Health📅 18 March 2025⏱ 5 min read
How to Calculate Your Running Pace for 5K, 10K and Half Marathon
Pace, speed and finish time are all connected by simple maths. Here's how to calculate your target pace for any distance, predict race times, and structure your training zones.
JW
James WhitfieldPersonal Finance & Maths WriterJames has written about personal finance, health metrics, and everyday mathematics for over six years. He holds a BSc in Mathematics from the University of Leeds.
Whether you're training for your first 5K or trying to beat a personal best, understanding pace maths makes you a smarter runner. Here's everything you need to know to set realistic targets and structure your training.
The Core Formula
Pace = Time ÷ Distance
Time = Pace × Distance
Distance = Time ÷ Pace
Pace is usually expressed as minutes per kilometre (min/km) or minutes per mile (min/mi). Speed is the inverse — kilometres per hour or miles per hour.
Speed (km/h) = 60 ÷ Pace (min/km)
Pace (min/km) = 60 ÷ Speed (km/h)
Common Race Distance Reference Table
Pace (min/km)5K Finish10K FinishHalf Marathon
4:0020:0040:001:24:21
4:3022:3045:001:34:54
5:0025:0050:001:45:28
5:3027:3055:001:56:01
6:0030:001:00:002:06:35
6:3032:301:05:002:17:08
7:0035:001:10:002:27:41
Working Out a Target Finish Time Pace
If you have a goal time, divide by the distance to get the required pace.
Example: You want to finish a 10K in under 55 minutes.
Target pace = 55 minutes ÷ 10 km = 5:30 min/km
Now you know exactly what pace to hold in training runs to get comfortable at that effort level before race day.
Training Pace Zones
Most running coaches use 5 zones based on percentage of your maximum heart rate or of your 5K race pace. Here's how to estimate your zones from your current 5K pace:
ZonePurposePace vs 5K Pace
Zone 1 (Easy)Recovery, long runs+90–120 sec/km slower
Zone 2 (Aerobic)Base building, fat burning+60–90 sec/km slower
Zone 3 (Tempo)Lactate threshold work+20–40 sec/km slower
Zone 4 (Threshold)Race-pace running~5K pace
Zone 5 (Intervals)Speed, VO2 maxFaster than 5K pace
The most common training mistake is running Zone 2 runs too fast. Easy runs should feel genuinely easy — you should be able to hold a conversation. If you're breathing hard on a "recovery" run, you're working too hard and not getting the aerobic base benefit.
Predicting Race Times From a Known Performance
If you've run one distance recently, you can predict others using the Riegel formula:
T2 = T1 × (D2 ÷ D1)^1.06
T1 = Known time, D1 = Known distance
T2 = Predicted time, D2 = Target distance
Example: You ran 5K in 25:00. Predicting 10K:
T2 = 25 × (10 ÷ 5)^1.06 = 25 × 2^1.06 = 25 × 2.085 = 52:07
This formula accounts for the fact that longer distances require a slower average pace — you can't simply double your 5K time for a 10K. The 1.06 exponent captures this physiological reality.
The Effect of Terrain and Conditions
Flat road pace doesn't translate directly to trail or track. General rules of thumb:
- Treadmill to road: Add ~5–8 seconds/km to treadmill pace (roads have more variables)
- Wind: A headwind costs about twice as much time as a tailwind saves
- Altitude: Above 1,500m, pace slows by roughly 3–5% per 1,000m gained
- Heat: Running in 25°C vs 10°C slows pace by roughly 1–2% for most runners