About FabricMeasure

FabricMeasure is an independent site publishing fabric and sewing calculators that show their working. It is built and maintained by one person, carries no advertising yet and is intended to be funded by advertising in future, and takes no payment from fabric retailers or manufacturers.

Why it exists

FabricMeasure exists because every fabric calculator I found gave a number and no reasoning. When two of them disagreed there was no way to tell which had assumed a 15 cm heading and which had assumed 25 cm — so I built one where every allowance is visible, editable, and shown in the arithmetic.

The result is a small set of tools built around one idea: a number you cannot check is not much use. Every calculator shows the arithmetic that produced its answer, exposes every allowance it used, and states the assumptions a professional might argue with rather than burying them.

How the figures are checked

• The prose is generated, not written. The worked examples and reference tables in the supporting text are rendered from the same functions the calculators run, so the explanation cannot contradict the tool.
• The maths is unit-tested, including the awkward cases: a drop exactly on a pattern repeat boundary, a measurement entered in inches whose conversion lands a nanometre past that boundary, fabric too narrow to work at all. The tests run as part of every build, so a failing calculation cannot ship.
• The tools are cross-checked against each other. Where two calculators share a piece of arithmetic — the width solver, the pattern-repeat rounding — they import it rather than each keeping a copy, and a test asserts the standalone tool and the calculator that composes it cannot drift apart. Every assumption the maths makes is written out on the methodology page.
• The curtain results have been checked against other people's calculators. Eleven comparisons against three published calculators in two markets, recorded case by case on the methodology page along with every difference and what accounts for it. Nothing was found that the method here does not deliberately do — and where it differs, it differs in the direction of buying a little more cloth rather than a little less. Internal consistency is not the same as being right, which is why that comparison exists rather than being promised.
• Each tool carries a method version. When the maths changes the version bumps, so a figure you saved last month can be told apart from today's.

Independence

The site currently carries no advertising and loads no advertising script. It is intended to be funded by advertising in future, and when that happens the ads will be clearly labelled and never placed above or inside a calculator. There are no sponsored recommendations and no affiliate links, and no advertiser will have any say in what the calculators say; if any of that changes it will be disclosed here and on the privacy page before it appears anywhere else.

Who wrote it

Wickeey, web developer. Corrections, disagreements and reports of a wrong result are all genuinely welcome — get in touch, or use the "Report a wrong result" link on any calculator, which pre-fills the exact inputs that produced it.