Contraction timer

What the numbers mean

Two numbers describe a contraction pattern: how often (frequency) and how long (duration). Frequency is the time from the start of one contraction to the start of the next, and duration is how long each one lasts, both best written down in seconds. Cleveland Clinic advises exactly that, and adds that writing down the time and length is “extremely helpful” when you describe the pattern to your provider. This timer does the arithmetic for you: it averages the gaps and the lengths, looks at the last hour on its own (the 5-1-1 guide is about a steady pattern over an hour), and compares it with the 5-1-1 guide.

The 5-1-1 check, step by step

The guide has three parts and the calculator tests each one on the contractions that started in the last 60 minutes of your list. 5: the average gap is 5 minutes (300 seconds) or shorter. 1: the average length is 1 minute (60 seconds) or longer. 1: the list spans at least 60 minutes. Each line in the result shows your number next to the limit with a tick or a cross, so you can see which part is missing instead of reading a bare yes or no.

A worked example

Take 14 contractions that began every 5 minutes from 10:00:00, each lasting between 62 and 66 seconds. The gaps are all 5:00, so the average is 5:00; the average length is 64 seconds; and the list covers 65 minutes, more than an hour. In the last 60 minutes there are 13 contractions, with an average gap of 5:00 and an average length of 64 seconds. All three parts pass, so the timer says the pattern fits 5-1-1 and it is time to call. Compare early labor: three contractions at 2:00, 2:42 and 3:20 PM lasting about 30 seconds average a gap of 40:00 and a length of 30 seconds, nowhere near 5-1-1, which is normal at that stage.

Common mistakes

Timing from the end of the contraction. The gap that matters runs from the start of one to the start of the next. Measuring from end to start understates the gap by the length of the contraction.

Timing too briefly. The “1 hour” in 5-1-1 means the pattern has been steady for an hour. Three contractions at five-minute gaps in a quarter of an hour can come from Braxton Hicks contractions, which ACOG notes can be painful and can make you think you are in labor when you are not.

Waiting for the rule when something else is wrong. ACOG’s reasons to go to the hospital do not depend on timing: water broken without contractions, heavy bleeding, constant severe pain with no relief, or less fetal movement.

Limits of this method

5-1-1 is a rule of thumb, not a medical standard. We could not find it in ACOG’s patient pages; Cleveland Clinic states “every five minutes for at least one hour” in one article and “about 60 seconds and every three to five minutes” in another, and says that providers have different criteria. ACOG advises asking your provider well before the due date what the right time to call is, and planning the trip to the hospital with the distance and traffic in mind. Follow their number over this page’s.

Seconds matter and so does honesty. The timer is only as accurate as the times you type. Use a clock with seconds, start the clock when the tightening begins and write the length when it eases.

It cannot see labor. ACOG notes that sometimes the only way to tell false labor from true labor is a vaginal exam that shows changes in the cervix. Only your care team can do that.

What is the 5-1-1 rule for contractions?

It is a rule of thumb that many obstetric practices teach: contractions about 5 minutes apart, each lasting about 1 minute, for at least 1 hour. Cleveland Clinic’s guide to labor says it as “every five minutes for at least one hour.” Providers set their own criteria, and some use closer or looser numbers, so ask yours which pattern they want before your due date. The rule is about when to call, not when the baby will arrive.

How do I time a contraction correctly?

Count from the start of one contraction to the start of the next, not from the end of one to the start of the next. Cleveland Clinic recommends noting the start time and the length in seconds. The length is how long the belly stays hard or the cramp lasts. The gap between starts is the number providers ask for: if one begins at 3:00 and the next at 3:05, they are 5 minutes apart whether each lasted 40 seconds or 70.

How do I tell real labor from Braxton Hicks contractions?

ACOG’s guide lists the differences. True labor contractions come at regular intervals and get closer together over time, last about 60 to 90 seconds, continue when you rest or move, steadily get stronger, and the pain usually starts in the back and moves to the front. False (Braxton Hicks) contractions have no pattern, do not get closer together, may stop when you walk, rest or change position, stay weak or fade, and are felt only in the front. ACOG also notes that sometimes only a vaginal exam showing changes in the cervix can tell the difference.

When should I call my provider or go to the hospital besides contractions?

ACOG says to go to the hospital if your water has broken and you are not having contractions, if you are bleeding heavily from the vagina, if you have constant, severe pain with no relief between contractions, or if you notice the baby moving less often. It also says: if you think you are in labor, or are not sure, call your ob-gyn or other obstetric care provider. Do not wait for the timer to say 5-1-1 if any of these happens.

What if I am less than 37 weeks pregnant?

Different advice applies. The NICHD says a woman concerned about preterm labor should call her health care provider or go to the hospital to be evaluated, and in particular should call if she has more than six contractions in an hour or if fluid or blood leaks from the vagina. Enter your weeks in the calculator and it will flag more than six contractions in the last hour before 37 weeks. Do not wait for a 5-1-1 pattern.

How long and how far apart are contractions in early and active labor?

Cleveland Clinic gives rough ranges: in early labor contractions may last 20 to 30 seconds and come every 30 to 60 minutes, feeling like an ache or pressure; in active labor they last 40 to 70 seconds and come every three to five minutes and can be so intense that you cannot talk or walk; in the second stage they come every two to five minutes and last about 60 to 90 seconds. These are typical ranges, and ACOG points out that every labor is different.

How long does labor take?

ACOG says labor typically lasts 12 to 18 hours for a woman having her first baby and 8 to 10 hours for women who have given birth before, and that every woman is different. Cleveland Clinic says your provider will likely tell you that you can be at home for early labor, but that you should be ready to go to your birthing center and be there during active labor.

Is a phone app or this timer enough on its own?

No. A timer records what you tell it. It cannot feel your cervix, hear the baby’s heartbeat or notice that something is wrong. Use it to describe your pattern clearly when you call, and let your provider decide what to do.

More for pregnancy: the due date calculator, the pregnancy week calculator, the kick count calculator, the pregnancy weight gain calculator and the pregnancy calories calculator.

Sources, read October 27–28, 2026: American College of Obstetricians and Gynecologists, “How to Tell When Labor Begins” (patient FAQ, last reviewed November 2025) (true versus false labor, the signs to go to the hospital, length of labor); Cleveland Clinic, “Stages of Labor” and “Contractions” (medically reviewed August 2024) (how to time contractions, typical ranges, the five-minutes-for-an-hour wording); Eunice Kennedy Shriver National Institute of Child Health and Human Development, “How do health care providers diagnose preterm labor?” (more than six contractions in an hour). The Mayo Clinic page on the stages of labor could not be opened and is not cited. This calculator is not endorsed by or affiliated with ACOG, Cleveland Clinic or the NICHD.

For general information only — not medical advice, and not a tool for patient care decisions. Talk with your ob-gyn or midwife about when to call and where to go. How we check our calculators.