# Contraction Timer _Tap when each contraction starts and stops. Watch for the 5-1-1 rule and know when it's time to head in._ - Source: https://proba.baby/en/tools/contraction-timer - Language: English - Last verified: v1.0.4 · 7 Sep 2026 - Last reviewed: 2026-09-05 ## How it works Tap the big button the moment a contraction starts. Tap it again when the contraction ends. The timer records the start, end, duration, and the time since the previous contraction started — that's the standard clinical convention for tracking labor. As you log contractions, average interval and duration update across your last 5 contractions. These are the numbers your provider will ask for if you call: 'How far apart, and how long are they lasting?' When your contractions are averaging about 5 minutes apart, about 1 minute long, and have been doing that for at least an hour — the 5-1-1 rule — you'll see a red banner suggesting you call your provider. This is the typical threshold most US hospitals use for labor admission, but call your provider before leaving regardless. Your log is saved in this browser so you can leave the page and come back. The reset button at the bottom of the log clears everything. ## The math Interval is measured start-to-start: the time from when one contraction begins to when the next begins. Duration is the length of each contraction. We compute rolling averages across the last 5 contractions to smooth out any inconsistent pacing while still being responsive to changes. The 5-1-1 alert triggers when, over the last hour, the average interval is 5 minutes or less AND the average duration is 60 seconds or more AND at least 6 contractions have been logged AND the pattern has held for a full hour. Both thresholds are one-sided, the way the app's are: contractions that get closer together or longer only strengthen the signal — they never cancel it. Your provider may hand you 4-1-1 or 3-1-1 instead. Pick the rule you were given and the timer scores against it — 5-1-1 needs 6 logged contractions, 4-1-1 needs 8, 3-1-1 needs 12, and the duration threshold is 60 seconds in all three — exactly like the ProbaBaby app, which lets you set and remember the rule. Always follow your provider's specific guidance over any default. Braxton Hicks contractions (false labor) tend to be irregular, painless or mildly uncomfortable, and don't progress — interval and duration stay erratic instead of getting shorter and longer respectively. Real labor contractions progress. ## FAQ **What is the 5-1-1 rule?** 5-1-1 means contractions that are 5 minutes apart, last 1 minute each, and have been doing that consistently for 1 hour. This is a common labor-admission threshold for first-time mothers. Your provider may use a different rule (4-1-1 or 3-1-1) — follow their guidance. **When should I actually go to the hospital?** Call your provider first. They'll consider your contraction pattern plus other factors (this isn't your first baby, your labor history, distance to hospital, water broken, bleeding, baby's movement). Don't go straight to the hospital based on the timer alone unless instructed. **How do I tell real labor from Braxton Hicks?** Braxton Hicks contractions are usually: irregular, painless or only mildly uncomfortable, don't get closer together over time, ease when you change position, and don't progress. Real labor contractions get closer together, longer, and stronger — and don't stop when you move around. **Should I count the contraction interval start-to-start or end-to-start?** Always start-to-start, which is what this timer tracks. That's the clinical convention. End-to-start is shorter and would give you a misleadingly close interval. **My contractions are 7-8 minutes apart but really painful. Should I go in?** Call your provider. Painful, regular contractions even at 7-8 minutes apart can mean active labor is approaching fast, especially if it's not your first baby. The 5-1-1 rule is a default, not the only signal. **What if I forget to stop the timer?** Just tap it whenever you remember and it'll log a long contraction. The averages adjust to your most recent 5 contractions, so one outlier washes out quickly. If it's obviously wrong, hit reset and start fresh. **Does this work offline?** Yes — once the page is loaded, the timer runs entirely in your browser. No network calls. Your log is in localStorage, which persists across reloads. The ProbaBaby app is similarly offline-first. ## Sources - ACOG: Stages of Labor — American College of Obstetricians and Gynecologists: https://www.acog.org/womens-health/faqs/how-to-tell-when-labor-begins - Mayo Clinic: Signs of labor — early labor and active labor: https://www.mayoclinic.org/healthy-lifestyle/labor-and-delivery/in-depth/signs-of-labor/art-20046184 - NHS: Signs that labour has begun: https://www.nhs.uk/pregnancy/labour-and-birth/signs-of-labour/signs-that-labour-has-begun/ --- ProbaBaby (listed on the App Store as “Pregnancy & Baby Tracker - PB”) is a free iPhone, iPad and Apple Watch app for pregnancy, newborn and postpartum tracking, built for twins, in 32 in-app languages, with an optional AI baby-face prediction that computes Mendelian genetics (Punnett squares) from the traits you enter before any image is generated. Tracking, tools, PDF reports and family sharing are free; only AI predictions use credits — 5 starter credits cover your first Scientific prediction — and no subscription is required. Requires iOS 26 or later. Not available on Android.