How to use BabySize

1. Enter your measurements

Open the illustration tool and enter your week of pregnancy, BPD (biparietal diameter), HC (head circumference), FL (femur length) and AC (abdominal circumference). Use millimeters (mm), checking your report for the units. Our measurement guide explains each term.

Select “Create illustration” to see the result. After editing any value, select it again to update the image. If a measurement is missing, check your report rather than guessing or substituting another value.

2. Check the on-screen scale

Select “Calibrate screen,” measure the reference line with a ruler and enter its length in millimeters. Choose “Apply calibration,” then “Actual size (100%).”

Check the illustration's scale bar with your ruler. Recalibrate if you change screens or browser zoom. “Fit to screen” is useful for viewing the whole illustration, but usually won't show it at actual size. See the screen calibration guide for more detail.

3. Download your image

Choose whether to include the measurement labels using “Show measurements.” The scale bar is always included. Select “Download image” to save a PNG to your device's downloads.

Screen calibration doesn't carry over to the file. When viewing it on another device or printing it, check the scale bar with a ruler.

4. Save measurements for later

You can create and download an illustration without an account. To revisit the measurements later, sign in, give the record a name, check the consent box and select “Save measurements.” Open or delete records in Saved measurements.

Saved measurements are redrawn using the current version of the tool, so the illustration may change as the tool improves. Download a copy as well if you want to keep today's image. Read more about downloads and saved measurements, or see our Privacy Policy for how we handle data.

5. Make a paper keepsake

Keep the calibrated 100% view and follow the tracing guide. Lightly trace the outline onto paper, then cut it out. Add the date, your week of pregnancy and a note to your baby on the back.

The outline is a size illustration and a keepsake. For its limitations and our content sources, see About BabySize.