How to track your menstrual cycle (and what to do with the data)
Cycle tracking has a reputation for being either a fertility tool or an app that wants your data. It is neither, at its simplest: it is a record of your own pattern, which is what turns 'my periods are all over the place' into something specific enough to act on.
Count the days correctly
Day 1 is the first day of full bleeding. Spotting the day before does not count as day 1 — and getting this wrong is the most common reason a perfectly regular cycle looks erratic on paper.
Cycle length is the number of days from one day 1 to the next day 1, not the gap between the end of one period and the start of the next.
What to record
Bleeding
Which days, and roughly how heavy — light, medium, heavy, or how often you changed protection.
Pain
A simple 0–10 score and what you took or used for it. This is the single most useful column for a GP appointment.
Mood and sleep
One or two words a day is enough. Patterns show up across cycles, not within one.
Anything unusual
Bleeding between periods, unexpected pain, discharge changes — the things you would otherwise forget by the appointment.
Cervical mucus (optional)
Useful if you are trying to identify ovulation; skippable otherwise.
How long before it tells you anything
Three cycles is the practical minimum for a pattern, and six gives you a genuinely reliable picture including how much your cycle naturally varies.
What you get at the end of it: your typical cycle length and its range, which days you can expect to feel worst, and roughly when your next period is likely to arrive — enough to plan a holiday, a race, or a heavy week at work around.
Paper, notes app, or a tracking app
All three work. A tracking app gives you predictions and charts; a notes app or a paper diary gives you complete privacy over health data, which matters to plenty of people and is a perfectly good reason to choose it.
If you use an app, it is worth reading what it does with your data and whether it is stored or shared. If that gives you pause, a notebook does the same job with none of the question.
What the data is genuinely for
Better GP appointments
Three cycles of pain scores and bleeding notes is more persuasive than any description from memory, and it is what a diagnosis of conditions like PMDD or endometriosis is usually built on.
Planning
Knowing your hardest days a fortnight in advance is enough to move what can move.
Spotting change
A cycle that shortens or lengthens meaningfully, or bleeding that gets heavier over several months, only stands out against a baseline.
Never running out
The unglamorous one: knowing your start date means restocking before the bleed rather than during it.
When to speak to a GP
Bring your tracking to a GP if your cycle is consistently shorter than 21 or longer than 35 days, if periods stop for three months or more without pregnancy, if bleeding is very heavy, or if you bleed between periods or after sex.
This page is general information about menstrual health, not personal medical advice. For urgent concerns contact your GP or NHS 111.
Where Surreal Comfort fits
Our quiz asks about your cycle length and symptoms for exactly this reason: the delivery is timed to arrive before your predicted start date, not on a fixed calendar day.
Tracking your cycle — frequently asked
How do I track my menstrual cycle?
Record the first day of full bleeding as day 1, note bleeding, pain, mood and sleep each day, and count cycle length from one day 1 to the next. Three cycles will show a pattern; six will show how much it varies.
What day does a menstrual cycle start?
Day 1 is the first day of full bleeding, not the first day of spotting. Cycle length is measured from one day 1 to the next.
How many months of tracking do I need?
Three cycles is enough to see a pattern and is usually what a GP will ask for. Six gives a more reliable picture including your natural month-to-month variation.
Do I need an app to track my cycle?
No. A notes app or a paper diary records the same information, and keeps health data entirely private. Apps mainly add predictions and charts you could otherwise work out yourself.
Can cycle tracking predict my next period?
It can give a good estimate once you know your typical length, but ovulation timing varies with stress, illness and travel, so predictions are an estimate rather than a guarantee — and are not a form of contraception.