About This Site
Free Fabric Calculator is a website that tells you how much fabric to buy and how to cut it. It has three calculators: a general fabric calculator for any list of pieces, a quilt backing calculator and a curtain fabric calculator. There’s nothing to sign up for or install.
Who Made It
I’m Rishabh, an independent developer. I built and run this site on my own. I’m not a professional sewist or quilter, so the site sticks to what can be measured and worked out: sizes, widths, seam allowances and lengths. For anything about technique, your pattern’s instructions come first.
Why It Exists
Working out fabric is simple arithmetic with a few traps. Fabric often can’t use its full labeled width, every seam takes a little from each piece, a curtain is joined from whole or half widths, and shops sell length in steps. I wanted one place that handles those details and shows its working: where each piece goes, which way to seam a backing, and why the answer is what it is.
How the Answers Are Worked Out
- All the math runs in inches. Centimeters are converted on the way in and out.
- The amount to buy is rounded up, never down, to the step you choose (1/8 yd by default, or 0.1 m). The exact length is shown too.
- Every allowance is on screen. Seam allowances, backing overhang, hems, pattern repeats and extra for shrinkage are inputs you can see and change. The general fabric calculator adds nothing extra unless you ask.
- Each page explains its method with a worked example below the calculator. Every amount in that text is produced by the same calculator code when the site is built, so the text and the tool agree.
Typical values that vary between brands, such as usable fabric widths, batting package sizes and standard quilt sizes, are checked against at least two published sources, and the pages call them “typical”.
How the Math Is Tested
The calculations are kept separate from the page, as plain code that can be checked on its own. Automated tests run them against worked examples with known answers, including awkward cases such as a length that lands exactly on 3 yd (it must not round up to 3 1/8), a piece that only fits sideways, and fractions typed as 60 1/2 or 60-1/2. The tests run automatically on every change, and changes are published only once they pass.
Get in Touch
Found a wrong result or something unclear, or have an idea? Email hello@freefabriccalculator.com, or see the contact page. You can also read the privacy policy and the terms of use.