Hill effort converter

How this works

The conversion uses the energy-cost model from Minetti et al. (2002), the study behind most grade-adjusted pace features - runners were measured on gradients from -45% to +45% and the extra (or saved) energy per metre was fitted as a curve. This tool takes your hill pace, works out the energy you were spending, and finds the flat pace that costs the same.

Results are most reliable between about -20% and +20%, and the model assumes steady running - not hiking, and not technical trail where footing dominates.

Effort factors at a glance

Flat-equivalent pace = hill pace × factor. Below 1.0 means the hill was costing you extra (your flat-equivalent is faster than your watch showed).

Using it in training

• Judge hilly runs fairly. 5:30/km up a long 4% drag is a harder run than 5:10/km on the flat - GAP shows it.
• Pace hilly races by effort. Take your goal flat pace, and let the converter tell you what that effort looks like on each climb rather than fighting to hold one number.
• Respect steep descents. Beyond about -10% the cost rises again and the muscle damage bill arrives late in the race.
• Treadmill note: setting a treadmill to 1% is the old convention for mimicking outdoor flat running at quicker paces; this tool is for real gradients beyond that.

FAQs

What is grade adjusted pace?

The flat-ground pace that would cost the same energy as the pace you actually ran on the gradient. It's how Strava and training platforms make hilly runs comparable.

How much does 1% of gradient cost?

Roughly 3-4% more energy at the same speed - in practice around 10-15 seconds per kilometre at recreational paces. It compounds quickly: a 6% climb near-doubles that again.

Why doesn't downhill give back what uphill takes?

Physiology is asymmetric: descending returns only part of the energy, and steeper than about -10% your legs spend energy braking. A hilly loop is always slower than a flat one at equal effort.