About Quilt Backing Calculator

Who runs this site

I'm Ian Welkins. I build calculator websites for crafts where a wrong number costs real material — and quilting is exactly that kind of craft. A yardage figure that is half a yard short doesn't produce a slightly worse quilt; it produces a second trip to the fabric shop and, if the bolt has sold out, a different quilt than the one you planned.

The site started with the backing question — how much fabric for the back of this quilt? — because it is the calculation quilters make most and guess worst. The other tools followed the same logic: each one answers a single fabric question, shows its method openly, and checks its arithmetic against published sources wherever a source exists — and states its own modeling choices where it makes them.

How the numbers are sourced

Most formulas on this site follow published quilting methods, and each calculator page names the source it follows: John Flynn's diagonal backing formula, Missouri Star Quilt Co.'s perimeter-plus-allowance binding method, The Warm Company's standard pre-cut batting package sizes, and the commonly published quilt and mattress size charts. The diagonal backing calculator implements Flynn's formula exactly, worked example included, and the page reproduces his own numbers so you can verify it. A few tools, though, rest on modeling choices of this site's own rather than a published formula — the per-panel usable-width model behind the backing calculators, and the way the sashing and border tools pack strips across a fabric width. Where a calculator makes a modeling choice like that, the page states the choice plainly and tells you how to adapt the result.

Every worked example on the site is generated by the same code that runs the calculators, and that generated output is verified in QA against hand-computed cases. When a quilter reports a discrepancy, it is investigated and, if the site is wrong, corrected publicly — the editorial policy describes how, and the error report form is always open.

What the site is not

It is not a shop: nothing is sold here, and no calculator result is influenced by anyone's fabric inventory. It is not a pattern library or a tutorial channel — it does one job, the arithmetic, and links you onward for the rest. And it is not finished: quilting has more fabric questions than any one site launch covers, and the toolbox grows as readers ask. Start with the backing calculator — it is the tool the site is named for, and still the one most quilters need first.