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RUNNERS LAB

Treadmill Board
Calculator

Enter belt km/h or mph and see distance finish clocks plus session distances from 15 to 90 minutes.

Last reviewed 25 August 2026

Set 12.0 km/h and the board shows 5:00 for 1 km, 25:00 for 5K, about 1:45:29 for a half, about 3:30:59 for a marathon, and 18.0 km in 90 minutes. Belt speed first. Distance clocks and session rows. Exact arithmetic, not a race predictor.

Belt speed

KM/H

The number on the treadmill deck.

Belt pace /km

5:00

  • Even belt speed

Belt pace /mile

8:03

  • 1.609344 km

Console

12.0 KM/H

  • 7.5 MPH
Treadmill pace

Short markers

1 km5:00
1 mile8:03

Session distance

How far at this belt speed if you never change it.

15 min3.00 KM
20 min4.00 KM
30 min6.00 KM
45 min9.00 KM
60 min12.00 KM
90 min18.00 KM

Road distances

Even-pace clocks at this belt speed. Not a race predictor.

5K25:00
10K50:00
15K1:15:00
Half marathon1:45:29
Marathon3:30:59

What this result means

A treadmill board starts from the console: type km/h or mph and read finish clocks for common road distances plus how far you cover in 15, 20, 30, 45, 60, and 90 minutes. It is belt-first like the treadmill pace chart, but with half marathon, marathon, and longer session blocks.

Use it when you are on a deck and want the full table from one belt setting. Use the compact treadmill pace chart for a quick 1 km–10K snapshot. Use the pace board when you think in min/km or min/mile and want ultra distances too.

At 12.0 km/h, 1 km is 5:00, 5K is 25:00, 10K is 50:00, half marathon is about 1:45:29, marathon about 3:30:59. In 30 minutes you cover 6.0 km; in 90 minutes, 18.0 km.

At 10.0 km/h, 5K is 30:00 and a 45-minute session is 7.5 km. Switch to mph and the same identity holds with 1.609344 km per mile.

Calculation method

Time = distance × (3600 ÷ km/h). Session distance = km/h × (minutes ÷ 60). Pace rows use the same belt identity as the treadmill pace calculator.

Exact arithmetic. No fatigue model and no incline adjustment on the board.

Holding a belt speed for a full marathon on a treadmill is still a human problem. The table assumes constant speed for the numbers you typed.

Full methodology →

Frequently asked questions

How long is a half marathon at 12 km/h?

About 1:45:29 if you never change the belt. That is 5:00/km even-pace arithmetic, not a prediction from a shorter race.

How far do I go in 90 minutes at 12 km/h?

18.0 kilometres. The board also lists 15, 20, 30, 45, and 60 minutes at the same belt speed.

How is this different from the pace board?

The pace board starts from pace or speed and includes ultras. This board starts from belt speed and stays on treadmill session markers plus road distances through marathon.

How is this different from the treadmill pace chart?

The chart is a compact subset: 1 km through 10K and 20–60 minute sessions. The board adds 15K, half, marathon, and a 90-minute row.

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