Box Cushion Calculator & Mixed Fabric Plan
Plan finished box cushion covers of different sizes on one fabric. Get cut pieces, zipper halves, a layout and an existing-cut check.
From finished cover to cutting table
One fabric. Your whole cushion set.
Turn finished rectangular cover sizes into faces, boxing and zipper halves. Mix sizes, see every cut and check a piece of fabric you already have.
44 in layout + 10% extra, rounded up to 9 in increments.
7 cut pieces · 1 cushion · one fabric · a feasible layout, not a proven minimumSee every cut ↓ · Edit cover sizes
Your fabric
Finished cover sizes
Measure between the finished seam lines. These are not foam cutting sizes; decide the foam fit and padding before entering your cover dimensions. Enter decimals, such as 0.5 for ½.
1 Cushion size 1
Seams, construction & piping
Up to 5 sizes and 100 cut pieces. All sizes share this fabric and grain setting.
Your cutting plan
Seat · finished cover
Illustrative shape, not to scale. Dashed back edge: centred zipper.
Separate walls join at the corners. Each zipper half includes 0.5625 in for the centre fold/seam.
Piece numbers identify individual cuts. ↓ keeps the grain; ↔ marks a quarter turn. Select a piece below for its exact position.
Seat · Top & bottom · piece 1. Cut 19 in across × 25 in down. Position: 0 in from left, 0 in from top. Piece grain runs down the roll.
| Cushion / part | Cut width × length | Count |
|---|---|---|
| 1 Seat · Top & bottom | 19 in × 25 in | 2 |
| 1 Seat · Front / back wall | 5 in × 19 in | 1 |
| 1 Seat · Side walls | 5 in × 25 in | 2 |
| 1 Seat · Back zipper halves | 3.0625 in × 19 in | 2 |
How these cuts become a cover
Every face adds two outer seam allowances to the finished width and length. Separate boxing walls add two allowances to each finished edge and to the height. Continuous boxing uses the finished perimeter plus one joining seam; with a back zipper it wraps only the front and sides. Long strips stay whole: the tool does not silently add extra joins.
The back zipper spans the finished width. Each of its two halves has the same cut length as that back edge. Combined cut height = boxing cut height + the full zipper tape width. Baste the centre seam at half the tape width, press it open, centre and stitch the zipper, then remove the basting. Check this centred-zipper construction against your actual zipper. Rounded zipper half widths may add at most 0.5 micrometre per half.
The fabric layout uses prepared usable width in a single layer. The cut table gives width across the roll and length along the grain. Allowed quarter turns are marked on the diagram; no pieces are flipped. Grain permission does not match printed motifs or account for stretch, washing shrinkage, defects or cutting gaps. Plan those separately. Pre-made piping is trim to buy; self-fabric piping strips are not included in this fabric quantity.
Buy mode adds a length reserve and rounds up to the supplier increment. Existing-cut mode uses the entered rectangle without adding purchase reserve. The search tries different rectangle orders and placements; its shortest found complete plan is feasible, not proven optimal. If it fails, another hand layout may work. Pieces that are too wide in every permitted orientation are identified separately.
For a one-cushion example, 44 in of fabric × 1.10 = 48.4 in, rounded up to 54 in in 9-in increments: 1.5 yd. The mixed example uses two 24 × 18 × 4 in seats and one 24 × 12 × 3 in back, all with 0.5 in seams and 1.125 in tape width; turns allowed. The plan uses about 72.125 in, and buys 81 in (2.25 yd) with 10% reserve. These are illustrative complete inputs, not fit recommendations.
Construction references: OnlineFabricStore box cushion guide, pp 2–3 and Sailrite boxing and zipper-plaque guidance. This worksheet is a cutting reference, not an actual-size sewing pattern. Already have your own pattern pieces? Use the fabric yardage & cut layout calculator.
