Measurement guide

How to Measure a Sofa for Custom Cushions

Custom sofa cushion sets come as 6 pieces — three seat pads and three back pads. We only need the overall width of your sofa frame; we divide it into three equal seat and back cushions for you. You need six measurements across both parts.

Two ways to measure — pick yours

This guide is for a full custom cushion set built to your sofa frame. If instead you're replacing worn foam and keeping your existing covers, measure the cover, not the frame or the old foam. Upholsterers call the cover's side panel the “boxing” — match the seam-to-seam boxing height. Old foam is often cheaply oversized and compresses fast, so it can measure thicker than the cover; go by the cover and let a Dacron wrap add the fullness (skip loose polyfill, which just shifts). Add ½" to 1" for a snug fit, and see our complete guide to couch and sofa cushion replacement for that route.

Measuring a loveseat (2-seater)? Click here

Part A — Sofa seat

Step 1 — Start here

Choose the seat cushion thickness

Select a thickness between 2 and 5 inches. Write this number down — you will need it in Step 6 to calculate the correct back cushion height.

Step 2

Measure the overall seat width

Measure the full width of the sofa's seating area from one side of the frame to the other. Provide the total — we will divide it into three equal seat pads automatically.

Measure the frame, not your old cushions

Foam compresses and fabric stretches over time. Old cushions will give you inaccurate dimensions. Always measure the bare wood or metal frame directly.

Step 3

Measure the seat depth

Measure from the front edge of the seat frame to the back rail. If the frame has a front lip or rail, measure to the inside edge.

Part B — Sofa back

Step 4

Choose the back cushion thickness

Select a thickness between 2 and 5 inches. Back cushions are often ordered 1 inch thinner than the seat for a more comfortable, relaxed posture.

Step 5

Measure the overall back width

Measure the full width of the back frame from side to side. This is usually the same as the seat width, but measure independently to confirm. We will divide it into three equal back pads.

Step 6 — Calculation required

Calculate the back cushion height

The back pads rest on top of the seat pads, so they start higher than the bottom of the back frame. If you order the full frame height, the back cushions will sit too high and push the seat pads forward. Subtract the seat thickness from the total frame height.

Back height (order) = Total frame height − Seat cushion thickness

Worked example

Your sofa back frame measures 30" tall. You chose a 5" thick seat pad in Step 1.

30" − 5" = Order 25" back cushion height.

Measuring tips

The book method

Unsure about thickness? Stack books on the seat frame until the height feels comfortable. Measure the stack to find your ideal thickness before committing.

Use a rigid tape measure

A steel retractable tape gives straight, consistent readings across long sofa spans. Avoid soft tailor's tape — it sags and causes errors.

Round to the nearest ½"

We produce cushions in ½" increments. Round each measurement to the nearest half-inch before entering dimensions at checkout.

Write Step 1 down first

The seat thickness from Step 1 is used again in Step 6. Note it before measuring the frame so you have it ready for the back height calculation.

Measuring FAQ

Do I measure the frame or the old cushions?
For a full custom set built to your sofa, measure the bare frame, since old foam compresses and old covers stretch. If you're only replacing the foam and reusing your covers, measure the cover's boxing (the seam-to-seam side height) instead, and add ½" to 1".

My old foam is thicker than my cover measurement — which do I order?
Go by the cover's boxing, not the old foam. Manufacturers often oversize cheap foam so it looks full at first, then it compresses fast, which is why the tired foam can still measure thicker than the cover. Order foam to the boxing height and let a Dacron wrap add the rounded fullness. If you can feel the springs when you sit, you can go slightly thicker or a firmer density.

How do I work out the back cushion height?
Subtract your seat cushion thickness from the total back frame height. The backs rest on top of the seats, so ordering the full frame height makes them sit too high. Example: a 30" back frame with a 5" seat pad means you order a 25" back height.

How many cushions will my sofa set have?
A standard set is six pieces: three seat pads and three back pads, divided from your overall width. If you'd rather have one, two, or a different number, see our guide to one, two, or three couch cushions.

More couch cushion guides:

Not sure about the back height calculation?

Email us at support@uscushion.com — we'll work out the numbers with you before you order.

How to Measure a Sofa for Custom Cushions measurement diagram

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