Work out how much fabric you need for square or rectangular cushion covers. Get cut sizes for an envelope back or a simple two-piece zip cover, a row layout across your fabric and a purchase length in metres or yards.
How much fabric do I need for a cushion cover?
The answer depends on the cut pieces and how they fit across the fabric, not just the finished cushion area. An envelope cover has one front and two overlapping back pieces. A simple edge-seam zip cover has a front and a back. Seam and hem allowances make those pieces larger than the finished cover.
This calculator makes a cut list, places the pieces in straight rows across one continuous length of fabric, adds your chosen allowances and rounds up to the seller's purchase increment. It calculates all identical covers together, so spare width in a row can hold another piece.
Measure the finished cover, not the cutting rectangle
Use the finished seam-to-seam width and height you want. Decide that size from your insert, fabric and sewing pattern. A plump feather insert, a firm pad and a stretchy fabric do not necessarily need the same fit adjustment. The tool does not automatically subtract a fixed amount from every insert.
For a square cover, enter the same width and height. For a rectangular cover, its width initially runs across the fabric and its height along the roll. If your pattern has a particular top edge, mark it on every piece before cutting.
Envelope cushion cover cut-size formula
Let W be the finished cover width, H the finished height, S the seam allowance, O the total finished back overlap and F the width of each hem fold. Use the same unit for all five measurements.
- Front: cut one rectangle (W + 2S) wide and (H + 2S) high.
- Back: cut two equal rectangles, each (W + 2S) wide and ((H + O) ÷ 2 + S + 2F) high.
Each back rectangle has one outer seam allowance and one double-fold hem along its opening edge. The two folds use 2F of fabric. After hemming and the outer seam, each back panel extends (H + O) ÷ 2 across the finished cover height. Together they span H + O, leaving the intended overlap O.
The overlap is measured after the hems are sewn. Adding the whole overlap to both halves would count it twice. Likewise, adding a seam allowance at the hemmed opening as well as the two folds would not match this construction.
Love & Lilly's envelope pillow tutorial demonstrates a front with two hemmed overlapping back pieces. Its fit choices are specific to that project. Here you set the finished cover size, overlap and folds explicitly.
Two-piece zip cover formula
Cut two rectangles, each (W + 2S) wide and (H + 2S) high. This assumes a zipper sewn into one edge seam using the selected allowance. Follow your zipper method for placement, length and finishing.
The fabric estimate does not include separate zipper strips, a boxed side band, piping, lining, tabs or a decorative flange. If your pattern calls for any of these, add their pieces in a separate material plan. This tool is for flat throw-pillow covers, not thick seat cushions with side panels.
Worked example: two 45 × 45 cm envelope covers
Choose a finished size of 45 × 45 cm, a seam allowance of 1.5 cm, a finished overlap of 15 cm and two hem folds of 1.5 cm each.
- Each front is 45 + 3 = 48 cm wide and 48 cm high.
- Each back is 48 cm wide and (45 + 15) ÷ 2 + 1.5 + 3 = 34.5 cm high.
- For two covers, cut two fronts and four backs.
- At 140 cm usable width, two 48 cm pieces fit across each row.
- Keeping the original direction uses one 48 cm row and two 34.5 cm rows, totalling 117 cm.
- Add 5 cm total at the ends, then 10% reserve: (117 + 5) × 1.10 = 134.2 cm.
- With no shrinkage and a 0.1 m purchase increment, order 1.4 m.
- At an illustrative €12 per metre, the fabric cost is €16.80.
The example button fills these values. They are planning assumptions, not a universal sewing pattern or current fabric price. If the fabric permits a 90° turn, the alternative row plan can be shorter. The calculator shows both tested lengths and the selected arrangement.
Fabric width, selvedges and direction
Use the width you can actually cut, after excluding selvedges and unusable edges. A label saying 140 cm does not prove that all 140 cm are available for the pattern pieces. Measure or check the product specification.
The default keeps the cover height along the roll. The optional comparison turns every piece by 90°, then builds another row plan. It chooses the shorter valid result from those two plans. It does not rotate individual pieces in different directions or claim to find the mathematically shortest possible arrangement.
Keep the intended grain and nap direction for every front and back. Turning fabric can change the direction of a print or how its surface reflects light. A shorter layout is only useful when the fabric and design allow it.
Allowing for shrinkage
The width available for cutting is usable width × (1 − width shrinkage ÷ 100). This can change how many pieces fit across a row, so width shrinkage is checked before calculating length.
After adding end allowance and reserve, the pre-shrink purchase length is required cutting length ÷ (1 − length shrinkage ÷ 100). For example, retaining 1.4 m after a measured 5% length shrinkage requires 1.4 ÷ 0.95 = 1.474 m before purchase rounding. Multiplying by 1.05 would give a slightly smaller amount.
Use the fabric's instructions or your own suitable sample test to choose these percentages. Do not assume every fabric shrinks by the same amount. If the fabric is already prepared and its usable width is measured afterwards, leave shrinkage at zero to avoid counting it again.
Pattern repeats need a separate layout
Plain rectangles can fit on a roll while their motifs fail to line up. Stripes, checks, centred designs and repeats in two directions need attention to the position of each piece. A general extra percentage does not guarantee enough material for that arrangement.
Sailrite's pattern-matching guide demonstrates checking both horizontal and vertical repeats and positioning the individual pieces. This calculator does not perform that matching. Use the cut list as a starting point, then make a separate pattern-aware layout before ordering patterned fabric.
Common questions
Why not divide the total piece area by the fabric width?
That gives an area-based lower bound, not a cuttable length. Whole rectangles may leave unused strips beside each row. The row plan respects the usable width and retains those gaps. Pieces are not joined from small offcuts.
Is the overlap added to both back pieces?
The finished total overlap is shared between two equal backs. Each finished back extends half of the cover height plus half of the overlap. Its cut height then receives one seam allowance and two hem folds.
Can I enter inches and buy in yards?
Yes. Measurement and purchase units are separate. Enter decimal inches or feet, and choose metres or yards for ordering. Changing the measurement unit converts the entered dimensions. Changing the purchase unit converts the price per unit and resets the purchase increment to 0.1 m or 0.25 yd, which you should check against the seller's rules.
Does the result include zippers, inserts or piping?
No. It covers the listed fabric rectangles. Buy the insert and any zipper, thread, piping cord or extra fabric components separately using your sewing pattern. The price result includes only the fabric length at the entered unit price.
Can I combine several remnants?
The displayed order is one continuous length at the entered usable width. Do not add remnant lengths together and assume they reproduce this layout. Check which complete pieces fit on each remnant, preserving the intended direction.
What should I check before cutting?
Confirm the finished fit, seam allowance and opening method. Mark the fronts and backs on paper or a test fabric, check the hem folds and finished overlap, then verify the grain direction and usable roll width. The row schedule gives every row; for large batches the drawing shows only the first eight rows.
Which calculators help finish the room?
Plan matching window textiles with the curtain fabric calculator, wall colour with the paint calculator, or wall panel quantities with the acoustic panel coverage calculator. The acoustic tool calculates physical panel coverage, not a predicted sound reduction.
