Yarn Calculator for Knitting & Crochet
Estimate how much yarn you need, how many skeins to buy, and how to substitute yarns for any knitting or crochet project. Works with both metric and imperial units.
1. Calculate Skeins from Pattern Yardage
Use this when your pattern already tells you the total yardage or meters required.
Results
Total yarn (with margin)
–
Skeins to buy
– skeins
We always round up to the next full skein so you don’t run out mid-project.
How this yarn calculator works
This yarn calculator is designed for knitters and crocheters who want quick, realistic estimates without doing math on paper. It supports both metric (meters, centimeters) and imperial (yards, inches) units and covers four common scenarios:
- You have a pattern with total yardage and want to know how many skeins to buy.
- You only have a gauge swatch and project dimensions.
- You want to substitute a different yarn than the one in the pattern.
- You have leftover yarn and want to know what you can make with it.
1. From pattern yardage
If your pattern already lists total yardage or meters, the calculation is straightforward:
Step 1 – Convert units if needed
If pattern and skein units differ, convert so they match (meters ↔ yards).
Step 2 – Add safety margin
\( \text{Total with margin} = \text{Pattern yardage} \times \left(1 + \frac{\text{margin \%}}{100}\right) \)
Step 3 – Skeins to buy
\( \text{Skeins} = \left\lceil \dfrac{\text{Total with margin}}{\text{Length per skein}} \right\rceil \)
The calculator applies the safety margin and always rounds up to the next full skein so you don’t run out.
2. From gauge swatch
When you don’t know the pattern yardage, you can estimate from a swatch:
- Knit or crochet a swatch at least 10×10 cm (4×4 in) in the stitch pattern you’ll use.
- Measure the swatch width and height.
- Unravel the swatch and measure how much yarn you used.
Swatch area
\( A_\text{swatch} = \text{width} \times \text{height} \)
Yarn per unit area
\( y = \dfrac{\text{yarn length used}}{A_\text{swatch}} \)
Project area
\( A_\text{project} = \text{project width} \times \text{project length} \)
Estimated total yarn
\( \text{Yarn total} = y \times A_\text{project} \)
The tool handles all conversions between centimeters and inches and between meters and yards, then adds your chosen safety margin and converts to skeins.
3. Yarn substitution
To substitute yarns safely, you need to match both gauge and total yardage. This calculator focuses on yardage:
Original total yardage
\( L_\text{orig} = \text{original skeins} \times \text{length per skein} \)
Adjusted for safety margin
\( L_\text{target} = L_\text{orig} \times \left(1 + \frac{\text{margin \%}}{100}\right) \)
Substitute skeins
\( \text{Sub skeins} = \left\lceil \dfrac{L_\text{target}}{\text{sub length per skein}} \right\rceil \)
After matching yardage, always knit or crochet a gauge swatch with the new yarn and adjust needle or hook size until you match the pattern gauge.
4. Leftover yarn ideas
For leftover yarn, the calculator simply totals your yardage and compares it to typical ranges for common projects. These are rough guidelines only; stitch patterns and sizes can change requirements significantly.
Tips for accurate yarn planning
- Swatch in pattern: If your project uses cables, lace, or textured stitches, swatch in that pattern, not plain stockinette.
- Measure after blocking: For garments and lace, block your swatch before measuring; blocking can change both size and yarn usage.
- Buy an extra skein for garments: Especially when dye lots matter. You can always use leftovers for matching accessories.
- Record your projects: Note actual yardage used for future reference; over time you’ll build your own personal yardage library.