Pace Calculator
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Calculate your running pace, speed, or finish time. Works for 5K, 10K, half marathon, marathon or any custom distance.
Quick answer: Pace (min/km) = time ÷ distance. Speed (km/h) = 60 ÷ pace (min/km) — a 6:00/km pace equals 10 km/h. A sub-2-hour half marathon requires averaging 5:41/km (9:09/mile).
Pace
5:30 /km
📐 Formula
Pace (min/km) = Time (seconds) ÷ Distance (km) ÷ 60. Speed (km/h) = 3600 ÷ Pace (sec/km). Finish Time = Pace × Distance
How to Use the Pace Calculator
Choose your calculation type
Select whether you want to calculate pace from distance and time, finish time from distance and pace, or distance from time and pace.
Enter your values
Input distance in km or miles and time in hours, minutes, and seconds. For finish time calculation, enter your target pace per km or per mile.
Select your target race distance
Use the race time estimator to see projected finish times across standard distances (5K, 10K, half marathon, marathon) based on your current pace.
Use splits for training
The split calculator shows your required pace per km or per mile for a target finish time — essential for pacing strategy in long races.
Understanding Running Pace
Running pace (time per distance unit) and speed (distance per time unit) are inverses of each other. To convert: Speed (km/h) = 60 ÷ Pace (min/km). A 6:00/km pace equals 10 km/h. A 5:00/km pace equals 12 km/h. Most runners think in pace because it directly maps to effort — you run to a target time per kilometre rather than a speed readout, which is why GPS watches display pace by default.
Pace Benchmarks for Common Race Distances
5K: Beginner 8–9 min/km (40–45 min finish); Intermediate 5:30–6:30/km (27–32 min); Advanced under 4:30/km (under 22 min). 10K: Beginner 8–9 min/km (80–90 min); Intermediate 5:30–6:30/km (55–65 min); Advanced under 4:30/km (under 45 min). Half Marathon (21.1km): Sub-2 hours requires 5:41/km average. Marathon (42.2km): Sub-4 hours requires 5:41/km; sub-3:30 requires 4:58/km; sub-3 hours requires 4:15/km.
The 10% Rule: Avoiding Overtraining Injuries
The most widely cited guideline in running injury prevention is the 10% rule: do not increase weekly mileage by more than 10% from one week to the next. Running injuries (shin splints, stress fractures, IT band syndrome, plantar fasciitis) are predominantly overuse injuries caused by increasing volume or intensity faster than connective tissue can adapt. Muscles adapt faster than tendons and bones — feeling capable of running more does not mean your tendons are ready. A conservative build phase with scheduled easy recovery weeks every 3–4 weeks dramatically reduces injury risk for runners at all levels.
Easy vs Hard Runs: The 80/20 Principle
Research on elite distance runners consistently shows approximately 80% of training volume at easy pace (conversational, below lactate threshold) and 20% at hard effort. For most amateur runners, the inverse is true — almost all runs feel moderate-to-hard. Easy runs should be slower than you think: for a runner whose 5K pace is 5:30/km, easy pace is typically 7:00–8:00/km. Running too hard on easy days impairs recovery, reduces training quality on hard days, and increases injury risk. Use pace targets from this calculator to set zone boundaries for each training run.
How to Calculate Running Pace by Hand: Worked Example
A runner completes 5 km in 25:00. Pace = time ÷ distance: 25 minutes ÷ 5 km = 5:00 per km, or converting to miles (1 km = 0.62137 miles): 5:00 ÷ 0.62137 ≈ 8:03 per mile.
How do you predict a race time at a different distance from this pace?
Pace doesn't scale linearly across distances — endurance, not just pace, becomes the limiting factor over longer races. The widely used Riegel formula predicts this: T₂ = T₁ × (D₂ ÷ D₁)^1.06, where the exponent 1.06 (rather than 1.0) captures the expected slowdown at longer distances. Using the 25-minute 5K as the known result to predict a marathon (42.195 km): T₂ = 1,500 seconds × (42.195 ÷ 5)^1.06 = 1,500 × 8.439^1.06 ≈ 14,400 seconds, or almost exactly 4 hours — noticeably slower per-kilometer than the 5K pace, reflecting the reality that maintaining 5K intensity for 42 km is not physiologically sustainable for almost any runner.
How Should Training Pace Differ From Race Pace?
What is the 80/20 principle in run training?
Many endurance coaches recommend roughly 80% of weekly training volume at an easy, conversational pace and only 20% at hard, race-specific intensity. Training too much at a hard pace paradoxically tends to produce worse race results and higher injury risk than a training plan dominated by genuinely easy running, since the body needs the lower-intensity volume to build aerobic base without accumulating excess fatigue.
What is the 10% rule for increasing training volume?
To reduce overuse injury risk, weekly mileage is commonly capped at no more than a 10% increase over the previous week's total. A runner covering 20 miles one week would cap the following week at 22 miles under this guideline — a conservative pace of progression that still compounds meaningfully over a training block (roughly doubling volume in about 7–8 weeks) without the abrupt jumps most associated with stress fractures and tendon injuries.
Why does the same pace feel different on different days?
Heat, humidity, elevation gain, terrain, and accumulated training fatigue all shift the effort required to hold a given pace — a "5:00/km effort" on a hot, hilly day can represent meaningfully harder physiological work than the identical pace on a cool, flat day. Many runners find tracking effort (perceived exertion or heart rate) alongside pace gives a more consistent training signal than pace numbers alone, especially across varying conditions.
Frequently Asked Questions
A comfortable beginner pace is 8–10 minutes per km (13–16 min/mile). For a 5K, that's 40–50 minutes. Focus on finishing without stopping before worrying about pace.
You need to average 5:41 per km (9:09 per mile) to finish a half marathon (21.1 km) in exactly 2 hours. Aim for 5:35/km in training to have a buffer.
Speed (km/h) = 60 ÷ pace (min/km). For example, a 6:00/km pace = 10 km/h. A 5:00/km pace = 12 km/h.
Increase weekly mileage by no more than about 10% from one week to the next. Running injuries are predominantly caused by increasing volume or intensity faster than tendons and bones can adapt, even when muscles feel ready for more.
Research on distance runners generally supports around 80% of weekly volume at an easy, conversational pace and 20% at hard, race-specific effort — most amateur runners do the opposite, running too many moderate-to-hard days that impair recovery.
Sources & Methodology
Calculations are based on the most current publicly available data from authoritative government and industry sources: