Running Pace Calculator
Calculate running pace, finish time, or distance, and predict 5K, 10K, half and full marathon times. Supports km and miles. Works fully offline.
About this tool
A complete pace toolkit for runners. Enter any two of distance, time, and pace, and the tool computes the third instantly. Switch units between kilometers and miles, use quick presets for 5K, 10K, half and full marathon distances, and see your speed in km/h. The race predictions estimate your finish times across standard distances based on your current pace. Everything is calculated locally in your browser, so it works offline and nothing is sent anywhere.
Details
- Category
- Health & Fitness
- Version
- 1.0.0
- Size
- 23 KB
- Updated
- Jun 2026
Frequently Asked Questions
How do I calculate my pace?
Choose the "Pace" mode, then enter your distance and your finish time. The tool shows your pace per kilometer (or mile) and your average speed.
Can it predict my race times?
Yes. Once you enter your pace (or distance + time), the tool predicts finish times for 5K, 10K, half marathon, and full marathon assuming you hold a constant pace.
Does it support miles?
Yes. Toggle between km and mi at the top. Your distance value is converted automatically so it stays the same real distance, and pace/speed update to the chosen unit.
Are the predictions accurate for long races?
They assume a constant pace, which is a good estimate for shorter distances. For a marathon, most runners slow down over time, so treat the longer predictions as an optimistic target rather than a guarantee.