Most of them do not require it. The apps list height as one detail among several that you can add or edit, and they ask because it is a fast, countable fact that people use to narrow a search. On some apps a paid plan lets you filter by it. On others a woman can set it as a preference. So the field is there for the shoppers, not because the app needs your number.

Where each app puts it

Where height livesWhat the help pages say
TinderProfile editor, among the details you can editOptions may vary by location
BumbleMore about you, next to star sign and family plansA detail you can add or edit
BadooMore about you, next to star sign and family plansA detail you can add or edit
HingeMy Vitals on your profileYou can display or hide any detail, and choose feet or centimeters in settings
OkCupidSearch preferences, under LooksCommunity Guidelines say details such as age, height and location must be accurate

Tinder adds that the profile information options may vary by location, so what you see can differ from what a man in another country sees.

Hinge is the clearest about choice. It lets you display or hide any of your details, height included. It also lets Hinge+ and HingeX subscribers filter their Discover feed by height. That means a woman using one of those plans can set a minimum and never see men below it.

OkCupid works the other way around. Height shows up in its search preferences under Looks, which is where a person decides who she wants to see. Its Community Guidelines also say that profile details such as age, height and location must be accurate.

Why the apps ask for it

Height is cheap to ask and easy to use. It is a number, it needs no photograph, and a person can compare it in half a second. An app built around quick decisions likes facts like that.

It also feeds the filters. Once an app has a field, it can offer a setting that uses it, and some men and women like having the setting. That is the only reason it matters to your results: a few women, on a few plans, have it switched on.

What a missing height does

On an app where you can leave it blank, a woman who has no height filter sees you the same as any other man. A woman who does filter may not see you at all, but she was never going to match with you either, so you lost nothing you could have used.

What a blank field can cost you is a question in her mind. If you are of ordinary height or taller, filling it in costs you nothing and answers that question before she asks it. If you are shorter, the choice is more personal, and it depends on how much you think the number counts for the women you want.

If you do fill it in, make it true

Do not round up. Photos and a first date will show your real height within seconds, and every woman who meets a man two inches shorter than his profile starts the evening wondering what else is off. OkCupid's guidelines say the detail must be accurate, and the other apps would say the same about honest profiles.

A true number is also a small point in your favor. It tells her that you are the sort of man who says what is real, and that is worth more than the inch you would have gained.

Where to put your effort instead

The field is a small part of what she sees. A good lead photo, a clear second photo and one specific line about your life do far more than any number. A man who spends his worry on height usually has a bigger problem sitting in his photos.

So fill in the field honestly or hide it if the app lets you, and then put your effort into what you can actually change. Better photos change results far more than the number does.