Does the iPhone count steps on a treadmill?

Yes, if the phone is on you. A treadmill trial measured the iPhone within 5% of hand-counted steps at 5, 7.5 and 10 km/h. What breaks the count is the habit, not the machine: a phone parked on the console feels almost nothing, because it is the phone that has to move, not you. Holding the handrails also lowers the count, since the motion reaching your pocket gets smaller.

Does the iPhone count steps while cycling?

No. Apple's Health app tracks steps and walking or running distance automatically, but cycling is not one of the activities an iPhone records on its own — you need a workout app or an Apple Watch for that. It also fits how step counting works: pedalling produces no heel strike, so there is no peak in acceleration for the phone to recognise as a step.

Does the iPhone count steps when it is switched off or the battery is dead?

Switched off by you: assume nothing is recorded. A flat battery is a different case, and a more interesting one. Steps are logged by a low-power motion coprocessor that keeps running with the screen off, and when an iPhone shuts itself down on a flat battery it still holds a little reserve charge. There are documented reports of the motion chip continuing to log for days after that shutdown, with the steps appearing once the phone was charged again. Apple does not document this as a feature, the best-known account is old, and it is not something to rely on — but it is why steps sometimes turn up for hours you thought were lost.

Does the iPhone count steps on an elliptical or when walking in place?

Walking in place usually counts, because your body still rises and falls the way it does when walking. An elliptical usually does not: the glide is smooth and your feet never strike the ground, so the sharp change in acceleration a step is recognised from never happens. Neither case has been measured for iPhones specifically — this follows from how step detection works rather than from a published trial, and this page marks the difference.

Why does my iPhone add steps in the car?

Because a rough road shakes the phone at roughly the rhythm of walking, and a step counter recognises steps from exactly that kind of repeated jolt. It is the same detector working correctly on the wrong input. The effect is small in ordinary driving and there is no published figure for how many steps an iPhone adds this way, so this page does not invent one.

what the iPhone counts as a step

One rule answers every version of this question: the phone counts a step when it feels a peak in the acceleration of the body carrying it. Not your legs — the phone. Everything below follows from that, including the cases where the answer is no.

What has been measured

Short list, because it is a short list. These are trials, not reasoning.

Cases with a published measurement. Sources: Duncan et al. 2018, JMIR mHealth 2019.
situation	counts?	what was found
Treadmill, phone on you	yes	within 5% of hand-counted steps at 5, 7.5 and 10 km/h
Ordinary days, phone in a pocket	yes	791 steps a day missing against a reference pedometer
Ordinary days, phone in a bag	partly	2,104 steps a day missing — the bag costs about 1,300

What follows from how it works

Nobody has published a trial for the cases below. Rather than guess at percentages, this table says what the mechanism implies and leaves it at that.

Cases with no published measurement — reasoned from how step detection works, not from a trial
situation	counts?	why
Phone on the treadmill console	no	you move, the phone doesn't
Walking in place	usually	your body still rises and falls
Elliptical	usually not	a smooth glide, no heel strike
Cycling	no	no heel strike, and Apple doesn't track it
Phone switched off by you	assume not	no documentation either way
Battery flat, phone shut itself down	sometimes	reserve charge — reported, not documented
Pushing a wheelchair	not as steps	a different movement, counted differently
Rough road in a car	may add extra	vibration looks like a walking rhythm

The treadmill, and the mistake everyone makes on it

A treadmill is not the problem. Carried on your body, the phone matched hand-counted steps to within 5% at three different speeds. The problem is the console: it is exactly where a phone ends up, and a phone lying still counts nothing while you walk five kilometres.

Holding the handrails costs you as well. The motion that reaches your pocket gets smaller, and smaller motion means fewer peaks that clear the threshold.

Cycling

No — and for two reasons that agree. Apple's Health app records steps and walking or running distance by itself; cycling is not one of the things an iPhone tracks on its own, and it needs a workout app or an Apple Watch. It also could not work: pedalling has no heel strike, so there is no peak for the detector to see.

When the phone is off, or the battery is dead

These are two different states, and the second one is stranger than it looks.

Switched off by you: assume nothing is recorded. Neither Apple nor anyone else documents what the motion chip does after a deliberate shutdown, and this page is not going to guess.

Battery flat: an iPhone does not run to zero — it shuts itself down while a little charge is left. There are documented accounts of the motion coprocessor continuing to log steps for days after that, with the count appearing once the phone was charged. Apple does not describe this as a feature, the best-known account is from an iPhone 5s in 2014, and nothing says today's hardware behaves the same way. Do not rely on it — but it explains the occasional surprise of steps turning up for hours you had written off.

This section was wrong when the page was first published: it said flatly that nothing is recorded in either case. That is true of a chip with no power at all, and it is not true of a phone that shut itself down with charge to spare. Corrected the same day.

Walking in place, and the elliptical

Walking in place usually counts: your body still rises and falls the way it does on a pavement, and that is the whole signal. An elliptical usually does not: the motion is a glide, your feet never strike anything, and the sharp change the detector looks for never arrives.

Both of those are reasoning, not measurement. No published trial has tested an iPhone on an elliptical, and this page would rather say so than invent a number.

Wheelchairs

Pushes are not steps, and Apple treats them as their own measurement rather than converting them into steps: on Apple Watch, wheelchair users get a count of pushes, with a choice of walking pace or running pace. An iPhone alone does not track pushes.

Extra steps in the car

A rough road shakes the phone at about the rhythm of walking, and a step counter is built to recognise exactly that kind of repeated jolt. It is not a fault so much as the right detector meeting the wrong input.

There is no published figure for how many steps this adds on an iPhone, so there is none here either.

What this means for the number on your screen

Angel Step shows the count Apple Health already holds, so it inherits exactly these rules — no more and no less. If the number looks lower than your day felt, the reason is usually in one of the tables above; if it disagrees with another device, why your step counts don't match explains which one Health keeps. And how accurate the count is answers the other half of the question: not whether a movement registered, but how close the total lands.

Sources

Apple, Core Motion — the motion coprocessor records movement in the background and keeps seven days of history. Apple Developer
Reported behaviour after a flat-battery shutdown — an iPhone 5s logging for four days on reserve charge. ⚠️ A single old account, not Apple documentation. iDownloadBlog, 2014
Apple — wheelchair users get a push count with a choice of pace. Apple Support
Duncan et al. (2018), Journal of Sports Sciences — treadmill and free-living validity of the iPhone step count. PubMed
Höchsmann et al. (2019), JMIR mHealth and uHealth — pocket against bag over seven days. JMIR