Fundal Height Calculator

Compare your fundal height (pubic bone to top of the uterus) with your gestational age. Between 20 and 36 weeks the measurement in centimeters is usually within 2 cm of the number of weeks. Example: 28 weeks pregnant with a measurement of 27 cm is within the expected range of 26 to 30 cm.

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Gestational age (weeks)

Fundal height measured (cm)

How to use the Fundal Height Calculator

Enter the values in the fields.
Press Calculate to see the result with the steps shown.

Formula and method

Expected fundal height (cm) = gestational age in weeks, plus or minus 2 cm, from about 20 to 36 weeks.

Expected fundal height by week

Weeks	Expected (cm)
20	18 to 22
24	22 to 26
28	26 to 30
32	30 to 34
36	34 to 38

How fundal height is measured

You lie on your back with an empty bladder. A tape runs from the top of the pubic bone over the curve of the belly to the top of the uterus, measured by a clinician.

Why it can be off

Larger than expected: twins, extra fluid, a large baby or wrong dates. Smaller: a small baby, low fluid or a baby that has dropped. Ultrasound clarifies.

What it replaces and what it does not

It is a simple checkup tool and does not replace ultrasound estimates of growth. This calculator is for education and is not medical advice. Your own doctor, midwife or pediatrician should guide decisions about your care.

Frequently asked questions

What is fundal height?

Distance from the pubic bone to the top of the uterus.

What is normal fundal height?

Weeks pregnant in cm, plus or minus 2.

When does it start to be used?

After about 20 weeks.

Can I measure it myself?

Not accurately.

What if it is too small?

You may be offered a growth scan.

Does it work with twins?

No, it runs larger.

Sources

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Effortless Math Team

4 minutes ago