Fitted Crib Sheet Tutorial (irregular mattress size used for this tutorial)

My very first sewing project ever was making a fitted crib sheet for Jill just before she was born.  Another stay at home mom had learned how to do it and offered to come show me the steps.  It turned out to be incredibly easy and the results were beautiful.  For a standard sized crib mattress all you need to do is buy 2 yards of fabric, cut 8" squares out of the corners, sew those raw edges together to form boxed corners, and then iron all of your edges over twice to make the casing for elastic, thread 60" of narrow elastic through the casing and sew up the ends.

I made several sets of these sheets for both Jill and my nephew.  My sister particularly liked having some flannel sheets for the winter because they were a little softer and warmer.  Now I have a new nephew on the way.  My sister wants to leave her first born son in his crib for now so she bought a mini crib for the new baby.  The mini crib will fit nicely next to her bed for now and then the new baby can move up to the large crib once it's no longer being used.  It's the perfect set up- except that it has been incredibly difficult for her to find any crib sheets that fit the mini crib mattress.

Since I already know how to make standard sized crib sheets she asked if I could make crib sheets for this smaller mattress, and in truth it only requires a little bit of math to make it all work on a smaller scale.  So I'll go through everything step by step and in the end you should be able to make fitted sheets for any crib mattress that you want.

You will need: The Mattress you are making crib sheets for; a measuring tape to get the dimensions of your mattress and to measure out your fabric; the fabric that you want to use to make your crib sheet is very important of course, thin elastic to create the "fitted" part of your sheet; two safety pins for threading your elastic into the sheet; scissors to do your cutting; an iron and board create your elastic casing; and lastly you might want to use some straight pins.  If you have them available the cutting job is made even easier with a rotary cutter, a clear ruler and a cutting mat.

First you will want to take the measurements of your mattress, whatever it may be.  In this particular case my mattress was 37" long; 24" wide; and 6" high (or thick).  Here is where some math comes into play.  Double whatever the height of your mattress is and add it to both the length and the width.  So for my mattress I do:

6"H x 2 = 12"H 

37"L + 12"H = 49"L

24"W + 12"H = 36" W

You are almost done with your math, but not quite yet!  Now you want to have extra fabric to create the elastic casing and to fold over the bottom of your mattress.  So you want to add a few more inches to the length and width.  My fabric was already 43" wide so I added 7" to each dimension to get the starting size for my piece of fabric.  

49"L + 7" = 56"L

36"W + 7" = 43"W

And the final tiny piece of math you have to do will tell you the size of the squares you will cut out of each corner.  All you have to do is add your original height to half your 'extra'.  My original height was 6"H and I added 7" 'extra', so the math works out as follows.

7" / 2 = 3.5"

6"H + 3.5" = 9.5"

So now I know that I need to cut my fabric down to be 56" long and 43" wide.  Then I need to cut 9.5" squares out of each corner.  If you have a clear ruler, rotary cutter and a cutting mat I suggest you use them for cutting the squares out.  If not, then you should measure your squares out carefully and cut as straight a line as possible with your scissors.





You will end up with a shape that looks something like a funny lopsided plus sign.  You can drape this over your mattress and you will see that the center rectangle covers the top of your mattress and the flaps will drape over the sides.

Now you will need to sew the corners of your fitted sheet. Simply bring the raw edges of the squares that you just cut together with the right sides together.  you can see in the picture to the left what I mean.  You will sew these raw edges together making a box corner shape which will eventually wrap around the corners and sides of your mattress. 

The next few steps require some time with your iron and ironing board.  You will want to press all of your seam allowances open at each corner.  This will reduce the bulk of the material when you create your elastic casing and it should make it easier to thread your elastic through later. 

Next you will begin ironing a fold along all of your bottom edges.  You can choose to make this fold over whatever width you feel comfortable- just make it consistent.  To help you with your consistency you can use a hem ruler as seen in the picture to the left.  Just set your slide to the width you want and fold your fabric over the bottom of the ruler, lining up the edge of the fabric with the slide.  If you do not have a hem ruler you might like to try another method that I have found works beautifully.

Using a thin piece of cardboard you can mark a line parallel to the edge of the cardboard and use that as a guide.  This method may even work better than a hemming ruler because you can make the cardboard as long as you'd like and guide larger sections of material to the correct width.  Whichever method you use just take your time and work all the way around the sheet, moving carefully around each corner.  

Once you have made your way around the sheet once you will need to fold over all of the edges again.   This will ensure that your raw edges are not exposed to fraying and it will create a beautiful and tidy casing to thread your elastic through.  I like to fold over the second time to a slightly larger width so that the fabric doesn't push against itself.  

Once you have finished all of this ironing you will want to place two pins along your folds a few inches apart.  You will begin sewing at the bottom pin (or in this case the pink pin), and you will STOP sewing at the purple pin.

Use a straight stitch and sew along the inner part of your folds/casing.  You can see in this picture that I have the left side of my presser foot lined up to the left side of my folds/casing.  This will leave space to the right of my presser foot for the elastic to run.  Keep your stitching straight and go all the way around until you get to your 'ending' pin.  It is important that you make sure that you always have that space to the right of your needle.  You don't want to block off the channel that your elastic will run through or you'll be working with a seam ripper- which is never a pleasant experience in my opinion.  

Once you have gotten back around to your 'ending' pin you will be left with an un-sewn opening a few inches wide.  Now it is time to thread your elastic through.  Your elastic should be as long as one length and one width of the mattress.  In other words you should cut your elastic so that it wraps around one half of your mattress when un-stretched.  

49"L + 36W" = 85"

Take one end of elastic and attach it to the crib sheet with a safety pin right next to the opening you left.  Take a second safety pin and attach it to the other end of elastic.  If you have a longer/larger safety pin it should be attached to the free side of elastic.  You will be pushing this safety pin through the casing you created so the longer the safety pin is the easier your work will be.  

Once you have threaded your elastic all the way through you will need to tie or sew the ends of elastic together.  If you are using incredibly narrow elastic it will be easier to tie but if your elastic is wide enough sewing the ends together is less bulky.  

Now all you have to do is push that elastic into your channel and sew off those last few inches of  casing.  Your sheet is done!  Just slip it over the mattress and your little one is ready for sleep.