Have you ever woken up in the middle of the night fighting with a sheet that has slipped off the mattress? The problem is usually not the bed, but not being clear about what each piece does. The fitted sheet and the flat sheet work together, but they have different roles: one holds and protects the mattress; the other separates you from the duvet with a fresh layer of cotton.
In this article, you will see clearly what each one is, how they differ and which size to choose for your bed. As at happyfriday we sell each piece separately, we also explain how to combine them so you can dress your bed exactly as you like.
what you will take away from this
- 1The fitted sheet goes over the mattress with elasticated corners; the flat sheet is plain and goes between you and the duvet.
- 2The detail most often forgotten when buying a fitted sheet is the depth of the mattress, not just the width and length.
- 3Our fitted sheets have a deep pocket for mattresses up to 32 cm; the flat sheet drops between 30 and 40 cm on each side.
- 4You have the fitted sheet and flat sheet size chart, from an 80 cm bed to a 200 cm bed.
- 5Buying by individual piece gives you total freedom to combine plains and prints your way.
the difference, in one sentence
The fitted sheet is placed directly over the mattress and has elasticated corners so it stays taut and secure. The flat sheet is a rectangular, plain piece with no elastic, placed between you and the duvet or bedspread. The first provides structure and support; the second adds softness and freshness.
One holds and protects the mattress; the other separates you from the duvet with a fresh layer of cotton.
what a fitted sheet is
It is the base of the bed. It covers the mattress and, thanks to the elasticated corners, stays firm and wrinkle-free throughout the night. As well as adding comfort, it protects the mattress from daily wear and makes weekly washing easier.
How to choose the size
Many people only measure the width and length, and forget the most important detail: the depth of the mattress. To get it right, keep these three steps in mind:
Width and length
Check the size of your bed (80, 90, 105, 135, 150, 160, 180 or 200 cm) and choose that size in the chart below.
The depth of the mattress
Our fitted sheets have a generous deep pocket that hugs mattresses up to 32 cm: more than enough for a standard mattress, and also for a higher one or one with a topper.
When in doubt
If you are between two bed sizes, choose the larger one so the elastic holds comfortably.
Made from 100% pure cotton: breathable, soft and pleasant even for sensitive skin thanks to its hypoallergenic properties. They are made in Spain with local producers and more sustainable dyeing processes, reducing water consumption and waste.
what a flat sheet is
It is the layer that sits between your body and the duvet, bedspread or duvet cover. Rectangular, plain and without elastic, it can be placed and removed with total freedom. Its great advantage is twofold: it regulates temperature and keeps the bed more hygienic.
In summer, it lets you sleep with a light layer without overheating; in winter, it adds insulation. And as it is much easier to wash than a duvet, using it means you can wash the duvet cover less often and keep the rest of your textiles clean for longer.
The turn-down, the detail that dresses the bed
The top part of the flat sheet is folded over the bedspread to form the turn-down: that fold that reveals the design and gives the bed a carefully styled, hotel-like look. That is why the flat sheet is wider and longer than the mattress: it needs enough fabric to drop between 30 and 40 cm on each side and still leave extra for the turn-down. It is also where a print stands out most, so our flat sheets are made with digital printing: intense colours and defined designs that withstand wash after wash without losing softness.
Do I need one if I use a duvet cover?
It is not essential, but it is worth it. Placed under the duvet, it lets you regulate temperature in mid-season without removing the whole duvet, and reduces how often you need to wash the cover, which is the heaviest and most awkward piece to put in the washing machine.
Like our fitted sheets, our flat sheets are made from 100% pure cotton: breathable, gentle on the skin and suitable for sensitive skin. Made in Spain, with low-impact digital printing that reduces water, energy and waste compared with traditional printing.
fitted sheet and flat sheet sizes by bed size
These are the sizes we make for both pieces. Measurements are in centimetres (width × length).
| Bed size | Fitted sheet | Flat sheet |
|---|---|---|
| Bed 80 / 90 | 90×200 | 160×270 |
| Bed 105 | 105×200 | 180×270 |
| Bed 135 / 140 | 140×200 | 210×270 |
| Bed 150 / 160 | 160×200 | 240×270 |
| Bed 180 / 200 | 180×200 · 200×200 | 260×270 |
Two notes to help you get it right:
The fitted sheet matches the width and length of your mattress; the pocket takes care of the depth. If your mattress is over 28 cm or you use a topper, that pocket is exactly what prevents the corners from popping off in the middle of the night. The flat sheet, on the other hand, is deliberately larger than the mattress so it can fall down the sides and leave enough fabric for the turn-down.
Is your mattress 190 or 200 cm long? Do not worry about that difference: thanks to the elasticated corners, our fitted sheets adapt easily to both lengths. The elastic hugs the mattress and keeps the sheet taut whichever length you have, so either option will work.
Cot or large cot? You will find specific sizes in our kids’ fitted sheets. And if you want the full chart with pillowcases, duvets and bedspreads, it is in our sheet size guide.
how to combine them your way
This is the advantage of buying individual pieces: you are not tied to a fixed set. You can choose a fitted sheet in a plain shade that matches one of the colours in your printed flat sheet, and change only one of the two whenever you fancy a refresh. It is the easiest, and most affordable, way to give the bedroom a new look without starting from scratch.
A rule that always works: a plain base and a printed flat sheet, or the other way round. Playing with that mix adds depth without overloading the room.
why choose happyfriday sheets
pure cotton, made in Spain
We design and make every piece with the 6–8 hours you spend in bed each night in mind. This is what sets us apart:
100% pure cottonbreathable and hypoallergenic
made in Spainlocal production
STANDARD 100by OEKO-TEX®
Colour that lasts: our digital printing keeps its intensity and definition wash after wash. And as we sell by individual piece, you choose only what you need and combine it as you like.
dress your bed your way
You now know what each piece does and which size you need. Choose your fitted sheet, your flat sheet and combine them however you like. Because there is a home hidden inside every house.
discover our sheets →
