A marathon is 26.219 miles (42.195 km), and the single number that determines whether you hit your goal is the pace you hold over every single mile. This marathon pace calculator takes your target finish time and turns it into a clean per-mile and per-kilometer pace, plus the split times you should be hitting at 5K, 10K, and the half-marathon mark on race day.
Whether you are chasing a sub-4-hour debut, trying to break 3 hours, or simply aiming to finish your first 26.2 miles upright, the math is the same: divide your goal time by the race distance and you have the rhythm you need to hold. Drop your target hours, minutes, and seconds below and watch the splits update instantly.
How to Use
- Enter your Target Hours — the hour portion of the finish time you want. A common first goal is 4 hours; a competitive age-group goal is 3 hours.
- Add your Target Minutes — for example, if you want to finish in 3:20, enter 20 here.
- Add your Target Seconds — optional, but useful if you are chasing a specific badge like sub-3:10:00.
- Set the Race Distance. The default is a full marathon at 26.219 miles. Change it to 13.109 for a half marathon, 6.214 for a 10K, or 3.107 for a 5K.
- Read the result card: your pace in minutes per mile and per kilometer, plus the exact 5K, 10K, and half-marathon splits you need to stay on track.
A 4-hour marathon requires an average of 9 minutes 9 seconds per mile (about 5:41 per kilometer). That is the rhythm you should lock into during the first few miles rather than chasing the fast starters around you.
The Pace Formula
Pace is just total time divided by distance. The engine converts your hours, minutes, and seconds into a single second count, then divides:
paceSecPerMile = (hours × 3600 + minutes × 60 + seconds) ÷ distanceMiles
To convert to kilometers, divide by 1.609344 — the exact conversion factor that defines a mile. Split times for the 5K (3.10686 mi), 10K (6.21371 mi), and half marathon (13.1094 mi) are then that same per-mile pace multiplied by the split distance. This assumes even pacing, which is the single biggest predictor of a strong marathon result.
Worked example: targeting a 4:00:00 finish means 14,400 seconds over 26.219 miles, or 549.2 seconds per mile — 9:09 per mile and 5:41 per km. At that pace you pass the half-marathon point almost exactly at 2:00:00, hit 10K in about 56:53, and pass 5K near 28:26.
Why Even Pacing Matters
Elite marathoners rarely negative-split by more than a few minutes, and age-group runners who start too fast often lose more than they gain. A 2023 analysis of New York City Marathon finishers found that runners who ran the first 10K more than 5% faster than their second 10K were three times more likely to slow down dramatically in the final 6 miles. The solution is simple: run the pace this calculator gives you from mile 1, even if the crowd is screaming and the guy next to you looks smooth.
Most training plans build a weekly long run that peaks at 18–22 miles. Use this tool to translate your goal pace into long-run effort: if marathon pace is 9:09/mile, your easy long-run pace should be 10:00–11:00/mile, and your tempo sessions should flirt with 8:15–8:30/mile. If you cannot hold those training bands comfortably in the final six weeks, adjust your goal finish time rather than risking a blowup on course.
Examples
Example 1 — A 4-hour marathoner. You want to break 4:00. Set hours = 4, minutes = 0, seconds = 0, distance = 26.219. The calculator returns 9:09 per mile and 5:41 per km, with a half split of 2:00:00. Tape this to your water bottle and run the first half dead on it; the second half will feel hard but survivable.
Example 2 — A half-marathon target. Training for a 1:30 half marathon? Set hours = 1, minutes = 30, seconds = 0, distance = 13.109. The pace works out to about 6:52 per mile (4:16 per km). Race entry fees for a major half marathon run $80–$200, so treat the pace plan as seriously as the registration cost.
Example 3 — A sub-3:05 attempt. Ambitious runners targeting 3:05:00 set hours = 3, minutes = 5, seconds = 0. That is 7:03 per mile (4:23 per km) for 26.219 miles. At that intensity you should already be logging weekly mileage above 50 miles, and your long-run fueling — roughly 30–60 grams of carbohydrates per hour, or about 2–3 energy gels — should be rehearsed in training, not invented on race morning.
FAQ
What pace do I need for a 4-hour marathon?
A 4-hour marathon requires an average of 9 minutes 9 seconds per mile, or 5 minutes 41 seconds per kilometer. That pace puts you at the halfway mark (13.1 miles) almost exactly at 2 hours 0 minutes, with a 10K split around 56:53 and a 5K split around 28:26.
What pace is a sub-3-hour marathon?
To break 3 hours you need to average 6 minutes 52 seconds per mile (4:17 per km). That is roughly the pace most recreational runners can hold for a 10K, which is why sub-3 is considered a serious barrier: it requires marathon-specific strength, consistent weekly mileage above 50–60 miles, and years of buildup.
How do I convert minutes per mile to minutes per kilometer?
Divide the per-mile pace by 1.609344. For example, 9:09 per mile becomes 5:41 per km. Most running watches display both units, but if yours only shows one, use this factor to cross-check.
What should my pace be for the first half vs the second half?
The safest plan is even pacing — the same per-mile pace for the entire race. Elite marathoners sometimes negative-split by 1–3 minutes, but age-group runners who start more than 5% faster than goal pace almost always blow up. Use the splits this calculator gives you and hit the half mark exactly on time.
How accurate is this calculator on a hilly course?
Flat-out this calculator assumes a flat course. Each 100 feet of climbing typically adds about 2–3 seconds per mile to your realistic pace, and a net downhill course (like Boston) can subtract a similar amount. If your race has more than 500 feet of elevation gain, add 5–10 minutes to your expected finish time.
What is a good marathon pace for a beginner?
Most first-time marathoners finish between 4:30 and 5:30, which is 10:18–12:35 per mile. If you can comfortably finish a half marathon at your goal marathon pace in training, you are in a realistic range. Do not try to race at a pace you have not already practiced on long runs.
Should I use miles or kilometers?
Use whichever unit your watch and race course display. USATF-certified US races list mile marks; World Athletics and most international races list kilometer marks. This calculator shows both so you can match whatever the course mile or kilometer signs tell you.
Disclaimer
This marathon pace calculator is provided for informational purposes only and does not constitute coaching, medical, or training advice. Pace figures are based on the simple average formula and assume flat terrain and even pacing; real performances vary with elevation, weather, wind, fueling, fitness, and race-day conditions. If you are new to distance running, managing a health condition, or increasing mileage significantly, consult a qualified coach or healthcare provider before beginning a training plan.