Measure the Furniture, Not the Old Cover

A loose cover is only as good as the numbers behind it. Measure the chair or sofa itself, over its existing upholstery, with the cushions in place and the furniture sitting exactly where it lives. An old cover is a poor template: years of washing, tucking and tugging will have stretched it out of shape, so anything cut to match it will be too generous in some places and mean in others. Work with a soft dressmaker's tape rather than a rigid rule, because you are measuring curves as much as straight lines.

Take every measurement three times and write down the largest figure. Ask a second pair of hands to hold the tape steady at the far end, and photograph each measurement with the tape in shot so you have a record when you are cutting weeks later. It sounds fussy; it saves fabric, time and temper.

Work Through the Furniture Piece by Piece

Break the piece down into panels and measure each one separately, rather than trying to capture the whole thing in one sweep.

• Overall width: measure across the front at the widest point, taking in the outside faces of both arms.
• Seat depth: run the tape from the front edge of the seat to the back, over the cushion, and note where the cushion is thickest.
• Back height: measure from the floor to the top of the back, then from the seat surface to the top of the back.
• Arms: record the height from floor to top of arm, the width across the front of each arm, and the depth from front to back.
• Seat drop: measure from the seat surface to the floor at the front, the sides and the back, since floors and legs are rarely level.
• Cushions: for each loose cushion, measure width, depth and thickness, and note whether it is boxed or knife-edged.

If the cover is to tuck in around the seat, add 10cm all round for the tuck-in depth. If it wraps under the frame and fastens with ties or hook-and-loop tape, add 8cm for the return.

Add Seam Allowances and Fitting Ease

Raw measurements are only the starting point. Every panel needs room to be joined and room to be manoeuvred on and off the furniture.

• Seam allowance: 2cm on each joining edge for upholstery-weight fabric, 1.5cm for lighter cottons and linens.
• Fitting ease: add 3cm to 5cm to the width and height of each main panel. Loose covers need to slide over the frame, and a cover cut exactly to size will fight you every time.
• Hem allowance: 6cm for a turned hem, 10cm if you want a deeper, weighted skirt.
• Shrinkage: if the cover will be washed, pre-shrink the fabric first and allow a further 3 to 5 per cent on top of everything else.

Write each finished panel size at the top of a fresh page: measurement plus seam allowance plus ease. These are the figures you take to the fabric shop, not the bare numbers on the furniture.

Plan for Pattern Matching

This is where most fabric budgets quietly disappear. Ask for the pattern repeat before you buy, and check whether it is a straight match or a half-drop, where every alternate length is offset by half the repeat. A half-drop repeat can demand nearly two full repeats per join.

As a working rule, allow one extra full repeat per cut panel that has to match a neighbour, plus one repeat for centring the main motif on the back and the seat. A large floral with a 64cm repeat on a three-panel back can easily add two metres to the total. On a small spot or ticking stripe, the extra is negligible, but on a big damask it is not.

Mark the direction of the fabric too. Velvet, chenille and corduroy have a pile that catches the light, so cut every panel running the same way or the cover will look patchy under a window.

Turn Your Numbers into Metres to Buy

Upholstery fabric usually comes 137cm to 140cm wide. Draw a simple cutting plan on graph paper, laying out each panel to scale and turning pieces where you can, remembering that pile and pattern direction often prevent it.

As a rough guide, a two-seat sofa with separate cushions takes around 8 to 10 metres of 140cm-wide plain fabric. Add 15 to 25 per cent where you are matching a large repeat, and another 10 per cent for velvet or a heavily patterned weave. A wing chair typically needs 5 to 6 metres plain, or 7 to 8 with matching. Round up to the nearest half metre, and buy the whole order in one go: dye lots vary, and a later top-up may not match.

Before You Cut: Checks That Save Fabric

• Lay the fabric out flat and leave it to relax for 24 hours so any folds drop out.
• Check the repeat against your panel sizes once more, marking the match points with pins along the seam lines.
• Cut the largest panels first, working from the centre of the motif outwards.
• Keep a note of your offcuts; they are useful for cushion backs, piping and repairs.

Measure twice, add generously, cut once. A cover that is a fraction too roomy can always be taken in at the seams, but fabric that has been cut too small cannot be stretched back.