Contraction timer
Tap when a contraction starts and again when it eases off. You get the length of each one, the gap from the start of one to the start of the next, a rolling average of your last five, and whether the 5-1-1 rule is met — with the UK, US and Australian triggers named separately, because they genuinely differ.
Contraction timer
No sign-up · PrivateThe point at which you are asked to call genuinely differs. 5-1-1 is a US convention; the NHS asks you to call once contractions come every 5 minutes or more often; Australian guidance counts 3 in 10 minutes.
Nothing timed yet
What this measures: How long each contraction lasts, how long from the START of one to the START of the next, and a rolling average of your last 5 of each.
Where you are (NHS): Call your midwife or maternity unit when your contractions are coming every 5 minutes or more often. That is the NHS trigger, and it is deliberately simpler than 5-1-1 — there is no one-minute length to reach and no hour to wait out.
Nothing you type leaves your device. The whole calculation runs in your browser.
How this is calculated
FormulaHow the timing works
Two taps per contraction: one as it begins, one as it eases off. From those two moments everything else is subtraction.
- Length = the moment you tapped it ended − the moment you tapped it started.
- Interval = the start of this contraction − the start of the one before it. Start to start, not end to start. Every published threshold in every country is written start-to-start, so measuring the rest gap instead makes contractions look further apart than they are. The tool shows the rest gap too, in its own column, but never uses it for a rule.
- Rolling average = the mean length of your last 5 finished contractions, and the mean of your last 5 intervals. Five is short enough to follow a pattern that is changing and long enough that one odd contraction does not throw it.
The 5-1-1 rule, stated exactly
5-1-1 means contractions coming 5 minutes apart or closer, each lasting at least 1 minute, with that pattern holding for 1 hour. It is a United States convention, taught by US hospitals and childbirth educators. It is not published as a rule by ACOG, it is not how the NHS phrases the question, and Australian services phrase it differently again.
The check runs like this. Starting from your most recent finished contraction, the tool walks backwards through the log and keeps going while every step still obeys both halves of the rule — each start-to-start gap 5 minutes or less, and each contraction at least 1 minute long. The moment either condition fails, the run stops there and starts again from that point. The run’s length is measured from its first start to its last start, so 5 minutes apart for a full hour means 13 contractions and 12 gaps. 5-1-1 is reported as met only when that span reaches 60 minutes.
That is the strict reading, and it is deliberate. It is safe to be strict here only because the verdict at the top reports the strongest trigger currently met rather than 5-1-1 on its own, so a single short contraction breaking the run can never be the reason someone sits waiting instead of ringing.
The other two thresholds, because 5-1-1 is not universal
- NHS (UK). Call your midwife or maternity unit when contractions are “coming every 5 minutes or more often”. There is no one-minute length and no hour to wait out, so this trigger fires earlier than 5-1-1. The tool tests it as: at least three intervals recorded, and the last three all 5 minutes or less.
- Pregnancy, Birth and Baby (Australia). Go to hospital or the birth centre with “at least 3 contractions in 10 minutes for your first labour”, when they are getting stronger and taking more of your focus; contact the birth unit once contractions are painful and regular, meaning 2 or more in 10 minutes. The tool counts contraction starts inside the trailing 10 minutes.
- ACOG (US). Time the contractions; true-labour contractions come at regular intervals and get closer together, and the pain usually starts in the back and moves to the front. Call your ob-gyn if you think you are in labour or are not sure.
Two urgent checks the timer can do on its own
The NHS lists two things about the pattern itself that mean call now, and both are arithmetic the tool can see:
- Any contraction lasting longer than 2 minutes. Checked on every contraction in the log, including one that is still running.
- 6 or more contractions in every 10 minutes. Checked across every 10-minute window in the log, not only the most recent one, so a burst twenty minutes ago is still reported.
When either fires, the verdict changes to “Call your maternity unit now” and outranks every pattern rule on the page.
What the timer cannot check
The reasons to call that matter most have nothing to do with the pattern, so they are listed above the button rather than underneath the result, and they never disappear: waters breaking, any vaginal bleeding, the baby moving less than usual or differently, being under 37 weeks and possibly in labour, constant severe pain with no let-up between contractions, fever, a bad headache or vision changes, or simply feeling that something is wrong. None of those waits for an hour of contractions and none of them is affected by what this tool says.
All arithmetic is whole milliseconds from your device clock, done in your browser. An event whose end is earlier than its start — two “ended” taps in a row, or a clock that jumped — is discarded rather than turned into a negative length, and the log is kept in this browser’s own storage so an accidental refresh does not lose it.
Two taps, and then some arithmetic
Timing contractions is one of the few genuinely useful things you can do in early labour, and it is also one of the easiest to do badly. The two mistakes are almost universal. The first is timing from the end of one contraction to the beginning of the next, which feels natural — that is the bit where nothing is happening — but every threshold ever published is written start to start, so measuring the gap instead makes your contractions look further apart than they are. The second is treating the numbers as the thing that decides.
This tool does the first part properly and is honest about the second. Tap when a contraction begins, tap again as it eases off. It shows how long each one lasted, how long from the start of one to the start of the next, a rolling average of your last five of each, and where that pattern sits against the rule you have probably been given.
5-1-1 is American
If you have read anything about when to go in, you have met 5-1-1: contractions five minutes apart, lasting one minute, for one hour. It is clear, memorable, and it is a United States convention. ACOG does not publish it as a rule. The NHS does not use it. Australian services do not use it either.
What the NHS actually says is simpler and fires earlier: call your midwife or maternity unit when your contractions are “coming every 5 minutes or more often”. No minimum length. No hour of waiting. If you have spent the evening trying to accumulate sixty minutes of textbook 5-1-1 before you felt entitled to phone, that hour was invented somewhere other than your maternity unit.
Australia frames it as a rate rather than an interval. Pregnancy, Birth and Baby, the Australian government’s maternity service, says to go to hospital or the birth centre with “at least 3 contractions in 10 minutes for your first labour”, when they are getting stronger and taking more of your focus — and to contact the birth unit once contractions are painful and regular, meaning two or more in ten minutes.
Three countries, three different lines, same underlying labour. This is why the tool asks where you are and names the body it is quoting, rather than averaging them into a rule that belongs to nobody.
The latent phase is not the timer failing
Before established labour there is a latent phase, and the NHS describes it plainly: there is “no set pattern to how many contractions you get or how long they last”. It is usually the longest stage, and it can take hours or, occasionally, days. A log full of contractions that are 4 minutes apart, then 11, then 6, then 9 is not a broken pattern. It is the normal one.
Established labour is reckoned from the cervix being dilated to about 4 cm with regular contractions. From there to fully dilated is usually 8 to 18 hours in a first pregnancy, and often 5 to 12 hours in a second or third. No timer can tell you which side of that line you are on, because the only thing that can is an examination.
True labour, false labour
ACOG gives the most usable test for the difference. True-labour contractions come at regular intervals and get closer together over time, and the pain usually begins in the back and moves round to the front. False-labour pain is usually felt only in the front, and — the useful part — it tends to ease off if you rest and drink some water. If resting and hydrating make them stop, they were not true labour contractions.
Braxton Hicks contractions do the same thing. They can be strong enough to be convincing, particularly late on, and the honest answer is that plenty of people cannot tell until the pattern either builds or does not. Timing for an hour is a reasonable way to find out. Waiting three hours in pain to be sure is not.
The things that do not wait for a pattern
This is the part of the page that matters most, and it is the part a timer is worst at, because it has nothing to do with the numbers.
Call your maternity unit straight away, whatever the log says, if your waters break or you think they might have; if you have any vaginal bleeding; if your baby is moving less than usual or the pattern of movements has changed; if you are less than 37 weeks pregnant and think you might be in labour; if the pain is constant and severe with no let-up between contractions; if you have a fever, a bad headache, vision changes or pain under your ribs; or if you simply feel that something is wrong.
The NHS adds two that this tool checks for you: call if any contraction lasts longer than 2 minutes, or if you are having 6 or more contractions every 10 minutes. And call 999 if you think your baby is coming now and you have a strong urge to push.
What a good log cannot tell you
A tidy five-minute pattern is not a promise that labour is progressing, and a messy one is not a sign that it is not. People arrive in established labour with a chaotic log and people spend an entire day at a textbook interval in the latent phase. Dilation is not visible from the outside, and no app has ever measured it.
The strongest predictor of when to go in is not on this screen at all. It is how you are coping, how far you have to travel, what happened last time, and what your own midwife or doctor told you to do. If you have been asked to come in early — a previous fast labour, a long journey, group B strep, twins, a planned VBAC, any high-risk flag — that instruction outranks every rule of thumb on this page.
If the taps start slipping
At some point in labour, timing stops being possible and stops being useful. Nobody has ever been turned away for ringing without a neat log, and no maternity unit has ever asked to see one. Triage lines are answered 24 hours a day and expect calls from people who are not sure. If you cannot get through, in the UK call 111; in the US go to your labour and delivery unit; in Australia go to your nearest hospital birthing or emergency unit.
Put the phone down and use it. That is the whole point of having timed anything.
Sources
- Signs that labour has begun — NHS, accessed
- The stages of labour and birth — NHS, accessed
- Signs of going into labour — NHS (Best Start in Life), accessed
- How to Tell When Labor Begins — American College of Obstetricians and Gynecologists, accessed
- Going to hospital or birthing centre — Pregnancy, Birth and Baby (healthdirect Australia), accessed
- Giving birth — contractions — Pregnancy, Birth and Baby (healthdirect Australia), accessed