How do I calculate how many stitches to cast on?

Measure your gauge over at least 10 cm (or 4 in), then divide the number of stitches by the measured width to get stitches per cm or inch. Multiply this by the desired finished width and round to the nearest whole number. The Cast-On & Rows tab does this automatically and can also round to the nearest multiple for ribbing.

How can I increase or decrease stitches evenly across a row?

To increase evenly, subtract the starting stitch count from the final stitch count to get the number of increases. Divide the starting stitch count by the number of increases plus one to get the spacing between increases. For decreases, subtract the final stitch count from the starting count and divide the starting count by the number of decreases. The Increases & Decreases tab calculates the spacing and gives you a written instruction.

How do I estimate how much yarn I need?

Knit a swatch and measure how many meters or yards of yarn it used and the area of the swatch. Divide yarn length by swatch area to get yarn per square cm or inch, then multiply by the area of your project. The Yarn Usage tab lets you enter swatch size and yarn used, then estimates total yarn and number of skeins.

Can I use this knitting calculator for both metric and US units?

Yes. You can choose centimeters or inches for all size-related inputs. The calculator keeps units consistent within each tab and does not force you into one system.

Do I still need to knit a gauge swatch?

Yes. Any calculator can only be as accurate as the gauge information you provide. Always knit and wash a swatch in the same yarn, needles, and stitch pattern you will use in your project, then measure it carefully before using the calculator.

Knitting Calculator

Plan your knitting projects with one tool: convert gauge, calculate cast-on stitches and rows, distribute increases/decreases evenly, and estimate yarn usage for any size.

1. Gauge & Size Converter

Convert between stitches/rows per 10 cm and per 4 in, and see how your gauge affects finished size.

Gauge unit

Stitches in swatch

Rows in swatch

Measured swatch width

Measured swatch height

How this knitting calculator works

This knitting calculator combines several tools that knitters usually have to use separately: gauge conversion, cast-on and row counts, even increases/decreases, and yarn estimation from a swatch. It is designed to be pattern-agnostic, so you can use it for sweaters, scarves, shawls, blankets, hats, and more.

1. Gauge & size formulas

Gauge is the number of stitches and rows per unit of length. From a swatch:

Stitch gauge (sts per unit):

\(\text{sts per unit} = \dfrac{\text{stitches in swatch}}{\text{swatch width}}\)

Row gauge (rows per unit):

\(\text{rows per unit} = \dfrac{\text{rows in swatch}}{\text{swatch height}}\)

The tool converts between “per 10 cm” and “per 4 in” using simple proportional scaling.

2. Cast-on stitches and rows

Once you know your gauge, the number of stitches to cast on for a given width is:

\(\text{cast-on stitches} = \text{stitch gauge} \times \text{desired width}\)

\(\text{rows} = \text{row gauge} \times \text{desired height}\)

The calculator can also:

Add or subtract ease from the width before calculating.
Round to the nearest multiple (for ribbing, lace repeats, etc.).

3. Evenly spaced increases and decreases

To increase evenly across a row, you need to know how many stitches to add and how far apart to place them.

Number of increases: \(n = \text{final sts} - \text{starting sts}\)

Spacing (approx.): \(s = \dfrac{\text{starting sts}}{n + 1}\)

The calculator uses this spacing to generate a readable instruction like:

“Knit 7, inc 1, *knit 8, inc 1; repeat from * to end of row.”

For decreases, it uses the same idea with \(n = \text{starting sts} - \text{final sts}\).

4. Estimating yarn from a swatch

Yarn usage is roughly proportional to the area of the fabric, assuming the same stitch pattern and gauge.

Swatch area: \(A_s = w_s \times h_s\)

Project area: \(A_p = w_p \times h_p\)

Yarn per area: \(Y_a = \dfrac{L_s}{A_s}\)

Total yarn: \(L_p = Y_a \times A_p\)

Number of skeins: \(\text{skeins} = \dfrac{L_p}{L_{\text{skein}}}\)

Where \(L_s\) is the yarn length used for the swatch and \(L_{\text{skein}}\) is the length per skein.

Practical tips

Always wash and block your swatch before measuring gauge.
Measure over the full swatch size (not just 10 cm/4 in) for better accuracy.
For garments, include ease based on how fitted or oversized you want the piece.
For complex shapes (raglans, yokes, shaped shawls), use this tool section by section (e.g., body, sleeves, borders).

Knitting Calculator

1. Gauge & Size Converter

Size from stitch count

2. Cast-On & Row Calculator

3. Even Increases & Decreases

Written instruction

4. Yarn Usage & Skein Estimator

Swatch

Project