Work out the cast-on stitches and rows for a rectangular panel from the gauge you measured on your own swatch.
This calculator only works with the measurements you enter. It does not create a pattern for you and it does not redesign increases, decreases, sleeves or fit.
What to have ready before calculating
A swatch knitted with the yarn and needles you will actually use. Measure only the patterned area, leaving the edges out.
The width of that area and its stitch count, and the height and its row count. Decimals are fine if a partial stitch is included.
Whether you measured after washing and drying the swatch, or before washing it.
The target width and height of the panel you want to make. This is the size of the patterned area, not the full outer size.
The horizontal pattern repeat in stitches and the total edge stitches for both sides. If there is no pattern, the repeat is 1.
To also calculate yarn, you need the dry weight of the swatch, the area that weight covers, and the weight and length of one ball from the yarn label.
Please check your entries
Swatch measurements
The length you measured across the patterned area only, with the edges left out. A 10 cm span is usual, and decimals are allowed.
The number of stitches inside the span you measured. If a half stitch is included, enter a decimal such as 20.5. This is not the stitch count of the finished piece.
The height measured on the same swatch and in the same measurement state as the width.
The number of rows inside the height you measured. Decimals are allowed.
Target size and pattern
The width of the patterned area. It is not the full outer width including edge stitches and seam allowance.
The height of the patterned area. If the target is smaller than a single row, no workable instruction can be produced.
The number of stitches in one set of the pattern. Only whole numbers from 1 to 1000 are accepted, and if there is no pattern enter 1. Vertical pattern repeats are not calculated.
The total for both sides added together, not the count for one side. For one stitch on each side, enter 2. Edge stitches are added to the cast-on total once and are left out of the panel width calculation.
Yarn required (optional)
This is calculated on the assumption that with the same yarn and the same stitch pattern, yarn use is proportional to area. That assumption does not hold once the yarn or the pattern changes. Do not apply it to three-dimensional shapes either.
Without these conditions the area-proportional model cannot be used. Tick this only if you have checked it yourself. If it is not ticked, yarn required is not calculated.
The weight of the whole swatch on a scale. It must refer to exactly the same piece as the area below.
The area of the whole swatch you weighed. It can differ from the inner span you measured for gauge, so work it out separately. A 10 cm by 10 cm piece is 100.
The sum of every surface you will actually knit, such as front, back and sleeves. Decide for yourself whether to include the edges. It is not worked out automatically from the target panel size above.
How many percent extra you choose to prepare. Only values from 0 to 100 are accepted. This is your own margin, not a statistical confidence interval.
The value printed on the label of the yarn you will actually buy.
The length from the same label. Do not mix the weight and length of different yarns.
The length of the same yarn you already own. Enter 0 if you have none. Do not add lengths of other yarns.
Nothing calculated yet. Enter your swatch measurements and target size, then press Calculate working numbers.
Your entries have changed. Please calculate again.
Results
Estimated from your measurements. If the pattern, tension or washed state differs, the finished size can differ too.
Gauge
Stitch gauge
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The measured stitch count divided by the measured width.
Row gauge
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The measured row count divided by the measured height.
Ideal panel stitches
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The target width multiplied by the stitch gauge. This comes before matching the pattern repeat, so it may not be a whole number.
Cast-on options
Rows
Panel rows
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The target height multiplied by the row gauge, rounded to the nearest whole number.
Estimated panel height
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The rounded row count converted back into a length. It may differ slightly from your target.
Yarn required
Estimated weight needed
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The weight per unit area multiplied by the total area and by the extra you chose to prepare.
Estimated length needed
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The weight converted into length using the weight-to-length ratio of one ball.
Extra balls to buy
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The shortfall left after subtracting the yarn you have, divided by the length of one ball and rounded up, because yarn can only be bought by the ball.
Extra applied
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The margin you entered. It is not a statistical confidence interval.
Calculated on the assumption that yarn use is proportional to area with the same yarn and the same stitch pattern. Once the yarn or the pattern changes, or three-dimensional shaping is involved, this figure no longer holds.
What this result assumes
That the gauge of your swatch stays the same in the finished piece. Tension varies from person to person and from day to day.
That the panel is a rectangle. Increases, decreases, raglans, sleeves and fit are not part of the calculation.
That edge stitches are added to the cast-on total once only and are left out when the panel width is converted.
That yarn use is proportional to area with the same yarn and the same stitch pattern.
That you chose whether the measurement state is before or after washing, since this calculator does not convert one into the other.
How it is calculated
The steps below are used. Every value comes from what you entered, and nothing is looked up automatically.
Divide that value by the pattern repeat and take the whole numbers just below and just above it as the options, then panel stitches = option × repeat stitches
Cast-on total = panel stitches + total edge stitches
Estimated panel width = panel stitches ÷ stitch gauge, and the difference from the target is shown with its sign
Estimated weight = swatch weight ÷ swatch area × total area × (1 + extra to prepare ÷ 100)
Estimated length = estimated weight × length of one ball ÷ weight of one ball, extra balls = shortfall in length ÷ length of one ball rounded up
Two options are shown because the choice that matches the pattern repeat exactly and comes closest to the target width usually falls just below or just above it. If the target width is narrower than one full repeat, there is only one option.
Made-up example
A made-up example for checking the screen. These are not the figures of any particular pattern or real product.
A swatch with 20 stitches in 10 cm and 28 rows in 10 cm, used for a panel 37 cm wide and 50 cm high. The pattern repeat is 6 stitches and the total edge stitches are 2.
Ideal panel stitches 74. Option A is 72 panel stitches plus 2 edge stitches, so cast on 74, estimated width 36 cm
Option B is 78 panel stitches plus 2 edge stitches, so cast on 80, estimated width 39 cm
Panel rows 140, estimated height 50 cm
If the same yarn used 5 g for 100 cm², the total knitted area is 2,000 cm² and the extra to prepare is 10%, you need 110 g. With a yarn of 50 g per 100 m that is 220 m, and if you already have 100 m you need to buy two more balls.
This example does not guarantee the finished size either. If your knitting turns out differently, measure a new swatch first.
Frequently asked questions
Why is the result always an estimate?
Because gauge itself is a measurement taken from a single swatch. Once tension, washing, pattern, needles or the condition of the yarn change, the same stitch count can give a different finished size. That is why this calculator never presents a settled figure and always shows the result as an estimate.
If there are two options, which one should I pick?
There is no single right answer. You are shown one option narrower than the target and one wider, so choose for yourself based on fit, where the pattern gets cut off, and the yarn you have left. The difference between the two may even be smaller than your measurement error.
Are edge stitches added to each side separately?
No. The value you enter is already the total for both sides, so it is added to the cast-on total once only. For one stitch on each side, enter 2. Edge stitches are left out when the panel width is converted.
Can I calculate with measurements taken before washing?
You can, but the result will be marked as a provisional pre-wash measurement. Many yarns change size after washing, so measure again after washing and drying if you can. Do not mix them, such as an unwashed width with a washed height.
Will it create a sweater pattern for me?
No. It only calculates supporting numbers for a panel that can be treated as a rectangle. Increases, decreases, necklines, sleeves and raglans are for you to design or to follow from a pattern.
What this calculator does not do
It does not create a pattern for you. It does not redesign increases, decreases, sleeves, necklines or fit.
It does not match vertical pattern repeats or any required starting row.
It does not convert a pre-wash gauge into a post-wash gauge.
It does not rework the yarn requirement for three-dimensional shapes or a different stitch pattern.
It does not look up yarn prices, stock or where to buy.
It does not analyse uploaded pattern files. There is no need for that either.
Related calculators
If you need to sort out the area first, the calculators below will help.
Area Converter
— Use it when an area you noted in square metres or another unit has to become square centimetres.
Tile and Paint Quantity Calculator
— A calculator that works the same way: it finds the material quantity from an area, adds a margin and rounds the purchase quantity up.