Instant Pattern Math • 100% Free
Calculators & Visual Guides for Knitters and Crocheters
Instant fiber craft calculators for the math every maker runs into—gauge swatching, yarn yardage, raglan shaping, stash project matching, and colorwork planning. Everything runs in your browser with zero signup and instant 1-page printable project cards.
Interactive Highlights
Featured & Visual Planners
Our most popular visual planners, stash matchers, and garment rate calculators.
Temperature Blanket Planner
Enter your region's annual low and high temperatures and how many colors you want to use. The planner divides your temperature span into even color brackets and estimates how many rows and skeins you will need for each shade.
Stash-Buster Project Matcher
Enter your yarn weight and available yardage, meters, or grams to instantly see every viable knitting and crochet project that fits comfortably within your stash budget with built-in safety margins.
Colorwork Contrast & Luminance Checker
Pick or paste your yarn colors to calculate their grayscale relative luminance and contrast ratio. The tool simulates how your motif pattern will look in black and white, confirming whether stitch details will stay crisp or blur together.
Top-Down Raglan Yoke Calculator
Enter your gauge, desired chest size, neckline circumference, and yoke depth to generate your customized neck cast-on breakdown, step-by-step raglan increase sequence, and underarm split counts.
Ribbing & Brioche Negative-Ease Calculator
Enter your target body circumference and relaxed stitch gauge to compute the ideal negative-ease cast-on count for 1x1 ribbing, 2x2 ribbing, or brioche stitch without bagging or sagging.
Flat Circle Crochet Calculator
Select your crochet stitch type (single, half double, or double crochet) and desired rounds or diameter. The calculator outputs the exact increase formula for every round, preventing cupping, ruffling, and hexagonal corners.
Visual Reference Library
Infographics & Cheat Sheets
Standard Blanket Sizing & Yardage Matrix
Visual scale comparison of 8 blanket sizes with yardage charts across DK, Worsted, Bulky, and Super Bulky.
InfographicMulti-Strand Yarn Equivalency & Holding Math
Combine lighter strands to hit heavier pattern gauges with exact inverse length math formulas.
Silhouette GuideHow Sweater Ease & Sizing Math Works
Concentric visual silhouette contours from negative ease to relaxed drop-shoulder and boyfriend fits.
ES / FR / PTMultilingual Craft Translation Glossaries
Side-by-side English to Spanish, French, and Portuguese term translations with abbreviation keys.
Complete Collection
All 26 Interactive Calculators
Cast-On & Elastic Sizing
Hat cast-ons, ribbing negative ease, blankets, and stitch multiple repeats.
- Blanket Cast-On CalculatorChoose a blanket size, enter your gauge, and get the cast-on stitches or starting chain count for a knit or crochet blanket.
- Hat Cast-On CalculatorEnter your head circumference and gauge, and this calculator gives you a cast-on stitch count with the standard negative ease knit hats need to fit snugly.
- Ribbing & Brioche Negative-Ease CalculatorEnter your target body circumference and relaxed stitch gauge to compute the ideal negative-ease cast-on count for 1x1 ribbing, 2x2 ribbing, or brioche stitch without bagging or sagging.
- Scarf Cast-On CalculatorEnter your scarf width and gauge to estimate how many stitches to cast on, with optional stitch-multiple rounding for textured patterns.
- Sock CalculatorEnter foot circumference and sock gauge to estimate cast-on stitches, heel stitches, instep stitches, and where to begin toe shaping.
Colorwork & Planning
Temperature blankets, organic stripe generators, contrast luminance, and time estimation.
- C2C Blanket CalculatorEnter your desired blanket size and C2C block gauge to calculate blocks wide, blocks tall, diagonal rows, and optional yarn estimate.
- Colorwork Contrast & Luminance CheckerPick or paste your yarn colors to calculate their grayscale relative luminance and contrast ratio. The tool simulates how your motif pattern will look in black and white, confirming whether stitch details will stay crisp or blur together.
- Granny Square Blanket CalculatorEnter your blanket size and granny square size to calculate the square layout, total number of squares, finished dimensions, and optional yarn estimate.
- Project Time EstimatorEstimate how many hours and calendar weeks a knitting or crochet project may take from total stitches, pace, and weekly crafting time.
- Stripe Pattern GeneratorEnter colors and row count to generate an even, random, or gradient stripe sequence with a visual preview and row counts.
- Temperature Blanket PlannerEnter your region's annual low and high temperatures and how many colors you want to use. The planner divides your temperature span into even color brackets and estimates how many rows and skeins you will need for each shade.
Garments & Shaping
Raglan yokes, sweater ease, sleeve tapers, and sock heel/toe math.
- Flat Circle Crochet CalculatorSelect your crochet stitch type (single, half double, or double crochet) and desired rounds or diameter. The calculator outputs the exact increase formula for every round, preventing cupping, ruffling, and hexagonal corners.
- Increase/Decrease Evenly CalculatorEnter your current stitch count and your target stitch count, and this calculator spaces the increases or decreases evenly across the row and gives you the exact repeat instruction.
- Top-Down Raglan Yoke CalculatorEnter your gauge, desired chest size, neckline circumference, and yoke depth to generate your customized neck cast-on breakdown, step-by-step raglan increase sequence, and underarm split counts.
- Sleeve Shaping CalculatorEnter upper-arm and wrist measurements plus gauge to calculate sleeve decrease rows and shaping intervals.
- Sweater CalculatorEstimate sweater body stitch counts, front/back panel counts, body rows, armhole rows, and sleeve opening stitches from measurements and gauge.
Measurement & Gauge
Swatching math, stitch and row gauge calculations, and pattern resizing.
- Gauge CalculatorKnit or crochet a swatch, count your stitches and rows over a measured area, and this calculator converts that into stitches and rows per inch, per 4 inches, and per 10cm so you can compare it directly to a pattern's stated gauge.
- Pattern Gauge Adjustment CalculatorEnter the pattern gauge and your actual gauge to scale stitch and row counts for a different gauge.
- Stitch Multiple CalculatorEnter your gauge, target width, and the pattern's stated stitch multiple (like "multiple of 4 + 2") to get the exact cast-on count and the nearest valid counts above and below it.
Conversions & Reference
US/UK/Metric needle and hook charts, WPI weight conversion, and metric calculators.
- Held-Together Yarn CalculatorChoose two yarn weights to estimate the effective yarn weight, approximate WPI, and suggested needle or hook range when yarns are held together.
- Needle & Hook Size ConverterEnter a US, UK/Canadian, or metric (mm) knitting needle or crochet hook size and get the equivalent sizes in the other two systems.
- WPI (Wraps Per Inch) to Yarn Weight ConverterWrap your mystery yarn around a ruler for exactly one inch, count the wraps, and enter that number here to get its yarn weight category and a suggested needle or hook size range.
Yarn & Stash Management
Yardage estimates, stash-busting project matching, and held-together strand math.
- Stash-Buster Project MatcherEnter your yarn weight and available yardage, meters, or grams to instantly see every viable knitting and crochet project that fits comfortably within your stash budget with built-in safety margins.
- Yarn Stash / Remaining Yarn CalculatorWeigh your partial skein, enter the full skein's weight and yardage from the label, and this calculator estimates how much yardage is actually left.
- Yarn Substitution CalculatorCompare original and substitute yarn yardage to estimate how many substitute skeins you need and whether the yarn density looks close.
- Yarn Yardage CalculatorEnter your project's width and height, yarn weight, and stitch type, and this calculator estimates total yardage needed (plus a safety buffer) and how many skeins to buy.