Type in your marathon goal time and this calculator returns your required per-kilometre pace, per-mile pace, and every 5K checkpoint split to the second. It also shows the easy and threshold training paces you should be hitting in practice to get there. No sign-up, no ads, instant.
| Distance | Split time | Cumulative |
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Most runners chase a finish time — sub-3, sub-4, sub-3:30 — but the finish time is just the output. The input is pace consistency across all 42.195 kilometres. A runner who goes out at 4:10/km aiming for 2:55 and fades to 4:45 in the final 10km finishes in roughly 3:04. The same runner who locks in 4:08/km from the gun and holds it crosses in 2:54. The gap is entirely pacing discipline, not fitness.
This calculator gives you the exact pace you need to hold, so you can set your GPS watch alert to beep when you deviate, programme your Garmin structured workout with the target band, and rehearse that pace in training before race day.
The 5K split table above is the full breakdown, but there are four checkpoints that actually tell you whether you're on course:
Write these four splits on your arm with a marker. You want the number before the race, not on your phone at mile 18.
Marathon pace is not the same as threshold pace and it is not easy pace. It sits between the two — a demanding aerobic effort you can sustain for 3-5 hours if your aerobic base is built correctly. Understanding the relationship between these zones is what the training pace output above is trying to show you.
Going out too fast is the single most common marathon error, but it is not the only one. Here are the pacing mistakes that cost runners at least 5 minutes per race — often more:
Knowing your required pace is the start. Building the fitness to hold it for 42 kilometres requires 16-20 weeks of structured work. A typical build for a sub-3:30 marathon (4:58/km) looks like this: an 8-week base phase of mostly easy running with weekly mileage building to 60-70 km per week; a 6-week build phase introducing marathon-pace segments of 10-20 km within long runs and two threshold sessions per week; a 4-week peak phase where the longest run reaches 34-36 km and the weekly mileage tops out; then a 2-3 week taper reducing volume while keeping intensity.
Get-Split generates this structure automatically from your goal time and VDOT, pushes each session to your Garmin watch as a structured workout with pace bands, and adjusts mid-cycle if a time trial shows your fitness has shifted.
Build my marathon plan →Sub-3:00 requires an average pace of 4:16 per kilometre or 6:52 per mile across the full 42.195 km. Your 10K checkpoint should land at 42:40, your half marathon at 1:29:55. Any significant deviation before 30K usually ends in a slower finish, not a faster one.
Sub-4:00 requires 5:41 per kilometre or 9:09 per mile. Your half should go through at 2:00:00 or just under. At this pace, your training easy runs should be around 6:30/km, and your threshold work around 5:28/km.
Over a full marathon, 10 seconds per kilometre faster or slower equals roughly 7 minutes on the finish time. Starting at 4:15/km instead of 4:25/km means arriving 7 minutes earlier — but only if you can hold it. A 10-second-per-km fade in the final 12 km costs around 2 extra minutes.
Use whichever the course uses. Most European marathons mark in kilometres; US marathons mark in miles. Set your watch to match the course markers so you can verify your splits at each checkpoint without mental arithmetic during the race.
Run your target marathon pace on a flat road on a cool day and note the heart rate after 20 minutes of steady running. That is your marathon-effort heart rate. On race day, keep HR within 5 beats of that number for the first 30 km, then race by feel. Pace and HR together give you two independent checks.
The data says yes: the majority of world marathon records and age-group records are run with a roughly even or slightly negative second half. A 1-2 minute negative split is realistic and beneficial. A 5-10 minute negative split usually means you jogged the first half and left time on the course. Aim for even.