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If you’ve been quilting for more than 5 minutes, you’ve probably made a HST (Half Square Triangle unit) a time or two (or hundred or thousand.) There are actually several ways to make them, but today I thought I’d show you the most common way to do it. Just in case you’re not sure what I’m referring to, a HST looks like this, and we tend to use them A LOT in quilting:

Each square is cut in half into 2 triangles, and then sewn back together to form a square.

I really like to make my units a little big and then trim them down to the perfect size- I find that no matter how careful I am with cutting, pinning, and sewing, my units can end up a little wonky. (Some people use starch to make their units behave… which is a fine solution… I just don’t like to have to clean my iron.)

I’ve made up a PDF “Cheat Sheet” for you- it’s basically a guide so you can tell at a glance what size to cut your squares for making HSTs. PLEASE NOTE- I NOTICED AN ERROR IN MY ORIGINAL CHART- PLEASE MAKE SURE YOU HAVE THE ONE THAT SAYS “REVISED.” THANKS!

Let’s go over how to use the chart!

You can choose whether you want to make the HST the exact size you want it to be, or if you want to make it a little big so you can trim it down.

Look on the left side of the chart- the 2 yellow columns will show you the size of the HST when it’s done (I’ve given you measurements with and without seam allowance, because I know sometimes my brain doesn’t want to do that extra little bit of math, and I figure that some of you are the same way, LOL.) So let’s say you need your HST’s to be 5″ in your quilt- that means you need them to be 5 1/2″ with the seam allowance. Find that measurement in the chart:

Then just look to the right, and choose the measurement in the first white column if you are making them to the exact size. Choose the measurement in the second white column if you are making them larger for trimming. This is the measurement that you will cut the squares.

If you need an unusually sized HST (5 3/8″?? 3 7/8″???), I’ve also included the FORMULA at the bottom of the chart for calculating what size squares to cut. (Sorry- you WILL have to do the math for this) I’ve included the formulas both for making the HSTs to the exact size needed and for making them a little big for trimming:

Now, let’s make some HSTs using the chart! Remember that however many squares you cut, that is now many HSTs you will end up with. So, if you cut 2 squares and sew them up according to this method, you will end up with 2 identical HSTs. If you cut 50 squares and assemble them according to this method, you will end up with 50 HSTs.

As I mentioned, I like to make mine a little big and trim them, so that’s how I’m going to make mine. Using the example above, I want my HSTs to be 5 1/2″ (so that their finished size in my quilt is 5″.) So, I’m going to cut 2 squares which are 6 1/8″.

On the WRONG side of the fabric, I will draw my line down the center diagonally, which will be my cutting line. Then I draw a line 1/4″ from the center line- these will be my sewing lines. (You can skip drawing those sewing lines if you want, and rely on your 1/4″ mark/guide on your machine. But I like having the lines there to insure accuracy.) I found this nifty little ruler which makes it really easy to draw your lines.

Pin 2 squares RIGHT SIDES TOGETHER. I will sew on the side lines, and then cut the center line:

I open them up and press- depending on the pattern, sometimes I press the seam open, and sometimes I press it to the darker fabric.

Now, if you chosen to make them to the exact size, you would just trim off those “dog ears,” and you’re done.

But since I’ve made mine a little big, the measurements in the chart have resulted in HSTs which are about 5 3/4″, so I’ll trim them to my desired 5 1/2″. A note about trimming the HSTs- be sure to use the 45 degree line on your cutting mat, or on your ruler. This will assure that you have PERFECT HSTs:

Now I have 2 pretty HSTs.

That’s it! Click here for a downloadable PDF of the cheat sheet, then print it out and put it next to your cutting table for easy reference!

Love all your designs and easy instructions! Thank you!

This is a great chart! You have no idea how much it has helped. Thanks so very much!

Thank you for going the extra mile for us. So glad I found you ❣

Enjoy your class

Thankyou so very much for allyour encouragement it is REALLY APPRECIATED have a wonderful day or evening Rotha ???

This was great. Thank you for the PDF

Thank you so much! our cheating sheet works so great.

Thank you so much. I have been cutting HST’s for the past two weeks and my brain is tired from trying to figure out how big I need to cut the squares. You have saved me a lot of time and trouble. I really appreciate this.

many thanks downloaded and will be printed later today

This is great! Thanks so much

this is wonderful. thanks. but my computer/printer says that this document can not be printed. something about a drawing error.

Hi Lori- do you have the latest version of Adobe? I’ve tested it here and it prints ok for me.

Thank you so much for this. I’m measuring challenged and this helps a lot!

I couldn’t print it from this page either, however, I was able to copy the image so I just opened a new email to me and pasted it then I was able to print it from there. Hope this helps you out if you still couldn’t get it to print.

Of course, somehow on the first go round, I totally missed the link for the cheat sheet and that worked for me as well.

I am unable to print this sheet, here or on your craftsy page>>>

Hi Adela- I’ve tested it here a couple of times and it downloads and prints OK for me. I re-uploaded the file to see if that helps. Please make sure that you have the most recent version of Adobe and try again.

Besides having the latest Adobe software, you might try printing just after you restart your computer. I don’t know all the details behind why restarting the computer works, but it does for me.

Is there a tutorial that shows using the half square triangle templet?

Thanks for the cheat sheet Jacqueline. I always use this method for HSTs using that nifty ruler to mark the lines but have never thought of making the squares larger then cutting down to size until I made the HSTs for Block One in ‘Maggies First Dance’ . My squares have turned out perfect!

I could not get this to print. Wonder if I am the only one who can’t print it off? My adobe is up to date.

Help please.

If you have not restarted your computer recently that might be why you cannot print the HST chart.

Thanks very much, a really useful chart to have by you.

I will look forward to your posts!

Thank you so much for this cheat sheet.

Oh! The ruler! It looks like Fons&Porter? Not sure. Do you remember the name of the ruler and where to purchase?

Yes it is Fons and Porter- I bought in online somewhere. http://www.shopfonsandporter.com/product/Fons-and-Porter-Quarter-Inch-Seam-Marker/fabric-and-notions-rulers-and-templates

Joann Fabrics as well as quilt shops also carry this item.

Hello, I just came across this and it appears to be so helpful. The only problem is I can’t read it very well when I print it out. I was wondering if you could put it in a PDF file for downloading. Maybe that’s already out there & I just haven’t come across it.

Thanks,

Barbara English (Benglish46@gmx.com)

Thanks for the cheat sheet – thinking of you and your family x

Thank you for the sheet and tutorial.

Your explanations are so easy to follow and are very educational. You make it so easy to understand that I can’t fail when making HST’s now. Thanks.

This chart came at the perfect time for me because of the project I am starting today. Thank you. Often I think of the words at the bottom of this page. It has made quite a difference (all good) in my life. May Peace be with you.

Thank you Jacqueline – this chart is wonderful! Our prayers are with you and your family.

Oh thank you for this! This will come in real handy!

Thanks so much for cheat sheet, downloaded,printed,and posted by cutting table.Prayers and thoughts for you and your family.

My prayers will include you and your family! Thank you for the HST. Will definitely use that method from now on.

Thank you for the HST cheat sheet. I need to print and post somewhere that I won’t forget I have it!

Thank you for the HST tutorial. Thoughts and prayers are with you and your family.

Thank you for this cheat sheet. It will be very helpful.

Thank you so much for this tutorial so handy. Thoughts are with you and your family at this time.

Stitch therapy and friend therapy! Sending you hugs and prayers.

Thank you so much for the HST sheets and charts! These will be so useful.

Thanks for this chart, it will be very handy.

Thank you for your wonderful instructions & cheat sheet. It makes everything so much easier.

Is there a sheet for Quarter Square triangles?

Thank you soooo much for the cheet sheet. Have printed and laminated the sheet. Thanks for the work put into working out the formulas. Makes my life easier when making quilts. Love your site/blog.

Question might be silly: 1/4 inch seam marked on the HST should they be scant 1/4 inch or full 1/4 inch?

Thank you for doing this revision. I have it printed out and will replace the previous one. I love your creativity and your projects!

THANKS FOR THE HST CHEAT SHEET….DEFINITELY NEEDED IF QUILTING. ALL YOUR IDEAS ARE VERY HELPFUL.

This is super helpful! I am trying to make a modern sampler quilt and am re-sizing blocks and you just saved me hours of math! Very much appreciated.

Thank you Jacquelynne for the information. Really appreciate it. Looking forward to the start of the new quilt.

Will the chart print from an iPad?

Thanks!

I found the download link under the last photo! Thanks!

Thank you! thank you! thank you! I just spent a few hours trying to get the right measurements and it was right here all the time. bless you

Thank you. Great help.

Thank you, thank you! Finally a HST chart that makes sense! I am doing more of these fun squares but when I am designing a pattern that includes them it makes my head hurt trying to figure out what is the right size. I’m designing a “round” table cloth right now using the Missouri Star block and was beating my head on the table trying to get the right size HST square. Thank you so much. I know other quilters appreciate your chart as much as I do.

Thank you for this wonderful chart. I appreciate this so much, you have made things so much easier for me. Thank you.

Thank you so much. I have been looking for something that would give me some guidance on how much fabric to purchase and how large/small to make the triangles to achieve the finished results. This has been most helpful.

Thanks! Great tutorial

Thank you so much. I’m getting ready to make my son’s wedding quilt and this eliminates all my guess work.

Thank you for this! Very handy. :)

This measurement chart is fabulous, thanks, will save me lots of time

Thank you for this tutorial. I love your site.

Could you put a better copy of the cheat sheet on your webpage? It’s very blurry and hard to read…it’s missing some parts of the numbers.

Did you download the PDF version of the cheat sheet? The PDF is perfectly clear to see. Thanks!

Thanks for sharing

I’ve already started my starburst quilt and have 2 squares complete, so making the triangle bigger is not an option for me. Is there another solution of adding more HST to the side and top to make it a twin size, I dont want a lopsided starburst. Can you help me with this dilemma?

Thank you so much! Math and I struggle to get along, this chat was wonderful and made it very easy for me to figure out what sizes I needed.

The print on the ‘cheat sheet’ above isn’t clear, but I thought it would print out OK, but it didn’t. Some of the numbers can’t be read. Can you send this chart again?

Thanks so much for the cheat sheet and everything you do. I love the Silver Linings blocks. I do a tremendous amount of gardening every year and am hoping to start these blocks this week.

Thank you for this cheat sheet! I am fairly new to quilting and am creating my first design.

Although there are a lot of how-to tutorials out there for HST’s this is the first site that lets me determine how large my fabric needs to be. You have saved me a lot of time (and probably fabric) with this chart. Thanks again!

Thanks for the trimming clarification. I struggled and got one the right size but totally wonky! After I thought it through I used the diagonal. Another point: don’t trim all on one or two sides. You have to find the center and measure on all sides.

Please put the comments everyone makes on a separate page- if I hadn’t taken the time to scroll through them ALL I would have missed the good stuff at the bottom. It would also be nice if you could PDF your wonderful chart so it could be printed for reference more easily! Thanks

Oops , sorry- just found the pdf print link! Thanks!

If I used the half size triangle chart and the come out to 5 inch what size do I cut my regular square so it will all fit? Do I cut my regular square 5 inches so all my blocks will be 4 1/2 inch?

Thank you for the HST cheat Sheet as a novice beginning quilter, this is the hardest thing for me to figure out as the Silver Linings Sew Along has ‘us’ making squares larger then trim to a specific size. So maybe I’ll try making to size and see if its easier once all are sewn together. Fingers crossed.

Printed the chart and will have it on my bulletin board in my sewing room so I won’t have to hunt for it. Love love the chart!!!

THANK YOU!! You are so thoughtful to share this info. I am a new quilter and struggling with how much to add. People say around 1″ and now I have a consistent chart

Thank you for your cheat sheet and clear instructions. I’ve made as many as 2000 HST for a single quilt so I feel your pain!

I highly recommend the “Bloc Loc “ ruler and a small rotating cutting board for perfect trimming. It has a groove which “locks” into the seam of pressed blocks and lines up the corners perfectly for trimming, 2 sides at a time. Rotate, slide the ruler to the other side and trim the other 2 sides.

Hi Jacquelynne

I have sewed 80 HST and wondered what method would be the best to trim them to 4.5 inches. You suggested the 45 degree lines. Thank you so much for the advise.

Regards

Dalene

Thank You SO VERY MUCH for your chart and thte directions. I am working on a quilt and trying to figure out block sizes.

Your directions and PDF are exactly what I need !!!!!!!!!!!

Thank you thank you for your heart to teach others using your gifts!

Thank you so much!

Thank you for the chart. I will find this very helpful.

thank you for pdf. yes, 5 minutes, just finished learning Flying Geese. This is my little note about HST: “The only thing you needed to know was the math of what size square to cut – finished size plus 7/8″

(2 seams x 0.25 + 0.25 slop seam x 1.414 = 0.50 + 0.3535 = 0.8535 ~=0.875 ~= 7/8″).

for example: finished 3″ => 3″ + 7/8″ = 3-7/8″ a little bigger + 1/4″ = 3 + 1-1/8″ = 4-1/8”

note: a square + b square = c square, square root of 2 = 1.414