Fundal height is a simple way to check the baby’s growth at antenatal appointments. A measurement more than 2 cm off can point to a small or large baby, too much or too little amniotic fluid, or a dating error, and is usually checked with an ultrasound.
How to use the Fundal Height Calculator
- Weeks pregnant
- Measured fundal height
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter how many weeks pregnant you are and the fundal height your midwife measured.
Inputs explained
| Field | What to enter |
|---|---|
| Weeks pregnant | A number |
| Measured fundal height | In cm |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
From 24 weeks: expected fundal height (cm) ≈ gestational age in weeks
Normal range ≈ weeks ± 2 cm (± 3 cm after 36 weeks)
Worked example
Inputs — Weeks pregnant: 30; Measured fundal height: 29 cm.
Results — Expected range from = 28 cm; Expected range to = 32 cm; Difference from expected = -1 cm; Result = Within the expected range.
Key terms
- Fundal height
- Distance from the pubic bone to the top of the uterus.
Frequently asked questions
When is fundal height measured?
At each antenatal visit from about 24 weeks.
Why might fundal height be off?
Baby size, amniotic fluid, the baby's position, maternal weight or a wrong due date.
Is fundal height accurate in obesity or twins?
Less so; ultrasound is used instead.