spreads these out by powers of ten, so a snail (about 0.013 m/s), a sprinter (about 10 m/s), and a bullet (about 1,000 m/s) all sit at visible intervals from one another. It's the only sensible way to look at the full range at once.
The dataset spans nine categories, chosen to give a broad sense of how speed plays out across very different domains:
The main explorer is a vertical scale you can scroll, tap, or swipe through. Each item shows the speed in your preferred unit (m/s, km/h, or mph — toggle the unit button to switch), a short description, an interesting fact, and comparisons to other items on the scale. The vertical ruler on the left lets you scrub quickly through many items at once.
Every item has its own URL: visit /explorer.html?id=cheetah to land directly on the Cheetah card, share that link, or bookmark it for later. The deep linking means search engines can index each item individually, and any specific comparison you find interesting is easy to share.
Building this dataset surfaced a number of facts that were genuinely surprising even after researching them:
Every figure on the site has been sourced from published references — Wikipedia, NASA, peer-reviewed journals, and established sports records. Where a speed varies (a cheetah's top speed depends on the individual; a tornado's wind speed depends on the storm category), we've used either a typical value or a well-cited peak, and made the distinction clear in the description.
Items are typically described to about 200-300 characters, with an additional "key fact" highlighting something not covered in the main description. We've worked hard to make those facts genuinely interesting — historical, biological, mechanical, surprising — rather than just restating numbers.
The dataset is updated periodically. If you spot an error or have a suggestion for an item we've missed, contact us at hello@how-fast-is.com.
This website was built using Claude AI. AI can — and sometimes does — get things wrong. The speed values and descriptions have been cross-referenced with established sources, but if something looks off, please double-check before quoting it. We welcome corrections at the address above.
If you've never explored the scale before, three good places to start:
From any of these, you can scroll up or down through the scale, or use the search button to jump to any specific item. The explorer remembers where you've been, so you can bookmark or share any URL.
For deeper reading, we publish in-depth articles on speed-related topics. Some places to start:
See the full articles index.
Light, in a vacuum, at 299,792,458 metres per second. Nothing with mass can reach this speed. Photons (particles of light), gravitational waves, and other massless phenomena all travel at exactly this velocity. Many things travel near the speed of light — cosmic ray particles can reach 99.99999% of it — but only massless things ever reach it.
Currently, the slowest item is plastic degradation, at around 10⁻¹² metres per second — a thousand-billionth of a metre each second. Continental drift is also remarkably slow at roughly 10⁻⁹ m/s (a few centimetres per year). Glaciers flow at the equivalent of around 1 metre per day, faster than you might expect.
Earth's surface at the equator rotates at 465 m/s. The entire planet orbits the Sun at 29,800 m/s (about 107,000 km/h). The Sun, dragging Earth along, orbits the centre of the Milky Way at roughly 230,000 m/s. And the Milky Way itself moves toward the Great Attractor at about 600,000 m/s. So your "stationary" position is, depending on how you count, doing something remarkable already.
According to Einstein's special relativity, anything with mass would require infinite energy to reach the speed of light. The closer a massive object gets to that speed, the more energy it requires to accelerate further — energy scales with a factor that becomes infinite at the speed limit. Massless particles like photons aren't bound by this and travel at light speed by default.
Where a single canonical value exists (the speed of light, the speed of sound in dry air at 20°C, Usain Bolt's measured 100m peak velocity), the figures are exact. For animals, vehicles, and natural phenomena, we use either a typical figure or a well-documented record, and the description text makes clear which is which. If you're using these figures for scientific work, please check the linked Wikipedia source for the latest research.