Fitted sheet and flat sheet sizes
A fitted sheet is sold by the mattress size it fits. Getting the depth right is what stops it pinging off.
Checked against UK retailer and maker guides on 21 October 2026.
| Bed | Fitted sheet | Flat sheet (Which?) |
|---|---|---|
| Single | 90 × 190 cm | 180 × 260 cm |
| Small double | 120 × 190 cm | – |
| Double | 135 × 190 cm | 230 × 260 cm |
| King | 150 × 200 cm | 275 × 275 cm |
| Super king | 180 × 200 cm | 300 × 265 cm |
Flat sheet sizes vary more between brands than fitted sheets, so check the label if you tuck in deeply.
How deep should a fitted sheet be?
Dunelm sells fitted sheets in depths from 25 to 38 cm and recommends one slightly deeper than your mattress. Too shallow puts strain on the fabric; too baggy and it can come off in the night.
- Measure the mattress depth at the edge, from the bottom seam to the top.
- If you use a topper, measure the mattress and topper together.
- Choose the sheet depth that is the same or just deeper than that total.
Fitted valance sheets
A fitted valance sheet goes on top of the mattress and hangs down over the base (Dunelm). Buy it by mattress size and check the drop covers your divan.
European sizes
A 140 × 200 or 160 × 200 cm mattress needs sheets in that exact size. UK double and king sheets are too short or too narrow. See IKEA bed sizes.
Questions
What size is a double fitted sheet?
135 × 190 cm, the same as a UK double mattress. Choose a depth slightly deeper than the mattress.
What depth fitted sheet do I need?
Slightly deeper than your mattress, plus any topper. Dunelm sells depths from 25 to 38 cm.
Where these numbers come from
Checked 21 October 2026. Makers round sizes differently, so always check the dimensions on the product you're buying.