Two numbers on a treadmill's specification say most about how it will feel to use: the motor and the running deck.
Motor power
Treadmill motors are usually quoted in horsepower (HP) or kilowatts. Check whether the figure is continuous duty, which is the power the motor can hold for the length of a workout, or a peak figure, which is higher and cannot be sustained. If a listing does not say which it is, the manufacturer's specification is the place to look.
As a rule of thumb, a higher continuous-duty rating gives the motor more headroom at higher speeds, with heavier users and when several people share the machine. If the treadmill will mostly be used for walking, a smaller motor can be enough.
Deck size
The running deck is quoted as length by width, in centimetres or inches. Length matters most for running: a longer deck leaves room for a longer stride at speed. A common rule of thumb is a deck of about 140 cm (55 in) or more for running, and taller users or those with a long stride may want more. Walking needs less. Width affects how much room you have side to side.
Other figures to compare
- Maximum user weight.
- Speed range and incline range, and whether the incline is motorised.
- Whether it folds, and its length and width both in use and folded.
- Console, screen size and which apps it works with.
- Power supply and warranty terms.
Every figure above is listed on the product page when the manufacturer publishes it. If a figure is not shown, it is because we have not been able to confirm it from the manufacturer.