From parkrun debut to sub-15 — pick a target time, see your km splits and the 400 m lap paces that get you there. How accurate is this?
Your Goal Time
Hours
Minutes
Seconds
Units
Quick Goals
Who Runs This
Your 5K Pace
to finish a 5K in 20:00
Per Mile
6:26
Speed
15.00
km/h
400m Lap
1:36
| Distance | Split | Cumulative | Pace |
|---|---|---|---|
| 1 km | 4:00 | 4:00 | 4:00 |
| 2 km | 4:00 | 8:00 | 4:00 |
| 3 km | 4:00 | 12:00 | 4:00 |
| 4 km | 4:00 | 16:00 | 4:00 |
| FINISH · 5 km | 4:00 | 20:00 | 4:00 |
Most sub-20 5Ks aren't run even — they negative-split slightly after a controlled K1.
Why it works. Banking time only works if you have it to spend. K1 even pace + K5 surge nets the same 20:00 with less suffering.
5K Pace
4:00
min/km
5K Pace
6:26
min/mile
Equiv. 10K
41:42
Riegel predicted
Equiv. Half
1:32:00
Riegel predicted
To run 20:00 you need to hold 4:00/km (6:26/mi) from gun to tape. You'll hit the halfway point (2.5 km) in 10:00 and each 400 m lap should take 1:36. That pace projects a 41:42 10K via the Riegel formula.
Most fast 5Ks are run slightly negative — a controlled first kilometer followed by a progressive build. Going out too fast is the #1 mistake; lactate accumulates quickly and you'll blow up hard in km 3–4. Aim for K1 slightly above goal pace, K2–K4 locked in, and leave everything in K5.
At 4:00/km, each 400 m lap takes 1:36. For speed work, target 1:29/400 m (roughly 5-10 s per rep faster). For threshold cruise intervals, add 10-15 s per rep to goal lap pace.