Built for race organisers and clubs — a chronometer that runs right in your browser, with nothing to install. Open it once with a connection, then time the whole race fully offline — recording, rankings, pace and CSV export. Your results are saved on your device and won't be lost if you lose signal or close the app.
No app store, no sign-up — open it once online and it works offline (install it too, if you like).
Open the app to time a real race — every result stays on your device.
Enter a bib number and press Record (or Enter). Centisecond precision, even across midnight.
Filter results by overall, men, women and standard 10-year age categories with one tap.
Add a distance and Crono shows each runner's pace in min/km, in the table and the export.
Import a CSV (number, name, sex, birth year) to show names and power the categories.
Download full results — place, category place, name, sex, category, time and pace.
Open it once online, then time the whole race with no connection. Results are saved on your device and stay there between sessions — no account, no tracking.
Tap “Set start now” when the gun goes off, or type an exact start time.
Type each bib number and hit Record (or Enter) as runners cross the line.
Switch ranking tabs, add a distance for pace, then export everything to CSV.
Organising the event? Generate a range of numbered bibs with your event name, date and logo — pick a colour theme and download a clean, print-ready PDF (2 per A4 page). No timing needed; do it days before the race.
Generate bib numbersYou don't have to install anything — Crono runs in any browser straight from the web. But if you'd like a one-tap, full-screen launcher that also works offline, you can optionally install it as an app (it's a PWA), on mobile and desktop. No app store, no account.
Open Crono in Safari, tap the Share button (the square with an up-arrow), choose Add to Home Screen, then Add.
Open Crono in Chrome, tap the ⋮ menu, choose Install app (or Add to Home screen), then Install.
In Chrome or Edge, click the install icon in the address bar (or menu → Install Crono). It opens in its own window.
Tip: open Crono online once first so it can install and cache itself — after that it works with no connection.
Yes — it’s completely free and open-source. No account, no paywall.
Yes. Open Crono once while you have a connection (so it can load and install), then it keeps working completely offline — recording finishes, rankings, pace and exports all work with no signal. Great for start/finish lines with poor reception.
Yes — Crono installs on mobile too. On iPhone/iPad use Safari's Share → Add to Home Screen; on Android use Chrome's ⋮ menu → Install app; on desktop click the install icon in the address bar. See the install guide above. Once installed it launches full-screen and runs offline.
No — your start time, results and participants are saved on your device and stay there when you go offline, refresh or reopen the app. They're not sent anywhere. For extra safety (or to move to another device), use Backup to download a file you can Restore later. Clearing your browser's site data is the only thing that wipes them.
Times are recorded to the centisecond using your device clock. It’s great for club and in-house races, but for official, certified events keep a backup timing method.
Import a participant CSV with number, name, sex, birth_year. Crono derives standard 10-year athletics categories and lets you rank by them. You can also fill missing data inline.
Yes — one click downloads a CSV with place, category place, name, sex, category, time and pace.
Only in your browser (localStorage). Nothing is sent to a server; the operator can’t see or recover it, so export anything important.
Runs right in your browser — no account, no sign-up. Open it and start the clock.
Launch the timer