Calculate pace, time, or distance for any run. Works for 5K, 10K, half marathon, marathon, and any custom distance.
Pace = Total Time ÷ Distance. For example, if you run 5K in 25 minutes, your pace is 25 ÷ 5 = 5:00 per km, or 25 ÷ 3.10686 ≈ 8:03 per mile. This calculator handles all the conversions automatically.
Negative splits means running the second half of a race faster than the first half. It's the most effective race strategy for most distances, helping you conserve energy early and finish strong. Most world records are set with negative or even splits.
A rough formula: multiply your 5K time by 9 to estimate your marathon time. For example, a 25-minute 5K suggests a ~3:45 marathon. However, this assumes strong marathon-specific training (long runs, tempo runs). Use the pace found above to plan your marathon splits.
This running pace calculator solves the three core questions every runner faces: What pace do I need? (enter distance + goal time), How long will it take? (enter distance + pace), and How far did I run? (enter time + pace). It works for any distance — 5K, 10K, half marathon, marathon, or a custom run — in both miles and kilometers.
Unlike distance-specific tools, this calculator is built for everyday training decisions: figuring out your easy run pace, planning long-run targets, converting a training plan from one unit system to another, or verifying your Garmin watch data. Just switch modes with the tabs and enter what you know.
Tip: Use the preset buttons (5K, 10K, Half, Marathon, 1 Mile) to instantly populate the distance field. Then enter your time or pace and the result appears immediately. All calculations update in real time as you type.
You know your goal distance and target finish time. Get the exact pace per mile and km to maintain throughout. Ideal for race planning.
You know your comfortable pace and a race distance. Calculate your predicted finish time. Great for deciding if a race goal is realistic.
You ran for a set time at a known pace. See how far you went in km and miles. Useful when running by time rather than a measured route.
In 2026, the most common pacing mistake is still trusting your watch’s instant pace on tree-lined routes, city streets, or sharp turns. It often lags by 5–15 seconds per mile, which can make you surge too hard early. For a 5K, pace by lap pace instead: set auto-lap to 1 km or 1 mile and judge effort from the average split, not the live number bouncing on your wrist. If your watch supports dual-band GPS, turn it on before race day and test battery drain first.