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RUNNERS LAB

Uphill Race
Predictor

Estimate a hilly finish from a flat race result and course elevation gain.

Last reviewed 25 August 2026

A 1:45 flat half with 250 m course gain predicts a slower hilly half. Enter a flat result, target distance, and gain. Get an estimated finish. Heuristic, not a GPS profile model.

Flat race time
KM
M

Net climb over the target distance.

Estimated hilly finish

1:51:55

  • 5:18 /KM
  • Avg grade 1.18%
  • ×1.066 vs flat
  • Estimate

What this result means

Uphill race prediction starts from a flat performance, optionally scales distance with Riegel when the target differs, then multiplies by a Minetti factor from average grade (gain ÷ distance).

Use elevation-adjusted finish when you already have a flat goal clock for the same distance. Use the ordinary race time predictor when the course is flat.

1:45 half, same distance, 250 m gain → finish slower than 1:45 by the average-grade multiplier.

A flat 20:00 5K toward a hilly 10K applies Riegel first, then the gain multiplier on the 10K distance.

Calculation method

Average grade % = (gain_m ÷ (distance_km × 1000)) × 100. Multiplier = Minetti cost(grade) ÷ cost(0). Finish = flat target time × multiplier. Flat target time uses Riegel when race and target distances differ.

Labeled estimate. Ignores downhills as relief, heat, and pacing strategy.

Net gain understates a course with big climbs and descents. This is not a segment-by-segment GAP integration.

Full methodology →

Frequently asked questions

How is this different from the race time predictor?

Riegel alone is flat. This page adds a climb multiplier from course gain after any distance scaling.

Should I use elevation-adjusted finish instead?

Use that page when you already have a flat goal time for the target distance. Use this page when you start from another flat race result.

Does it model downhills?

Only through net gain. A course that climbs 400 m and descends 400 m has 0 m net gain here and will not look hard in the multiplier.

Is this good enough for a mountain marathon?

Treat it as a rough planning number. Technical terrain and huge cumulative climb need more than average grade from net gain.

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