Almost every sofa cover that does not fit was bought on the number of seats rather than a tape measure. Sofas sold as three-seaters range from about 72 to over 100 inches wide. Five minutes with a tape saves the exchange.
The measurement that matters most
Width across the back, outer arm to outer arm. Run the tape along the back of the sofa at its widest point, which is usually the top of the arms rather than the base. Write it down.
Match that number to our fits:
- Armchair — up to about 72 inches
- Recliner sofa — around 82 inches
- Loveseat — around 94 inches
- Sofa — around 114 inches
- Oversized — around 126 inches
The other three
Depth. From the front edge of the seat to the base of the back cushion. This decides how much fabric is available to tuck into the crease, which is what holds the cover in place. Deep sofas need more tucking, not a bigger cover.
Height of the back. From the floor to the top of the back cushion. Tall-backed sofas leave less cover hanging at the rear, which is fine, but it is worth knowing before it arrives.
Arm width. Wide, rolled arms eat cover. If your arms are more than about 10 inches across at the top, take the next size up. Slim, square arms use almost none.
Where people go wrong
Measuring the cushions instead of the frame. Cushions compress and move. Measure the frame.
Measuring at the base. Many sofas are narrower at the floor than at the arms. The cover has to clear the widest point.
Rounding down. If you are between two fits, take the larger. Excess tucks away; shortfall does not.
Forgetting the throw pillows. If you keep four large cushions on the sofa, they sit on top of the cover and take up depth. That is fine, but the cover will look shorter at the front than in the photograph.
Recliners
Measure with the footrest down. The recliner fit is cut with the mechanism in mind, but you will still need to straighten the cover after the chair has been up and down a few times. Anyone who tells you otherwise has not owned a recliner.
Sectionals and chaises
Buy per section, not one long cover. Measure each section as its own sofa. In practice most L-shaped sectionals take a sofa fit on the long run and an armchair fit on the chaise, and the join sits where the sections already meet.
After it arrives
Lay it on, centre it by eye, then tuck the whole length of the seat crease firmly before you judge the fit. A cover that looks too big spread out often fits exactly right once tucked. If your seat cushions lift, put the cover down first and the cushions on top — that single step does more than the non-slip backing.
Wash cold, tumble dry low. Once it has been through the machine once it sits better than it did new, which is true of most quilted things.
Then choose the design
Once you know the fit, the choice is only about the picture. Dog designs and farm animals are the two biggest groups; wildlife and landscapes suit rooms with wood in them; celestial and dragons are for rooms that can take something graphic.
A worked example
Take an ordinary fabric three-seater. Tape across the back at the widest point, arm to arm: 108 inches. Depth from the front edge of the seat to the base of the back cushion: 24 inches. Arms are rolled and 11 inches across at the top.
The width alone points to the sofa fit at 114 inches. The rolled arms confirm it — wide arms consume cover, and the 6 inches of margin will disappear over them. If those same arms had been slim and square, the 94 inch loveseat fit would also have worked, but slightly stretched.
Now the same sofa in leather. Same fit, but buy the non-slip underlay at the same time, because friction is the thing you will be short of rather than fabric.
Between two sizes
Take the larger, every time. This is not a sales answer — a cover that is 6 inches too long tucks into the seat crease and disappears, and after one wash it settles as if it were made for the sofa. A cover 6 inches too short pulls at the arms, rides up in use, and never stops being slightly wrong.
The only exception is an armchair, where too large is visible because there is nowhere for the excess to go. On chairs, measure carefully and match closely.
Measuring for a gift
If you are buying for a sofa you cannot get a tape to, count the seat cushions and look at the arms. Two cushions with slim arms is almost always the loveseat fit; three cushions with rolled arms is the sofa fit. It is not as good as measuring, but it is right more often than guessing from a photograph.
Write the numbers down
Keep the four measurements somewhere you can find them — a note on your phone is enough. Sofa covers are the kind of thing people buy a second and third time, once for the dog and once for a change of season, and the second purchase takes thirty seconds if the numbers are already written down.