Guide
How to Measure Box Dimensions from a Photo
Updated · RefScale
Quick answer
Measure a box from two straight-on photos: one of the top with a bank card lying on it (gives length and width) and one of a side with the card held flat against it (gives height). Measure the outside edges, round each number up to the next whole inch or centimeter, and write them as length × width × height.
Why you need two photos
Measuring from a photo only works for lengths in the same plane as the reference. A box has three planes that face the camera at different angles, so a single angled photo gives distorted results. Photograph one face at a time, with the reference lying on that face — this keeps the reference and the edges you measure the same distance from the camera.
Step by step
- Photograph the top. Put the box on the floor, lay a bank card flat on its top face, and photograph the top straight from above. Measure the two sides of the top: length and width.
- Photograph a side. Hold or tape the card flat against one side of the box and photograph that side straight on. Measure the vertical edge: height.
- Measure the outside. Measure the outer edges, including any bulges, flaps or tape, because carriers measure the package as shipped.
- Round up. Round each dimension up to the next whole inch or centimeter, as most carriers do, and list them as length × width × height with the longest side first.
Tips for boxes
- Close the flaps and tape the box as you will ship it before measuring.
- Use a bigger reference for big boxes. For boxes larger than about 40 cm (16 in), a sheet of A4 or US Letter paper gives a steadier scale than a card — see objects of known size.
- Mark the real corners, not the shadow or the rounded crease of the cardboard.
- Shoot from a little farther away with zoom instead of close up with the wide lens; it reduces perspective distortion on large faces.
- Double-check the heaviest shipments with a tape measure — photo measurements are estimates.
Measuring boxes with RefScale
In RefScale, pick the Credit/Debit Card preset (or your iPhone model), align it to the reference in the photo, and draw lines along the box edges. Add labels such as "L", "W" and "H" so the photo explains itself when you send it to a buyer or a courier. The general method is in how to measure an object from a photo.
Frequently asked questions
What order do box dimensions go in?
Length × width × height. Length is usually the longest side of the top, width the shorter side of the top, and height the vertical side. Carriers often simply ask for the longest side first.
Do carriers measure the inside or outside of a box?
The outside. Shipping prices are based on the external dimensions of the package as it will be shipped, including bulges.
Why do carriers round box dimensions up?
Many carriers, including UPS and FedEx, round each dimension up to the next whole inch before calculating dimensional (volumetric) weight. Rounding up yourself avoids surprise adjustments.
What is dimensional weight?
Dimensional or volumetric weight is a billing weight based on package size: length × width × height divided by a carrier-specific divisor. You pay for whichever is greater, the actual or the dimensional weight. Divisors differ by carrier, service and country, so check your carrier's current rules.
Can I measure all three dimensions from one photo?
Not reliably. In one angled photo the three sides are at different distances and angles from the camera. Measure each face straight on, with the reference lying flat on that face.