Rainy day treadmill equivalent

Set the treadmill to match your usual outdoor run.

Your details

Outdoor pace 9:00 a mile

10.7 km/h

at 1.0% incline (6.7 mph)

Distance in 30 minutes3.3 miles (5.4 km)
Incline for the flat1% (Jones and Doust, 10.5 to 18 km/h)

The incline makes up for the missing air resistance outdoors. Treadmills vary in calibration, so go by effort as well as numbers, and hold the rails only to get on and off.

The working

9 minute miles

9:00 a mile is 10.7 km/h (6.7 mph). Set 1% incline. In 30 minutes you will cover 3.3 miles.

If your usual 30 minute route climbs 60 m, that is 60 m over 5.4 km, an average of 1.1%, so set about 2.1%. A treadmill cannot give back the downhills, so this is a rough match: go by effort too.

Why 1%

Jones and Doust 1996

Outdoors you push through air. Jones and Doust found a 1% incline matches the energy cost of flat outdoor running between 10.5 and 18 km/h (2.92 to 5.0 metres a second). Below about 10.5 km/h air resistance is small, so 0 to 1% is fine; we use 0.5%.

Treadmill tips

Comfort

Have a fan on
Treadmills differ, so judge by effort as well
Look ahead, not down
Use the safety clip

Read with care

What this cannot tell you

CalibrationTreadmill speeds are not always accurate.
Very slow or fastThe 1% rule is tested in the middle range.
Outdoor fitnessHills and wind still need outdoor runs.

Questions

Common questions

What incline makes a treadmill like running outside?

1%.

How do I convert pace to treadmill speed?

60 divided by minutes per mile gives mph.

Is treadmill running easier?

At 0% slightly; at 1% it is about the same.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Before you push on

New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.