Fundal Height Calculator: SFH by Week, Fetal Weight Estimate

Your details

Complete weeks of pregnancy as confirmed by your dating scan.
weeks
Additional days beyond the complete weeks (0-6).
days
Measured from the top of the pubic symphysis to the top of the fundus with a non-elastic tape, in a straight line.
cm
Needed for Johnson's fetal weight estimate. Select Yes if your pre-pregnancy or current weight exceeds 91 kg (200 lb).
Used in Johnson's formula: subtract 12 when the vertex is at or above the level of the ischial spines, and 11 when it has descended below them. Applies only after about 34 weeks.
SFH ratioAppropriate for dates
0.98

Your SFH divided by gestational age in weeks; 1.0 is ideal

Fundal height (cm)27.5cm
Expected SFH (median)27.7cm
Difference from median-0.2cm
AssessmentAppropriate for gestational age
10th percentile25.5
90th percentile29.9
GA (decimal weeks)28
0.98
Well below expected<0.85Below expected0.85-0.93Normal range0.93-1.07Above expected1.07-1.15Well above expected1.15+

SFH 27.5 cm at 28 weeks: Appropriate for gestational age.

  • Your SFH of 27.5 cm at 28 weeks is 0.2 cm below the median for this gestational age.
  • The SFH ratio (SFH divided by gestational weeks) is 0.98, very close to 1.0 (ideal).
  • Fetal weight estimation with Johnson's formula is most reliable from 33 weeks onward. It is not shown for 28 weeks.
  • A single measurement is a screening tool only. Consistently small or large readings over multiple visits, or any concern, should be evaluated with ultrasound.

Next stepYour measurement falls within the expected range. Continue attending routine antenatal appointments and report any concerns to your midwife or doctor.

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