Knitting yarn yardage estimator

Enter stitch_count, gauge, and yarn_per_stitch in one consistent length unit for the consumption figure; the engine multiplies stitch count by yarn per stitch to get raw yardage, multiplies gauge by yarn per stitch to report yarn used by one unit-wide row, and divides stitch count by gauge to report how many unit widths the stitch total represents. Optional waste_percent scales the raw length for tails and seams without inventing a hidden fudge factor. Optional row_gauge adds implied fabric area, and optional skein_length converts the shopping figure into whole skeins. Zero or negative stitch counts, gauges, or consumption values are rejected with invalid_input, because a non-positive count or density cannot describe a knitable project. Successful API calls cost $0.002 per request.

What knitting yarn yardage from stitch count means

Knitters estimate yarn in several ways, and this landing is the path that starts from a stitch total rather than from finished width and height. A pattern may publish a stitch count for the body, sleeves, and neckband; a digital counter may report how many stitches you have already worked; or you may add the stitches in each chart repeat yourself. Gauge is not decoration. Once you also know how much yarn one stitch consumes at the gauge you will actually knit, the raw length is a product: yarn_length equals stitch_count times yarn_per_stitch. It is the stitch density of the fabric that produced that consumption figure, and the engine uses it to report yarn_per_unit_width (gauge times yarn_per_stitch) so you can sanity-check one unit-wide row against a measured row, and stitch_widths (stitch_count divided by gauge) so you can see how many unit widths the stitch total represents if laid as a single course. Optional waste_percent then scales yarn_length into yarn_with_waste for tails, seams, and a little gauge drift; the default is zero so the tool never silently pads a shopping list. Optional row_gauge unlocks implied_area as stitch_count divided by gauge times row_gauge, and yarn_per_unit_area as the product of consumption and both densities. Optional skein_length turns yarn_with_waste into a whole-skein buy quantity with a ceiling. There is no brand database, no hidden ease table, and no random waste factor: the engine either multiplies and divides the finite positives you sent or rejects the input with invalid_input. This is not a crochet dimension estimator, not a cast-on planner, and not a skein-substitution calculator; those are different search intents with different required fields.

How to call the API and what comes back

Every required field must be strictly positive; values at or below one times ten to the minus fifteen are treated as non-positive and rejected, which covers the required zero and negative measurement errors as well as empty counts. Row and skein fields appear only when you sent those optionals; omitted keys are omitted, never null. Send a JSON body with three required finite positive numbers: stitch_count (aliases stitches, total_stitches, sts, stitchCount, project_stitches), gauge (aliases stitch_gauge, sts_per, spi, stitches_per_unit, gauge_stitches), and yarn_per_stitch (aliases consumption, yardage_per_stitch, yps, length_per_stitch, yarnPerStitch). Absolute values must stay within the published limit of one trillion so intermediate products remain finite in IEEE double precision on the Worker and in the browser. Optional waste_percent (aliases waste, ease_percent, extra_percent) is a number from zero to one hundred and defaults to zero. Optional row_gauge (aliases rows_per, rpi, gauge_rows, rows_per_unit) must be strictly positive when present. Optional skein_length (aliases hank_length, ball_length, yards_per_skein, metres_per_skein) must be strictly positive when present. Optional precision (aliases decimals, dp) chooses how many decimal places to expose, defaulting to ten and capped at fifteen so JSON goldens stay stable across runs. On success the response echoes rounded inputs, sets yarn_length and yarn_with_waste, adds yarn_per_unit_width and stitch_widths, sets method to knit_stitch_count_yardage, and includes formula, message, and an ordered steps array. Failed validation returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item.

Measuring consumption, units, and how this differs from nearby tools

A practical method is to mark twenty or fifty stitches, unravel that run, measure the yarn in yards or metres, and divide by the stitch count of the run. Prefer sending numbers rather than pre-formatted strings when you control the client; string numbers are accepted only when they match a strict finite numeric pattern. Prefer this capability when you already know how many stitches the piece contains and you measured or were given yarn per stitch at a known gauge. Measure yarn_per_stitch from a swatch knit, washed, and blocked the same way as the garment, at the same gauge you will use for the project. Keep that length unit for yarn_length and yarn_with_waste; keep gauge in stitches per the same width unit you would use to check a row (inches or centimetres). When teaching, pair examples: twenty-eight thousand stitches at five stitches per unit with two hundredths and five thousandths of a unit of yarn per stitch yields seven hundred units of raw yarn; the same piece with ten percent waste yields seven hundred seventy; and stitch_count zero demonstrates the hard invalid_input path on a non-positive count. This landing targets people searching for a knitting yarn yardage estimator, how much yarn they need from a stitch count, or yarn length from gauge and consumption per stitch. It is not a rectangular crochet estimator that starts from width and height, not a stitch-gauge-from-swatch calculator, not a cast-on planner, and not a substitute-skein counter that starts from a published yardage. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately set stitch_count to zero. Round-trip checks are easy: recompute stitch_count times yarn_per_stitch by hand and confirm it equals yarn_length within the same rounding, and confirm that gauge times yarn_per_stitch equals yarn_per_unit_width.