About FibreCalcs

FibreCalcs exists because buying fabric shouldn’t require a maths degree — but getting it wrong means a second trip to the shop.

Who builds this

My name is Dan Dadovic. I’m a Commercial Director and PhD Candidate in IT Sciences based in Northumberland, UK. By day I build web applications. By evening I’m the person standing in front of a fabric bolt, phone calculator open, trying to work out how much curtain lining to buy.

I started making curtains at home a few years ago. Then quilts. Then I tried my hand at garment sewing. Every project started the same way: searching for a calculator that could tell me exactly how much fabric to buy, and finding either nothing, or a tool buried behind ads that didn’t account for pattern repeats, seam allowances, or the fact that quilting cotton comes in 42-inch widths, not 45.

I’m a developer, so I built what I needed. FibreCalcs is the result — a set of free, focused calculators for textile and fibre crafts. I am not a professional seamstress, quilter, or textile engineer. I’m a maker who codes and a coder who makes. The formulas on this site come from published textile references, industry standards, and the kind of hard-won knowledge you pick up after cutting curtain drops short twice.

Why this site exists

The textile and fibre craft space is underserved by decent online tools. Most fabric calculators on the web were built a decade ago, don’t support metric, ignore pattern repeats, and round to the nearest whole yard. That’s fine if you don’t mind over-buying by half a metre every time, but for anyone who values precision — or is working on a budget — it’s not good enough.

FibreCalcs covers sewing, quilting, knitting, and crochet. Every calculator supports both imperial and metric units, rounds to real-world purchase increments (eighths of a yard or 10cm), and shows you the working behind the result. The goal is straightforward: help you buy the right amount of material the first time.

How the calculators are built

Every formula on FibreCalcs is sourced from a published reference and verified against known values. I don’t invent maths — I implement the standard calculations that professional curtain makers, quilters, and knitters have used for decades, then make them accessible in a format that doesn’t require you to remember the formula yourself.

Each calculator goes through the same process before it goes live.

• The formula is researched and cross-checked against at least one published textile reference.
• Worked examples are run through the calculator to verify every intermediate value and final result.
• Known-value tests are written and run automatically to catch regressions.
• The source is cited on the calculator page itself, so you can verify the maths independently.

You can read more about this process on the editorial policy page.

The broader picture

FibreCalcs is part of a portfolio of calculator sites I build for underserved niches. The approach is always the same: find a community that needs better tools, build them properly, and give them away for free. Other sites in the portfolio include tools for printing, electrical work, and construction. Each site is purpose-built for its audience — no shared templates, no generic designs, no one-size-fits-all calculators.

I build these sites with the help of AI tools, and I’m transparent about that. AI helps with code generation, content drafting, and testing. But every formula is human-verified against textile industry sources, every worked example is checked by hand, and every design decision is made with the specific needs of makers in mind. The AI helps me build faster; it doesn’t replace the domain research.

What this site is not

FibreCalcs is not a replacement for measuring your own project. No calculator can account for every variable — your fabric might have a wider selvage, your tension might run tight, your curtain pole might not be perfectly level. The results here are planning aids, not guarantees.

Always buy a bit extra. Measure twice, cut once. And if you spot an error in any calculation, I genuinely want to hear about it — use the feedback form on any page to let me know.

Get in touch

Spotted a bug? Found a formula error? Want to suggest a calculator I haven’t built yet? Use the feedback form at the bottom of any page. I read every submission and respond to as many as I can.

FibreCalcs is free, has no ads, and requires no login. If it saves you a trip to the fabric shop, it’s done its job.