Quick answer

Measure your mattress first: a crib sheet (40x90cm) fits newborn cribs, a cot sheet (120x60cm) fits standard cots, and a cot bed sheet (140x70cm) fits toddler cot beds. Choose 100% cotton jersey for softness and breathability.

Why mattress size is the only rule

Crib and cot sheets are not interchangeable. A crib sheet (40x90cm) is too small for a standard cot mattress (120x60cm), and a cot sheet will be loose and unsafe on a crib. Always check the mattress dimensions before buying.

The three common sizes are: crib (40x90cm), standard cot (120x60cm), and cot bed (140x70cm). Cot beds are longer to grow with your toddler, so the sheet size changes accordingly.

Cotton jersey fabric benefits

100% cotton jersey is stretchy, soft, and breathable — ideal for a baby's sensitive skin. The stretch helps the sheet fit snugly around the mattress corners without wrinkling. Jersey also washes well and stays soft over time.

Step-by-step guide to choose a cotton fitted sheet for crib or cot

  1. Measure your mattress length and width: Use a tape measure to get the exact length and width of your mattress. Crib mattresses are typically 40x90cm, standard cot mattresses 120x60cm, and cot bed mattresses 140x70cm. Write the numbers down. A common mistake is guessing the size. Always measure — even if you think you know the model.
  2. Match the sheet size to your mattress: Select a fitted sheet that matches your mattress dimensions exactly. For a 40x90cm crib, choose a crib sheet. For a 120x60cm cot, pick a cot sheet. For a 140x70cm cot bed, get a cot bed sheet. Do not size up or down. A sheet that is too large can create loose fabric, which is a suffocation hazard. A sheet that is too small may pop off the corners.
  3. Choose 100% cotton jersey fabric: Look for sheets labeled 100% cotton jersey. Jersey knit stretches slightly, making it easier to fit over the mattress and stay in place. It is also breathable and gentle on baby's skin. Avoid polyester blends for fitted sheets — they trap heat and are less breathable than cotton.
  4. Check the sheet depth: Measure the thickness of your mattress. Most standard crib and cot mattresses are 10-15 cm deep. Ensure the fitted sheet has enough depth (usually 15-20 cm) to cover the mattress fully without slipping. If your mattress is thicker than average, look for deep-pocket sheets. A shallow sheet may not stay on.
  5. Buy a pack of two for convenience: Consider purchasing a pack of two fitted sheets. This gives you a clean sheet ready for middle-of-the-night changes or laundry day. Many packs, like the Cot Fitted Sheet 120x60cm Pack Of 2, offer value and practicality. Having a spare sheet saves time and reduces stress — you won't need to do laundry immediately after a spill.

Products mentioned in this guide