How to Time Contractions

By the Contraction Timer editorial team · Written to align with guidance from ACOG, Mayo Clinic and the NHS · Last updated 7 July 2026

Timing contractions comes down to two numbers: how long each one lasts, and how far apart they are. This guide shows you exactly how to measure both, how many to time, and what the pattern is telling you.

The two numbers you're measuring

Every contraction has two measurements, and they answer different questions:

• Duration — how long a single contraction lasts, measured from the moment it starts building until it fully eases off. This tells you how strong and established labor is.
• Frequency (also called the interval) — how far apart contractions are, measured from the start of one contraction to the start of the next. This tells you how close together they are coming.

A pattern such as the widely used 5-1-1 rule combines both: contractions about 5 minutes apart (frequency), each lasting about 1 minute (duration), sustained for at least 1 hour.

How to time contractions, step by step

1. When a contraction begins, note the time (or tap "start").
2. When that same contraction ends, note the time again (or tap "stop"). The gap is the duration.
3. Wait for the next contraction to begin, and note that start time. The gap between the two start times is the frequency.
4. Repeat for several contractions in a row so you can see the pattern build.

Why you measure "start to start"

It is natural to think of the gap between contractions as the "rest" period — the end of one to the start of the next. But the standard measurement, and the one every clinical guideline uses, is start-to-start. Measuring start-to-start keeps the number consistent even as contractions get longer, and it is what your provider means when they ask "how far apart are they?" The timer measures start-to-start automatically.

How many contractions should you time?

Time several in a row, not just one. A single contraction tells you very little; the useful signal is the trend over about an hour:

• Are they getting longer?
• Are they getting closer together?
• Are they getting stronger?

Contractions that steadily do all three are more likely to be true labor. Contractions that stay irregular, or ease off when you move around, rest, or drink water, are more likely to be false labor (Braxton Hicks). ACOG suggests exactly this test: if resting and drinking water make the contractions go away, they are probably not true labor.

What the numbers mean

Early (latent) labor usually brings shorter, milder, irregular contractions that may be 10–20 minutes apart. As labor becomes active, contractions typically move closer to 3–5 minutes apart, last around 45–70 seconds, and grow stronger and more regular. Many hospitals ask first-time parents to head in around the 5-1-1 pattern, but your own provider's instructions always come first.

Read next: The 5-1-1 rule explained and when to go to the hospital in labor.

Timing by hand vs. using an app

You do not need any app — a clock and a piece of paper work. But labor is not a great time for arithmetic, and small errors add up. A timer helps by:

• Recording each start and stop with a single tap.
• Calculating duration and start-to-start interval automatically.
• Averaging recent contractions so you can see the pattern, not just one data point.
• Producing a clean summary you can read aloud to your provider or hand to your midwife.

Contraction Timer does all of this for free, with no ads or sign-up, works offline, and keeps every log on your own device.