Fundal Height Calculator
HealthEstimate gestational age from a measured fundal height using the common cm-equals-weeks reference guideline between 20 and 36 weeks of pregnancy.
Estimated Gestational Age
28
Typical Range (Low)
26
Typical Range (High)
30
What is a Fundal Height?
The Fundal Height Calculator estimates gestational age from a measured fundal height, using the commonly cited reference guideline that fundal height in centimetres roughly equals gestational age in weeks, between about 20 and 36 weeks of pregnancy.
For a more precise gestational age calculation, see the Gestational Age Calculator.
How to use this Fundal Height calculator
- Enter the fundal height measurement in centimetres.
- Read the Estimated Gestational Age and Typical Range instantly.
- Compare against other dating methods (like ultrasound dating) discussed with your healthcare provider, since fundal height is a general reference rather than a precise measurement.
Formula & Methodology
Estimated Gestational Age (weeks) ≈ Fundal Height (cm), valid roughly between 20-36 weeks. Typical Range = Estimated Gestational Age ± 2 weeks Worked example — a fundal height of 28 cm: Estimated Gestational Age ≈ 28 weeks (typical range 26-30 weeks)
Frequently Asked Questions
Fundal height is the measured distance from the pubic bone to the top of the uterus (fundus) during pregnancy, commonly measured in centimetres at prenatal checkups from around 20 weeks onward.
A commonly cited reference guideline suggests that between roughly 20 and 36 weeks of pregnancy, fundal height in centimetres approximately equals gestational age in weeks — for example, a fundal height of 28 cm roughly corresponds to 28 weeks.
No — this is a rough reference guideline, not a precise measurement. Ultrasound dating, especially from earlier in pregnancy, is generally more accurate; fundal height is more commonly used as a general growth-tracking checkpoint at routine visits.
Individual factors like the position of the baby, amount of amniotic fluid, multiple pregnancies, maternal body size, and normal measurement variation can all cause fundal height to differ from the simple cm-equals-weeks rule of thumb.
A fundal height notably outside the typical range for gestational age is one data point a healthcare provider may use alongside other information to decide whether additional monitoring, like an ultrasound, would be helpful — this calculator doesn't provide that clinical judgment.
It's typically measured with a flexible measuring tape from the top of the pubic bone to the top of the uterus, with the patient lying down, as part of a routine prenatal checkup.
The [Gestational Age Calculator](/gestational-age-calculator/) calculates gestational age directly from days since your last menstrual period, offering a more standard dating method than the fundal height approximation used here.
No — twin and multiple pregnancies typically show a larger fundal height than the standard single-pregnancy guideline for the same gestational age, since there's more uterine content to measure.
The cm-equals-weeks reference guideline is most commonly applied between roughly 20 and 36 weeks of pregnancy; outside this range the relationship becomes less reliable.
Fundal height measurement is typically performed by a healthcare provider using consistent technique at prenatal visits; this calculator is for general educational reference rather than a substitute for professional prenatal care.
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