Flat Sheet vs Fitted Sheet: Do You Need Both?

Unfold a new bedding set and you will find two large flat pieces of fabric that look almost identical. One is your flat sheet, the other your fitted sheet, and they do very different jobs. Whether you actually need both comes down to how you like to sleep. Here is a maker's guide to the difference, with a few notes for anyone shopping for linen sheets in Australia.

What is a fitted sheet?

A fitted sheet is the one with elastic sewn into its corners. It stretches over your mattress and stays put, giving you the smooth surface you actually lie on. Fit is everything: a fitted sheet has to match your mattress depth as well as its length and width, or it will pop off in the night. If you are unsure of your size, our guide to linen sheet sizes in Australia walks through every dimension, including deep mattresses.

What is a flat sheet?

A flat sheet is a simple rectangle with no elastic. It sits between you and your duvet or blanket as a breathable top layer you can tuck in or leave loose. In summer it can be your only cover; in an Australian winter it becomes an extra insulating layer that traps warm air without the weight of another blanket. A flat sheet also protects your duvet cover, so you wash the lighter sheet more often and the cover far less. You can shop individual French linen flat sheets on their own or as part of a set.

Flat sheet vs fitted sheet: the key differences

The simplest way to remember it: the fitted sheet dresses your mattress, and the flat sheet dresses you. One has elastic corners and a fixed shape; the other is a plain rectangle you arrange however you like. A fitted sheet is essential on every bed. A flat sheet is optional, but a very good option, especially in cooler months. The weave matters too, since a heavier, more breathable fabric behaves differently across seasons than a thin one.

Do you actually need both?

You always need a fitted sheet. Whether you add a flat sheet depends on your climate and habits. In winter a linen flat sheet earns its place, because linen is breathable yet insulating, keeping you warm without the clammy overheating of synthetic layers. For hot sleepers, a flat sheet on its own is often enough cover. If you use a duvet, a flat sheet underneath keeps the cover fresh between washes. Prefer to buy everything together? Our French linen sheet sets pair a fitted and flat sheet with matching pillowcases, and you can also browse all French linen bed sheets individually.

Why linen makes the difference

Linen's open weave regulates temperature better than cotton or microfibre, which is why it works right through the year. Ours is stonewashed 100% French flax at 165 to 175 GSM, substantial enough to feel cosy in winter and breathable enough for summer, and it is OEKO-TEX certified for skin safety. If you are weighing up fabric weight, our note on what GSM linen sheets should be explains why 165 to 175 is the comfortable middle ground. Every piece is made to order in AU, US, UK and EU sizes, plus custom sizing, and ships to Australia and New Zealand.

Frequently asked questions

Can you use a flat sheet as a fitted sheet?
Not really. A flat sheet has no elastic, so it will not grip the mattress and will slide off as you move. You can tuck it in tightly in a pinch, but a proper fitted sheet stays put all night.

Do linen sheet sets include a flat sheet?
Ours do. A SCANDALINEN sheet set includes a fitted sheet, a flat sheet and pillowcases, all in matching stonewashed French linen. You can also buy any piece on its own.

Is a linen flat sheet warm enough for winter?
On its own it is a light layer, but under a duvet or quilt a linen flat sheet adds real insulation by trapping warm air, while still letting your skin breathe.

What size flat sheet do I need?
Match it to your bed size, and size up if you like a generous tuck. Our sizing guide covers every Australian bed dimension, plus custom options for unusual mattresses.