Half Marathon Time & Pace Calculator
Use this 13.1 mile (21.1 km) calculator to estimate your finish time from pace, or find your average pace from a goal finish time.
1) Finish Time from Pace
Enter your average pace and select your pace unit.
2) Pace from Goal Time
Enter your target half marathon finish time.
Why Use a Half Marathon Time Calculator?
A half marathon time calculator helps you translate effort into outcomes. If you know your pace, you can estimate your finish time. If you know your goal finish time, you can determine the pace you need to hold over 13.1 miles (21.0975 km). This is useful for training plans, race strategy, and realistic goal setting.
Runners often train hard but race without a clear pace plan. A quick half marathon pace calculator removes guesswork and gives you concrete numbers to follow on race day.
How to Use This Calculator
Option A: Pace to Finish Time
- Enter your average pace minutes and seconds.
- Select whether the pace is per mile or per kilometer.
- Click Calculate Finish Time to get your projected time.
Option B: Goal Time to Pace
- Enter your target half marathon time in hours, minutes, and seconds.
- Click Calculate Pace to see required pace per mile and per km.
- Use the generated checkpoint splits to keep your race effort steady.
Common Half Marathon Goal Times and Equivalent Paces
| Goal Time | Pace per Mile | Pace per Kilometer |
|---|---|---|
| 1:30:00 | 6:52 /mi | 4:16 /km |
| 1:40:00 | 7:38 /mi | 4:44 /km |
| 1:45:00 | 8:00 /mi | 4:58 /km |
| 1:50:00 | 8:23 /mi | 5:12 /km |
| 2:00:00 | 9:09 /mi | 5:41 /km |
| 2:15:00 | 10:18 /mi | 6:24 /km |
Practical Pacing Strategy for 13.1 Miles
1. Start Controlled
The first 2-3 miles should feel easy. Adrenaline can make you start too fast, which often leads to a difficult final 5K.
2. Lock Into Goal Pace
From mile 3 to mile 10, focus on rhythm and efficiency. Keep your breathing controlled and check splits every mile or every 5 km.
3. Finish Strong
If you paced well, miles 10 to 13.1 are where you can pass people and gain confidence. A slight negative split (faster second half) is often ideal.
Training Tips to Improve Half Marathon Time
- Long run: Build endurance with weekly long runs, gradually increasing distance.
- Tempo runs: Improve lactate threshold by running sustained efforts near half marathon pace.
- Intervals: Add speed economy with VO2-focused repeats (e.g., 800m or 1 km reps).
- Easy miles: Most runs should be easy to support recovery and consistency.
- Taper week: Reduce volume before race day to arrive fresh.
Frequently Asked Questions
What is a good half marathon time?
It depends on your running background. For many recreational runners, finishing under 2:00 is a common milestone. For experienced runners, 1:30-1:45 can be a strong target.
Is half marathon pace the same as 10K pace?
No. Half marathon pace is usually slower than 10K pace, but faster than marathon pace. Your exact ranges depend on your fitness and race experience.
Should I pace by mile or kilometer?
Either works. Use whichever aligns with your watch settings and race markers. This calculator supports both pace formats so you can train and race confidently.
Final Thought
A half marathon time calculator is simple, but powerful. Use it to set realistic goals, train with intention, and execute a smart race strategy. Consistent pacing is often the difference between surviving 13.1 miles and running your best race.