Contraction Calculator (5-1-1 Rule for Labor)
Enter how far apart your contractions are, how long each lasts and for how long the pattern has held to check the 5-1-1 rule and see whether it looks like early or active labor.
How it works
Contractions per hour = 60 ÷ interval (min) · Rest = interval × 60 − duration (s) · 5-1-1 rule: interval ≤ 5 min AND duration ≥ 60 s AND pattern ≥ 60 min
Contractions are timed from the start of one to the start of the next. The widely used 5-1-1 rule — contractions about 5 minutes apart, each lasting about 1 minute, for at least 1 hour — is the usual signal to call your maternity unit or head to the hospital in a first labor (ACOG). Early labor typically brings contractions 5–20 minutes apart lasting 30–45 seconds; in active labor they come every 3–5 minutes for 45–60 seconds, and in transition every 2–3 minutes for 60–90 seconds. If this is not your first baby, you live far away, your waters break or you have any warning signs, call earlier.
Worked example
Contractions start every 5 minutes, each lasts 60 seconds and the pattern has held for 60 minutes: 60 ÷ 5 = 12 contractions an hour with 5 × 60 − 60 = 240 s of rest between them. All three conditions are met, so the 5-1-1 rule is Met — call your provider or go to the hospital (an active labor pattern).
Sources: ACOG — How to tell when labor begins · NHS — Signs that labour has begun
Frequently asked questions
How do you time contractions?
Note the time when a contraction starts and when it ends. The duration is start to end; the frequency (interval) is from the start of one contraction to the start of the next. Time several in a row and use the averages.
What is the 5-1-1 rule?
Contractions coming every 5 minutes, lasting 1 minute each, for 1 hour. Many hospitals use it (or a 4-1-1 version) as the point to call and come in during a first labor. Follow the instructions your own care team gave you.
How can I tell Braxton Hicks from real labor?
Braxton Hicks contractions are irregular, do not get closer together and often ease when you change position, rest or drink water. True labor contractions become regular, stronger, longer and closer together no matter what you do.
When should I go to the hospital straight away?
Go immediately — whatever the contraction pattern — if your waters break, you have bleeding, the baby moves less, you have constant severe pain, a fever, or you are less than 37 weeks pregnant with regular contractions.
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This calculator is for education only and does not replace your midwife, obstetrician or doctor. Contact your care team straight away about bleeding, fluid leaking, reduced baby movements, severe pain or anything that worries you.