Average Comforter Sizes:
- Crib 40” x 55”
- Twin 65” x 88”
- Queen 86” x 95”
- King 105” x 95”
Your quilt will shrink! Add 2”-3” more.
Size to Cut Half-Square Triangles
Add 7/8″ to your finished square size and cut in half on the diagonal once.
Size to Cut Quarter-Square Triangles
Add 1 1/4″ to your finished square size and cut in half on the diagonal twice.
Flying Gees Units
Flying Geese are twice as wide as they are tall so keep that ratio in mind. This example is a flying geese unit that finishes 3″ x 6″.
The two blue triangles are cut from one 3 7/8″ square (yielding 2 triangles – hst’s) and the grey triangle is cut from one 7 1/4″ square (yielding 4 triangles – qst’s).
Binding Formula For Straight of Grain Strips:
Perimeter +10″; then divide by 40″ for the total number of strips to cut.
Decimal conversions:
1/8 = .125 1/4 = .25 1/2 = .5 3/8 = .375 3/4 = .75 7/8 = .875
Size to Cut Triangles for On Point Quilts:
- (Finished Block size x 1.414) + 1.25 = Size to cut squares for side triangles (QST)
- (Finished Block size / 1.414) + 7/8 = Size to cut squares for corner triangles (HST)
- Round up to the nearest 1/8″.
- Side triangles are cut from 4 quarter squares.
- Corner triangles are cut from 2 half squares.
| Fin. Block Size | Side Triangles | Corner Triangles |
| 3″ | 5 1/2″ | 3″ |
| 3 1/2″ | 6 1/4″ | 3 1/2″ |
| 4″ | 7″ | 3 3/4″ |
| 4 1/2″ | 7 5/8″ | 4 1/8″ |
| 5″ | 8 3/8″ | 4 1/2″ |
| 5 1/2″ | 9 1/8″ | 4 7/8″ |
| 6″ | 9 3/4″ | 5 1/8″ |
| 6 1/2″ | 10 1/2″ | 5 1/2″ |
| 7″ | 11 1/4″ | 5 7/8″ |
| 7 1/2″ | 11 7/8″ | 6 1/4″ |
| 8″ | 12 5/8″ | 6 5/8″ |
| 8 1/2″ | 13 3/8″ | 7″ |
| 9″ | 14″ | 7 1/4″ |
| 9 1/2″ | 14 3/4″ | 7 5/8″ |
| 10″ | 15 1/2″ | 8″ |
| 10 1/2″ | 16 1/8″ | 8 3/8″ |
| 11″ | 16 7/8″ | 8 3/4″ |
| 11 1/2″ | 17 5/8″ | 9 1/8″ |
| 12″ | 18 1/4″ | 9 3/8″ |
| 12 1/2″ | 19″ | 9 3/4″ |
Other info
The square root of 2 = 1.414
To find out the width to cut “diamonds” that will match up with a HST, take the finished width divided by the square root of 2 and add 1/2″ for seam allowances.
For example, for a 4″ finished width:
4” = 2 7/8 + ½” = 3 3/8
Here’s a simple design I drew up using Electric Quilt Software:
(C) Christa Quilts Inc. For personal use only.
Christa Quilts 
Thanks for the quilty math answers!!
Wow eq7 classes? Would love to attend one. Need more.
Fabulous to have both resources! If I were living nearby, I’d be at your lecture! thanks so much especially for the info on angles and how much you lose (need to add) with those 🙂
Thank you so much! This is awesome!
Math is the worse part of quilting for me so I do appreciate all your great info. I usually keep making a sample block till I get to the size I need.
Love this! Do you have a formula to figure out what size to cut flying geese? I can figure out the rectangle size but getting the two square sizes are hit and miss for me. Do you use the half square triange formula above? Thank you for this information. I have been looking for this information!
I found this link that has a cheat sheet http://www.mccallsquilting.com/mccallsquilting/articles/No_Waste_Flying_Geese_FREE_Block_Builders_Workshop_Video_Lesson
Thank you, awesome
Thank you Christa, this is really helpful. I think there may be an error in the on point triangles cutting table. I think the corner triangle for the 5½ inch finished block is incorrect at 4 1/8. Should it read 4 7/8?
Is the binding formula for binding sewn together straight or on the bias? (Great post, by the way!)
I have downloaded & save this, i must since i have had to put my EQ7 back on due to computer problems, i got this but when i go to my PJ i can’t find it i tried doing a search but can’t find it yet if i go in to EQ it under the exsisting projects just can’t seem to figure out where they being save to lol
Hugs Janice
Thank you Christa, wow what a useful document. Great that you so willing to share and teach. Much appreciated. You so inspiring