15 May 2020

Rotary Cutting Formula Calculators for Quilters: The game changer

Rotary Cutting Formula Calculators for Quilters: The game changer

After I had been quilting for a while, I discovered there were formulas for making certain quilt blocks faster. I thought this was amazing and proceeded to find all the formulas I could. This was great but they had to be calculated properly to work. Sometimes I would enter a number wrong or add a number when I was supposed to divide. Then there was the problem with cheat sheets. They could be cumbersome and didn’t include the block assembly instructions.

After a while, I tried finding a quilting app that would do the formulas for me but with no luck. I considered making my own app but that would be too expensive. Then, I discovered an online calculator builder (UCalc) where I could create my own calculators. I created calculators for ten quilt block formulas. The formulas could now be calculated instantly and each one included assembly diagrams. 

I'm now sharing my Quick Block Calculators with the quilting community free of charge. I hope they help those of you who may have been as frustrated as me with block formulas. Enjoy!


•  All calculations have been tested for accuracy.
•  All measurements are in inches.
•  All instructions assume a basic knowledge of rotary cutting.
•  The formula for each block is included with each calculator.

Finished Block
•  Block dimensions after it has been sewn into a quilt.

Unfinished Block
•  Block dimensions before it has been sewn into a quilt i.e. finished block dimensions plus seam allowance.

Parent Squares
•  The squares you make using the formula. These squares are used to build your block.

Square Up
•  Trimming a block to its correct size.

•  Round up uneven results to the nearest even fraction or round number.
I use this handy decimal to a fraction conversion table.
•  Double-check your results before cutting your parent squares.
•  Make a test-run block before cutting your good fabric.
•  Cut the parent squares accurately.
•  Use a scant ¼ inch seam allowance to make the block slightly larger and easier to square up.

1. Scroll down to find the block you want to make.
2. Depending on the formula, enter the finished or unfinished block size you need.
3. Find the parent square size(s) in the orange box. If required, round up the result.
4. Cut the number of parent squares required.
5. Follow the assembly diagrams provided to make the block.
6. Square up block if necessary.

Calculators . . .


  1. This is awesome, Monica! Thank you for sharing these quilt block calculators.

  2. Alison - this looks incredibly useful Monica, thank you very much for sharing it. I am currently drowned in UFOs (Unfinished objects!) but looking forward to using this tool.

  3. I have already used these calculators several times for different projects. Thank you so much for creating and sharing them. It has made my life so much easier!

  4. I've been looking to find these all in one place. Thank you for getting this together. It sure saves a lot of time.

  5. Thank you for preparing this awesome fabric calculator. Your generosity in sharing your creation is much appreciated. I'm sure I will make good use of it, as will many other quilters.

  6. Wow! This is a gold mine. I often create my own patterns and this will be so helpful! Thank you, thank you!

  7. What a fantastic idea. Thank you see much for sharing. Now I will show my ignorance in some computer things. To use them do I just go to your site or can they be downloaded.

  8. Thank you for sharing! These will come in handy.

  9. Thank you so much Monica! Your thoughtfulness and generosity are much appreciated.

  10. This is awesome, Monica. Thank you for making this easy & having it all in one easy to find place!

  11. Thank you for the sharing, very helpful.