How do I calculate my marathon pace from a half marathon time?

Multiply your half marathon time by 2.1–2.15 for a realistic marathon prediction. For example, a 1:45 half marathon predicts roughly 3:40–3:46 for the full marathon. The Riegel formula (time × 2.0946) gives the mathematical prediction, but most recreational runners should add 5–10 minutes to account for fatigue after mile 20.

How do marathon pace charts work?

A marathon pace chart shows the cumulative time you should hit at each kilometer or mile split for your target finish time. For example, a 3:30 marathon pace chart shows you should pass 10 km at 49:47, the half marathon at 1:45:00, 30 km at 1:29:33, and 40 km at 1:59:24. Use it during the race to check if you are on target.

How does temperature affect marathon pace?

Each 5°C rise above 10–12°C (50–55°F) slows marathon pace by roughly 1–3% for recreational runners. At 25°C, expect to add 5–15 minutes to your finish time. At 30°C+, add 15–30 minutes. Race-day heat is the single biggest external factor that invalidates pace calculator predictions.

Marathon Pace Calculator

Calculate your marathon pace, get a full split chart per km and mile, and predict race times from 5K to marathon — free, no signup.

Enter your target marathon finish time to get pace per km and per mile, or enter a recent race result (5K, 10K, half marathon) to predict your marathon time using the Riegel formula. The split chart shows cumulative time at every kilometer.

Enter your goal marathon finish time to get pace and split chart.

Hours Minutes Seconds

What is a marathon pace calculator?

A marathon pace calculator converts your target finish time into a pace per kilometer or mile and generates a split chart showing where you should be at every kilometer of the race. It answers the simplest and most important marathon question: "how fast do I need to run each km to finish in my goal time?"

How marathon pace is calculated

Marathon pace = total finish time ÷ 42.195 km. For a 3:30 marathon:

210 minutes ÷ 42.195 km = 4:58 min/km

210 minutes ÷ 26.219 miles = 8:01 min/mile

The split chart multiplies pace × distance at each km checkpoint so you know your cumulative target time at every point in the race.

Race time prediction: the Riegel formula

To predict marathon time from a shorter race, this calculator uses the Riegel formula — the most widely cited race prediction model:

T₂ = T₁ × (D₂ / D₁)^1.06

Where T₁ is your known race time, D₁ is that race distance, D₂ is the target distance, and 1.06 is the fatigue exponent. This formula works best when predicting within 2× the known distance. For marathon predictions from a 5K, it tends to be 5–15 minutes too optimistic for recreational runners — add a buffer.

Marathon pace chart: common finish times

Quick reference for popular marathon targets:

Finish time	Pace (min/km)	Pace (min/mile)	Half split	Level
2:30	3:33	5:43	1:15:00	Elite
3:00	4:16	6:52	1:30:00	Advanced
3:30	4:58	8:01	1:45:00	Strong recreational
4:00	5:41	9:09	2:00:00	Solid recreational
4:30	6:24	10:18	2:15:00	Average
5:00	7:07	11:27	2:30:00	Beginner
5:30	7:49	12:36	2:45:00	First-timer
6:00	8:32	13:44	3:00:00	Walk/run

How to use the marathon pace chart on race day

Print or screenshot the split chart from the calculator above. At each km marker, check your watch against the chart:

On target: your time matches the chart within ±15 seconds — keep going.
Ahead of pace: you are faster than the chart. Intentional? Great. Accidental? Slow down before mile 20 catches up.
Behind pace: do not panic-sprint. Recalculate a new realistic target and settle into that pace.
The wall (km 30–35): if pace drops here, it is glycogen depletion. Take a gel, focus on form, and accept 10–20 seconds slower per km until the finish.

Negative splits: the smart pacing strategy

Running the second half of the marathon faster than the first is called negative splitting. Research shows that runners with a second half slower by more than 8% significantly underperform their predicted time, while those within 4% overperform. Start 10–15 sec/km slower than target for the first 10 km, then gradually settle into goal pace.

Factors that affect marathon pace

Factor	Impact on finish time	What to do
Temperature >20°C (68°F)	+5–20 min	Slow pace 10–20 sec/km, hydrate every 5 km
Hilly course	+3–15 min	Add ~12 sec/km per 100m elevation gain
Wind >20 km/h headwind	+3–8 min	Draft behind other runners, adjust expectations
Altitude >1,500m	+5–15 min	Acclimate 2+ weeks or add time buffer
First marathon	+10–20 min vs prediction	Use prediction as A goal, add 15 min for B goal
Under-trained (<50 km/week)	+10–30 min vs prediction	Add 1–2 min/mile to predicted pace

Marathon nutrition and pacing

Pace and nutrition are inseparable in the marathon. Your body stores about 2,000 kcal of glycogen — a marathon at 4:00 pace burns ~2,600–3,200 kcal. Without mid-race fueling, you hit "the wall."

Before: eat a carb-heavy meal 2–3 hours before the start (600–800 kcal).
During: take 30–60g carbs per hour from gels, chews, or sports drink — start at km 8, not km 25.
Hydration: 400–800 ml per hour depending on heat. Do not overdrink — hyponatremia is a real risk.
After: 20–30g protein + carbs within 30 minutes for recovery. A runner's meal plan helps structure race-week nutrition.

Training paces from your marathon goal

Once you know your marathon pace, use these percentages to set training intensities:

Workout	% of marathon pace	Example (4:00 marathon)
Easy / recovery runs	75–80%	7:00–7:30 min/km
Long runs	80–90%	6:20–7:00 min/km
Marathon pace runs	100%	5:41 min/km
Tempo / threshold	108–115%	4:57–5:16 min/km
Interval / VO2max	120–130%	4:22–4:44 min/km

Marathon world records

Category	Time	Pace (min/km)	Runner
Men	2:00:35	2:51	Kelvin Kiptum (2023)
Women	2:09:56	3:05	Ruth Chepngetich (2024)

Bottom line

Marathon pace = finish time ÷ 42.195 km
Use the split chart at every km marker to stay on target
Start 10–15 sec/km slower, negative-split the second half
Race predictions from short distances are optimistic — add a buffer
Heat, hills, and under-training add 5–30 minutes to any prediction
Fuel with 30–60g carbs/hour starting at km 8

Next: calculate calories burned running, check your heart rate zones, or get a 7-day runner's meal plan.

Frequently asked questions

What pace do I need to run a 4-hour marathon?+

5:41 min/km or 9:09 min/mile. That is roughly 5 minutes and 41 seconds for each of the 42 kilometers. Most runners aiming for sub-4 do tempo runs at 5:20–5:30 and long runs at 6:00–6:30.

What is a good marathon pace for beginners?+

First-time marathoners typically finish in 4:30–5:30 (pace 6:24–7:49 min/km). Focus on finishing comfortably rather than chasing a time goal. Run long runs at conversational pace and add 30–60 sec/km as a race-day buffer.

How do I predict my marathon time from a half marathon?+

Multiply your half marathon time by 2.1–2.15. A 1:45 half predicts roughly 3:40–3:46 for a full marathon. The Riegel formula gives time × 2.0946, but add 5–10 minutes for the fatigue of miles 20–26.

What is the average marathon finish time?+

About 4:21 for men and 4:48 for women globally. In major marathons (Boston, London, Berlin), averages are 3:50–4:10 (men) and 4:15–4:40 (women). Only about 20% of runners finish under 4 hours.

What pace is a 3-hour marathon?+

4:16 min/km or 6:52 min/mile. Only about 5% of marathon runners break 3 hours. It requires VO2max above 55 ml/kg/min, 80–100+ km weekly training, and years of experience.

Should I run negative splits in a marathon?+

Yes. Start 10–15 sec/km slower than target for the first 10 km, settle into goal pace by km 15, and run the last 10 km at or slightly below goal pace. Positive splits greater than 8% are strongly correlated with worse finish times.

How does heat affect marathon time?+

Each 5°C above 10–12°C slows pace by 1–3%. At 25°C, add 5–15 minutes. At 30°C+, add 15–30 minutes. Heat is the biggest external factor that makes pace predictions inaccurate. Slow down early — your finish time will thank you.

How many calories does a marathon burn?+

A marathon burns 2,200–3,500 kcal depending on body weight. A 70 kg runner burns about 2,600 kcal. You need to fuel during the race (30–60g carbs/hour) because glycogen stores only hold ~2,000 kcal. Use our running calorie calculator for an exact estimate.

Key takeaways

Marathon pace = finish time ÷ 42.195 km (or ÷ 26.219 miles)
Use the split chart to stay on target at every km marker during the race
Riegel formula predicts race times but is 5–15 min optimistic for first-timers
Negative splits (second half faster) outperform positive splits consistently
Heat, hills, altitude, and training volume all add minutes to predictions
Fuel during the race: 30–60g carbs/hour from km 8 onward

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