Knitting & sewing math, done for you
CraftCalc turns your gauge swatch and a few measurements into yarn estimates, stitch counts and size adjustments you can trust — with the approximations labeled honestly and every reference table traced to a published source.
Calculators
Both tools run entirely in your browser — nothing is uploaded, and the method behind every number is written out on the page.
Yarn Estimate Calculator
Gauge plus piece dimensions to metres and yards of yarn needed, ball count, and a cross-check against published yardage tables.
ToolPattern Resize Calculator
Percentage scaling with stitch and row counts at your gauge (with ribbing even/odd checks), plus sewing grade differences from a standard size table.
Printable cheat sheets
Print-friendly reference tables with every value traced to a published standard. Last verified: 2026-11-16.
Knitting Needle & Crochet Hook Size Chart (US / UK / metric)
One printable table converting metric mm to US and old UK needle sizes, plus hook letter sizes — from Craft Yarn Council and manufacturer charts.
Cheat sheetStandard Body Measurement Tables
Craft Yarn Council women's and men's garment sizing plus head circumferences, and a sewing size chart for cross-checking pattern sizes.
Guides
The making math behind the tools — method content, honest about what is exact and what is approximation.
Gauge Swatching, and Why It Actually Matters
How to swatch, measure, and read a gauge like a pattern designer — and what a half-stitch off really does to your sweater.
Knitting mathKnitting Math Explained: Stitches and Rows to Dimensions
Turn "18 stitches and 26 rows per 10 cm" into exact widths and lengths — the one formula every knitter should know.
ResizingAdjusting a Knitting Pattern Larger or Smaller
The percentage method, worked step by step — and its real limits for armholes, necklines and anything shaped.
Yarn planningYarn Substitution Math: Can You Use This Instead?
Weight categories, metreage versus grams, and the total-metres calculation that answers "will I run out?"
SewingSewing Grade Rules, Explained Simply
What "grading" means, how size differences are distributed across a pattern, and which references to trust.
SewingFabric Yardage Estimating for Common Projects
Published yardage charts for garments at 45" and 60" widths, plus how to sanity-check them for your size.
ReferenceReading a Yarn Label: What Every Field Means
Ball-band decoding — weight, metreage, gauge, dye lot, care symbols — and which numbers drive the math.
Yarn planningCrocheting vs Knitting: Which Uses More Yarn?
An honest answer with no invented ratios — what changes yarn usage, and what the community experiments found.
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Start where your project is stuck.