Do under-desk bikes actually do anything?

Listings in this category promise a workout while you work. Read the specifications and that claim has nothing behind it: there is no published resistance range on most of these machines, no way to measure your effort, and a seating position that limits how hard you can push without sliding your chair backwards.

The true claim is smaller and it is genuinely worth something. Sitting still for eight hours and sitting with your legs turning slowly for four of them are different days. The machine converts time you were already going to spend seated into time spent moving, at zero scheduling cost — and unlike a walking pad it asks nothing of your floor, your posture or your typing accuracy.

That is the frame we would buy one on. Anything more than that and the machine will disappoint you by about week three. Where the intensity line actually sits.

A seated under-desk machine has no sensor pointed at you. It does not know your body mass, your fitness or your heart rate, and most of them do not publish a resistance figure in units that mean anything.

The exception is worth naming, because it is the only quantitative statement in the category: DeskCycle publishes eight magnetic levels up to a stated 39 lb of resistance. Cubii publishes a level count with no range; Stamina publishes “adjustable tension” with no count at all. So of the machines we track, exactly one lets you compare how hard it gets in any numerical way.

Which means any calorie number on a small display is a formula applied to pedal revolutions, with your body treated as a constant it was never told. That is the same problem walking pads have, and for the same reason. What a console can and cannot know.

Here is the argument for a seated machine that has nothing to do with fitness and is the strongest thing on its side of the ledger: there is no footfall.

Your feet stay on the pedals through the whole stroke. Nothing lands, which means no impact energy is delivered into the floor structure. In an apartment that is the mechanism behind essentially every complaint about home cardio — not motor noise through the air, but structure-borne thumping through the slab. Why the decibel figures in this category answer the wrong question.

Two other things follow from the same geometry. A seated machine cannot be fallen off, which matters if balance is a factor. And it does not raise you, so it has no effect on your desk height — the arithmetic that rules a walking pad out of many rooms does not apply. The desk-height arithmetic a pad requires.

Height. Not resistance, not levels, not the app — height, and then the knee travel above it.

Published heights across the seated machines we track run from 9.5 in (Cubii Move) to 11.38 in (Stamina InMotion E1000). Your knee well has a fixed clearance and the machine plus your moving knee has to fit inside it. Neither figure is on the box, and no maker publishes a stride length you could use to calculate the second one.

That is why fit failures rather than quality complaints dominate returns in this category, and why the DeskCycle’s published fit statement — that the standard model suits a 27 inch desk for a user around 5 ft 8 in or shorter — is worth more than any feature on the page. The four measurements to take before ordering.

For three different constraints. We have used none of them; every figure is published and sourced below, and the prices in the buttons are live rather than authored.

Best documented fit: the DeskCycle, 10 in tall, the only machine here whose maker tells you what desk and what user height it suits, and the only one publishing a resistance range rather than just a count.

Most complete specification: the Stamina InMotion E1000, the only seated machine whose maker publishes dimensions, product weight and a 250 lb user capacity together. It is also the tallest at 11.38 in, which is the catch.

Cheapest way to find out if you will use one: the Sunny mini pedal exerciser, which has the emptiest specification sheet on this site and the lowest price of entry. If you are not sure the habit will stick, finding out cheaply is a legitimate strategy.

The full pedal exerciser ranking and the ellipticals, which keep the knee lower through the stroke.

We have not pedalled any of these machines, measured a heart rate, or compared energy expenditure between a pedal exerciser and a walking pad. Anyone publishing that comparison from a spec sheet is inventing it.

We have published no calorie figures, for the reason set out above: the machine does not know your body mass and neither do we. Our full method. This page is general information about published specifications, not medical or fitness advice.