How accurate is this finish time calculator?

This calculator gives you the exact time based on maintaining a constant pace throughout. In reality, most runners slow down over longer distances, so actual finish times may be slightly longer.

What pace do I need for a sub-4 marathon?

For a sub-4-hour marathon (42.195 km), you need to average faster than 5:41 min/km (9:09 min/mile).

What pace do I need for a sub-2 half marathon?

For a sub-2-hour half marathon (21.0975 km), you need to average faster than 5:41 min/km (9:09 min/mile).

Does elevation affect my finish time?

Yes, significant elevation gain will slow you down. A common rule of thumb is to add roughly 12-15 seconds per km for every 100m of elevation gain.

RunCalcs

Finish Time Calculator — Predict Your Race Time

Calculate your finish time for any distance based on your pace per kilometre.

Pace (minutes)

Pace (seconds)

Distance

How We Calculate This

Finish Time Formula

Finish time is calculated by multiplying your pace by the distance:

Finish Time = Pace (seconds/km) × Distance (km)

For example, at 5:30 min/km pace over a marathon (42.195 km): 330 × 42.195 = 13,884 seconds = 3:51:24.

Standard race distances: 5K = 5 km, 10K = 10 km, Half Marathon = 21.0975 km, Marathon = 42.195 km.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always consult a coach or medical professional for personalised training advice.