How To Convert Flat Bed Sheet into Fitted Bed Sheet

Fitted bed sheets are the type of sheets which have elastic stitched at the edges. Fitted sheets are used to fit and cover the mattress. They are also used underneath Flat bed sheet, that is why it is also known as bottom sheet.
Table of Contents
Why you Might Want to Convert Flat Bed Sheet into Fitted Bed Sheet?
Flat sheets are very common and in an average household there is abundance of flat sheets but people are usually hunting for a fitted bed sheet. Fitted sheets are normally more pricier than flat bedsheets depending on the material used and sometime fitted bed sheets are also not included in the bedding sets.
Things you Need
- A Flat Bed Sheet
- Matching Thread
- Scissors
- Good quality 3/16″ or ¼” Elastic shorter in length than the Perimeter of your mattress (Length + Width + Length + Width)
- Tape Measure
3 Steps to Convert Flat Sheet into Fitted Sheet
Luckily following simple steps (given below), you can convert your flat sheet into a comfortable fitted bed sheet.
Measure your Mattress
First measure your mattress carefully. From one corner to other, measure all the sides. You should know the exact length, width and thickness of your mattress before moving on to the next step.
Cutting the Flat Bed Sheet
Now start cutting your flat sheet to make a fitted bed sheet. The width and length of required fitted sheet are calculated using the formulas given below. Use the calculated width and length of fitted sheet to cut the flat sheet.
Width of Fitted Sheet
Width of the fitted sheet = Width of your mattress + Thickness of Mattress + Thickness of Mattress + extra 5″ for seam allowance and bottom fabric.
Length of Fitted Sheet
Length of fitted sheet = Length of your mattress + Thickness of Mattress + Thickness of Mattress + extra 5″ for seam allowance and bottom fabric.
Cut the Sheet Corners
Next step is to cut all the four corners of bed sheet in square shape. For that, fold your sheet in half by length, then fold your sheet in half by width. This will pile up all four corners at one spot.
Now cut all four corners of flat sheet together making a square shape with a measurement equal to Thickness of mattress + extra 3″. After cutting The sheet will look like this.

Sew and Stitch the Elastic and Sheet Corners
Sew the Sheet Corner
Place the sheet with wrong side facing towards you and fold it in a way that the two plus sign shown in figure below, meet together. Now Sew the sheet together from this point to the point where the square ends using a ½” seam allowance. Sew other three corners like this and then trim the extra edges.


The sheet would look like this once corners are sewn together.

Stitch the Elastic
Now place the elastic on the edge of the sheet leaving a gap of around 1 inch from the end and stitch it with sewing machine to attach it permanently. After attaching the elastic to all four sides of sheet, fold them with elastic inside and close the edges using regular straight stitch and that’s it, Your very own fitted bed sheet is ready.
Also Read difference between flat and fitted sheet.