Free online running pace & speed converter - Distance/Time/Pace calculator with race presets
Pace is time per kilometer (min/km), speed is distance per hour (km/h). Pace 5:00/km = Speed 12 km/h. Lower pace = faster, higher speed = faster. Runners typically use pace as it directly reflects per-kilometer time.
Based on training pace: if 10K pace is 5:00/km, marathon pace is typically 15-30 sec/km slower, i.e. 5:15-5:30/km, finish time ~3:42-3:53. Also use Riegel formula: T2 = T1 ร (D2/D1)^1.06.
Negative split means running the second half faster than the first. For example, first half marathon in 1:50, second in 1:45. This is the recommended strategy for many elite runners to avoid starting too fast and crashing later.
Pace Calculator has no usage limits โ it's free and unlimited. Since processing is done client-side, speed depends on your device. For very large files, we recommend processing in batches for the best experience.
Absolutely. All processing happens locally in your browser. No data is sent to any server, so there's zero risk of data leaks. Your information stays completely under your control.
No. Pace Calculator uses client-side processing โ everything runs in your browser. Your data never leaves your device, and the tool works even without an internet connection.
Yes, Pace Calculator is completely free to use. No registration or login required โ all features are available immediately.
No. Pace Calculator is a web-based tool โ just open it in your browser and start using it. No downloads, plugins, or extensions required.
Yes. Pace Calculator is fully responsive and works on phones, tablets, and desktops. The interface adapts automatically to your screen size.