Enter the width and height of the area you measured, together with the stitches across that width and rows over that height. Use measurements and counts from the same area. All estimates use your swatch; the defaults are illustrative.
Enter lengths in metres: divide centimetres by 100 or multiply inches by 0.0254. For example, 10 cm is 0.10 m and 4 inches is 0.1016 m. Results show gauge per centimetre and per inch. Keep the two fixed reference lengths at their supplied values.
Use the yarn, stitch pattern and needles or hook intended for your project. The Craft Yarn Council’s swatch guidance explains why checking gauge before beginning matters.
Let S be counted stitches, R counted rows, w and h the measured swatch width and height in metres, and W and H the target width and height in metres.
- Stitches per centimetre = S × 0.01 ÷ w.
- Rows per centimetre = R × 0.01 ÷ h.
- Stitches per inch = S × 0.0254 ÷ w.
- Rows per inch = R × 0.0254 ÷ h.
- Estimated target stitches = S × W ÷ w.
- Estimated target rows = R × H ÷ h.
The Craft Yarn Council instructor handbook calculates stitch gauge by dividing counted stitches by measured inches. The row formula applies the same count-per-length definition vertically. Target counts follow by multiplying gauge by target length, assuming unchanged gauge. NIST gives the exact conversion of one inch to 0.0254 metres; one centimetre is 0.01 metres.
| Example | Swatch inputs | Target inputs | Gauge | Estimated target counts |
|---|---|---|---|---|
| Metric rectangle | 20 stitches across 0.10 m; 28 rows over 0.10 m | Width 0.30 m; height 0.40 m | 2 stitches/cm; 2.8 rows/cm; 5.08 stitches/in; 7.112 rows/in | 20 × 0.30 ÷ 0.10 = 60 stitches; 28 × 0.40 ÷ 0.10 = 112 rows |
| Inch-based rectangle | 18 stitches across 4 in (0.1016 m); 24 rows over 4 in (0.1016 m) | Width 12 in (0.3048 m); height 8 in (0.2032 m) | Approximately 1.7717 stitches/cm and 2.3622 rows/cm; 4.5 stitches/in; 6 rows/in | 18 × 0.3048 ÷ 0.1016 = 54 stitches; 24 × 0.2032 ÷ 0.1016 = 48 rows |
| Fractional result | 21 stitches across 0.10 m; 29 rows over 0.10 m | Width 0.255 m; height 0.305 m | 2.1 stitches/cm; 2.9 rows/cm; 5.334 stitches/in; 7.366 rows/in | 53.55 stitches and 88.45 rows before choosing practical whole counts |
The outputs are proportional estimates displayed to four decimal places. They do not automatically round to whole stitches or rows, enforce pattern repeats, or add edge stitches, turning chains, seams or borders.
For a plain rectangle, choose the nearest suitable whole counts. If the rectangle must be at least the requested size, choose counts above the estimates, subject to your pattern requirements. For example, 53.55 stitches and 88.45 rows become 54 stitches and 89 rows when rounding upward. A repeat pattern may require a different choice.
Use the same construction and finishing conditions for the swatch and project. These calculations assume uniform gauge across a flat rectangle and do not model shaping, stretch, drape, yarn quantity or changes in tension.
Accepted swatch dimensions are 0.001–10 m; target dimensions are 0.001–100 m, in 0.0001 m increments. Counts are 0.25–10,000 in quarter-count increments. These are calculator limits, not recommended project sizes. All measured dimensions and counts must be positive. An unavailable result indicates invalid arithmetic or an out-of-range calculation; it is not a zero count.
Is a 10 cm swatch the same size as a 4 inch swatch?
No. Four inches is exactly 10.16 cm. Enter the actual measured length: 0.10 m for 10 cm or 0.1016 m for 4 inches.
Can I use the stitch count to estimate rows?
Measure rows separately. Stitch gauge describes horizontal density, while row gauge describes vertical density. The calculator uses your separate counts and measured dimensions.
Is the stitch estimate a crochet starting-chain count?
It estimates the number of stitches across the fabric. Determine the foundation chain, turning chains and any additional stitches from your pattern.
Formula sources and swatch guidance
- Craft Yarn Council — Certified Crochet Instructors Program: calculating stitch gauge from a measured swatch.
- NIST — SI Units: Length; exact inch-to-metre conversion.
- Craft Yarn Council — Reading Instructions & Other Basics: checking gauge before beginning a project.
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