Craft Yarn Council
Hooks & Needles
Metric and US hook and needle size tables; gauge-swatch qualification.
Editorial policy
Every factual page should show where the number came from.
The source set below was checked on September 13, 2026. We prefer formal standards and primary manufacturer guidance, then clearly labeled industry guidance when no universal standard exists.
Open source
Craft Yarn Council
Steel Crochet Hook & Crochet Thread Sizes
Steel-hook numbering and its reverse relationship to hook diameter.
Craft Yarn Council
Standard Yarn Weight System
Yarn weight categories, common names, gauge ranges, and tool ranges.
Craft Yarn Council
Head Circumference Chart
Head-circumference ranges by age grouping.
Warm Up America! Foundation / Craft Yarn Council
Warm Up America! afghan sizing brochure
Example baby, lap, child, and adult afghan sizes assembled from 7 × 9 inch sections.
DMC
What Fabric Should You Use for Cross Stitch?
Counted-stitch fabric guidance and stitching over two threads.
National Institute of Standards and Technology
SI Units — Length
Exact inch-to-millimeter relationship: 1 inch equals 25.4 millimeters.
Seamwork
How to Sew a Basic Seam
Definition of seam allowance and pattern-first guidance for choosing it.
KnitPro
Choosing the Right Cable Length for Circular Needles
Manufacturer guidance for matching common circular-needle lengths to project types.
American Quilter's Society
Quilt Sizes Chart
Suggested quilt-dimension guidance; not a formal sizing standard.
American Quilter's Society
The Final Step: Binding Cuts
Straight-grain binding length guidance, including a 12-inch allowance for joins, corners, and finishing.
Yarnspirations
How to Measure Knit Gauge
Why a representative swatch should use the same yarn and stitch pattern as the finished project.
Purple Innovation
Mattress Sizes & Dimensions
Typical US mattress top dimensions used as inputs to the quilt sizing formula.
SCHMETZ
Anatomy of a Household Sewing Machine Needle
NM/Singer size conversion and explanation of the metric NM system.
Corrections policy
Correct the data, then the prose.
Conversions are stored in shared datasets so one correction updates every dependent view. Calculators use isolated pure functions with manually verified examples.
When sources disagree, we do not average them. We identify the scope of each source, prefer the more authoritative or directly applicable one, and keep manufacturer variation visible.
Material corrections update the review date and are checked across charts, detail pages, printables, metadata, and tests.