Leathercraft, minus the guesswork
Free calculators and honest buying guides for people teaching themselves leatherwork. Work out your stitch pitch, how much leather to buy and the right thread — then see exactly which tool fits.
Calculators
Stitch Pitch Convertermm ↔ SPI, plus the right thread and irons for your pitch.Leather Project CalculatorSquare feet, hide cut and thickness for wallets, belts and bags.Thread Length EstimatorExactly how much thread to cut so you never run short mid-seam.Thickness ConverterTurn leather ounces into real millimetres and inches.Belt Length CalculatorBelt size, strap blank length and hole layout.Rivet Length SelectorThe right rivet or Chicago screw for your leather stack.Needle & Thread SelectorMatch needles to thread in mm, Tex or by pitch.
Start here
Why StitchMath
Tool-first, not blog-first
Every answer starts with a working calculator or a real chart — not 1,500 words before the point.
Honest about specs
We flag where sellers measure pitch differently and where leather thickness is only a range, so you buy the right thing once.
US units, mm too
Inches, feet and ounces first, with millimetres alongside — the way US makers actually work.