All calculators

Quilt mathyou can check.

QuiltHelper is a set of free calculators for the arithmetic between the pattern and the fabric shop. Every answer shows how it was worked out, and every fabric amount rounds up, so the number you take to the counter is the number you need.

Open the calculators How we check the math
5Free calculators
20,000+Random quilt setups checked before every update
1/8Yard: every amount rounds up to the next one
0Accounts, sign-ups or emails needed

Why it exists

Built for the back of the pattern.

A small slip in the arithmetic turns into a second trip to the shop, and a dye lot that no longer matches.

Most quilting math happens in a margin: how much backing to buy, how many binding strips to cut, how wide to cut a border, what size square makes a 3" half-square triangle. None of it is hard, but it is full of small rules. Seam allowances, usable fabric width, how strips are joined and which way the backing is seamed all change the answer.

QuiltHelper does that arithmetic the same careful way every time. It shows the formula it used, draws the layout, and gives you an amount you can actually ask for at the cutting counter.

How we check the math

Four rules every calculator follows.

Each formula is written out on its calculator page with a worked example. Behind the pages, automated checks compare every calculator with results worked out by hand, from baby quilts to king and quilts wider than one panel of fabric.

  1. 01

    Fabric rounds up

    Yardage rounds up to the next 1/8 yard and meters to the next 0.1 m. Cut sizes in centimeters round up to the next millimeter.

  2. 02

    Seams are counted

    Patchwork seams are 1/4". Backing panels are joined with 1/2" seams, so every join uses 1" of width.

  3. 03

    Usable width, not bolt width

    Quilting cotton defaults to 42" usable once the selvages are trimmed. 108" wideback is treated as 104" usable.

  4. 04

    Nothing comes up short

    Strip and panel counts are checked so the pieced length or width always covers the size you need.

How a result is made

  1. Your measurements

    Width, length and the options you pick, in inches or centimeters.

  2. The written formula

    The same formula shown on the calculator page, with a worked example.

  3. Rounded up

    Every amount goes up to something you can actually cut or buy.

  4. Drawn to scale

    A diagram of the layout, so you can see the answer as well as read it.

The math was last checked in November 2026.

The calculators

Five tools, one way of working.

Good to know

What a calculator can't know

A calculator only knows the numbers you give it. Fabric widths vary, seams wander and some patterns use their own methods. Read every result alongside your pattern, and buy a little extra for directional prints, fussy cutting or pre-washing.

Who makes it

Designed and built by FRPROTECH

QuiltHelper is free to use, with no account and no sign-up. It will be kept free by advertising, which never changes a result.

Visit FRPROTECH

Found a number that looks wrong?

Tell us the calculator, what you entered and what you expected. Corrections are checked and fixed first.

Email info@quilthelper.comOther ways to reach us