How to Measure Your Bed for a Custom-Size Mattress

If your bed was built to a custom size, measuring the inside of the frame is the first step to ordering a mattress that fits. Use a tape measure, record the dimensions carefully and confirm the final measurements with the mattress manufacturer before production.

Step 1: Remove the old mattress

Clear the bedding and remove the existing mattress so you can see the space where the new one will rest.

Step 2: Measure the inside length and width of the frame

Measure between the inside edges of the frame, rather than using its outside dimensions. Record the length and width in the same unit. Include any inset or lip that affects the usable space.

Step 3: Check measurements at more than one point

Measure the length and width at both ends and near the middle. If readings differ, send all of them to DeepNap. A photo of the frame may help the team discuss an unusual shape.

Step 4: Choose the mattress thickness

Consider the height of the side rails and headboard, your preferred bed height and the available thicknesses for your chosen model. Thickness can affect how a mattress sits in the frame.

Step 5: Submit dimensions for confirmation

Enter your measurements in the Custom Size Builder. DeepNap will confirm the production dimensions, model and quote with you before making the mattress. Do not subtract a fixed allowance from your measurements unless the team confirms it for your frame.