Guide
How to ask without making it strange
All you want is one date: the day her last period started. It feels like a bigger question than that because hardly any man asks it, so you've got nothing to copy and you fill the gap with the worst outcome you can imagine. The gap is what this page is for.
Why it feels strange, and why it isn't
Her friends ask her this. So does her doctor, and so does the app on her phone, every single month. You're the one person in her life treating it like a state secret.
The subject isn't what makes a question awkward. The build-up is. Two minutes of "so, um, don't take this the wrong way" tells her something loaded is coming, and then she braces for it. Ask the way you'd ask what she wants for dinner and she'll answer the same way.
Get the timing right
The easiest time to ask is when it's already on the table. She cancels because she feels rough, or she's on the couch with a hot water bottle, or you're sitting there picking dates for a trip. In any of those the question is just the next thing you'd say anyway.
Then there's the version that goes badly: a text at 2am, or five minutes into a disagreement. Ask mid-argument and it isn't a question, it's an accusation with a question mark on it. She'll hear that.
Six lines that work
Pick the one that matches how long you've known her. The top of the list assumes you've been seeing each other a while; the middle ones are fine on a third date.
"When did your last period start? I keep track so I stop planning stuff on bad days."
The reason sits inside the same sentence, so she doesn't have to wonder what you're doing with it. You're asking for a date, not opening a conversation.
"Are you due soon? You seemed wiped out this week."
Use this when you actually noticed something. You're following up on a real thing you saw, which is very different from starting a file on her.
"I'm booking that weekend, is there a week that's bad for you?"
The softest one on the list. Half the time she gives you the dates herself and it never sounds like anything but planning.
"Do you get bad cramps, or is it a non-event for you?"
This asks about her, not her calendar. The date usually falls out of the answer anyway.
"Tell me what actually helps when you're on it, so I stop guessing."
It isn't a question about dates at all. It's also the one that buys you the most goodwill, by a distance.
"What day are you on?"
Save this for after she's told you once. Between two people who already talk about it, it's a two-second check-in.
What to do when she answers
Say thanks and write the date down. You asked for one thing and you got it, so resist the four follow-up questions; that's the point where a normal exchange starts feeling like an interview.
Write it down the same minute, not later. Telling her you keep track and then asking again three weeks on is worse than never having asked.
If she asks why you want to know
One sentence: you'd rather plan around it than get it wrong. It's true, and it works the same whether she's the only woman you're seeing or one of three.
What that date really buys you is a week where you're not confused. A bad mood reads as a bad week instead of something you did, and you quit booking the big night on the worst day of the month. Selfish reason, sure. It's still the honest one, and it holds up better than pretending you did it for her.
Lines to skip
- "Are you on your period?" in the middle of an argument. At that point you've stopped discussing whatever you were discussing and started grading her mood.
- "Someone's hormonal." No version of this has ever gone well for anyone.
- Asking three times in a month because you never wrote it down.
- Quoting it back at her. "You're in your luteal phase" helps nobody.
- Selling it as something you're doing for her. It's for you. Say that.
What they have in common is announcing it. Knowing where she is in the month should make you easier to be around that week. Nobody needs to hear that you did the arithmetic.
Now put the date somewhere
A date you're keeping in your head is a date you'll lose. Seeing more than one woman, you'll lose it faster, and sooner or later you'll swap two of them around. That one is hard to explain your way out of.
For Men: Period Tracker gives every woman her own profile with her own cycle, and shows you which phase each of them is in today. One date each, entered once. It all sits in local storage on your phone, so there's nothing to log into and nothing on a server with their names on it.
If you want the background on what the phases actually mean, read why men should track her cycle.
Common questions
Is it weird to ask a woman when her last period was?
It's fine if you ask it plainly and say why. What makes it weird is asking out of nowhere, asking again a week later because you forgot, or making a joke out of the answer.
How do I ask a girl about her period over text?
Keep it to one line. Something like: "Random one, when did your last period start? I'd rather know than guess when you're feeling rough." No build-up and no apology in front of it.
What do I actually need from her?
One date. The day her last period started. The tracker handles the counting from there.
What if she asks why I want to know?
Tell her the truth in one sentence: you'd rather plan around it than get it wrong. Then stop talking about it.
Get the app
Free on iPhone, no sign-up, every date you enter stays in local storage on your device.
Cycle lengths and symptoms vary from person to person. This is general information about how cycles work, not medical advice.