Fiber arts calculators for confident projects
Last updated: August 22, 2026
Calculate materials, correct gauge and stitch counts, or plan a knitting or crochet project with practical tools that show their work.
All self-service calculators stay free. Optional professional reviews and project downloads are paid.
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What do you need to solve?
Calculate yarn and materials
Estimate yardage, compare yarn information, and prepare a realistic supply list.
Start with the Yarn Calculator →📐Fix gauge, sizing, and stitch counts
Turn a measured swatch into the stitch and row counts your project needs.
Start with the Gauge Calculator →🗂️Plan a crochet or knitting project
Move from an idea to workable dimensions, quantities, and construction decisions.
Start planning a project →Start here
Featured calculators
Five calculators to help size projects, estimate materials, and work through construction math.
Blanket Calculator
Calculate blanket stitch counts and estimate yarn from a measured swatch for sizes from baby to king.
Yarn Calculator
Scale yarn measured in a representative swatch to a flat rectangular target, then convert the planning total to whole skeins.
Circle Planner
Generate a basic staggered-increase circle schedule from a selected stitch preset and round limit; swatch and adjust for the material and stitch.
Amigurumi Shapes
Generate bounded arithmetic round schedules for basic sphere, cone, cylinder, and oval starting shapes; verify technique and counts before use.
Cast On Calc
Calculate a rounded cast-on count for an entered width and gauge, with optional pattern-multiple and edge-stitch adjustments.
Also featured
Sock Calculator
Calculate a bounded circular stitch-count checkpoint from entered foot circumference, ease, measured gauge, and stitch multiple.
Complete directory
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Search the remaining free self-service tools by the project problem you need to solve.
Showing 28 tools
Needle Converter
Look up entries in the included knitting-needle and crochet-hook size tables; confirm metric diameter and current manufacturer labeling.
Gauge Calculator
Calculate measured gauge and proportionally scale entered stitch or row counts; pattern repeats, shaping, and fit still need separate review.
Yarn Weights
Yarn weight reference with common US, UK, and Australian names, knitting gauge guidelines, and a swatch-first label comparison.
Fabric Substitutes
Compare 30 garment fabrics by construction, stretch, weight, drape, structure, opacity, and recovery, or find projects suited to fabric you already own.
Stitch Counter
Track up to six named counts and set exact-count reminders on the first counter. Browser-local saving is attempted but not guaranteed.
Pattern Checker
Check crochet round math line by line. See stitches consumed, stitches created, written totals, and possible errors.
Inc/Dec Calculator
Build a bounded stitch-by-stitch plan for distributing an entered increase or decrease across one row or round.
Stripe Generator
Generate a bounded random, weighted, or repeating stripe-row sequence from the colors and row limits you enter.
Abbreviations
Search the included knitting and crochet abbreviations with US/UK references and selected step-by-step notes.
Spinning Calculator
Calculate the simplified geometric ratio between entered effective drive-wheel and connected-pulley band-path diameters.
Stitch Calculator
Find bounded stitch counts compatible with the entered pattern multiples and plan a supported sampler layout.
Stitch Reference
Visual step-by-step reference for the included common stitches, with yarn overs, pull-throughs, loop counts, and turning-chain notes.
Cross Stitch Calc
Calculate dimensions for an entered stitch count and supported fabric count, with a planning estimate for stranded-cotton use.
Sett Calculator
Calculate a starting sett and warp worksheet from entered WPI and show only supported reed-sleying options; sample the cloth before committing.
Cost Calculator
Total the yarn, notions, and extras you enter, with an optional stitch-rate time estimate and selling-price scenario.
Color Pooling
Preview how an entered repeating color-run sequence maps across a chosen stitch count; swatching is still required.
Thread Converter
Look up exact entries in the included DMC, Anchor, and Cosmo embroidery-thread table.
UK/US Converter
Replace supported modern UK and US crochet terms in pasted text using a one-pass mapping; all other text is left unchanged.
Needle Guide
Compare the included needle types, then verify the choice for the specific material and task.
WPI Calculator
Enter your wraps per inch and instantly identify yarn weight, recommended needles and hooks, gauge range, and suggested projects.
C2C Calculator
Round entered dimensions to a bounded nominal C2C grid from a two-axis swatch, with optional measured yarn-per-block planning arithmetic.
Hat Calculator
Calculate a rounded cast-on count and bounded eight-section crown schedule from the entered head measurement, ease, and gauge.
Granny Planner
Plan a nominal granny-square grid, square count, equal-share color average, and unique internal seam length from entered dimensions.
Sleeve Calculator
Plan a bounded paired-decrease sleeve taper from entered measurements and gauge; unsupported odd or over-dense schedules are declined.
Raglan Checkpoint
Calculate one bounded finished-body stitch checkpoint from entered circumference, measured gauge, and stitch multiple.
Blocking Calc
Calculate the signed percentage change between current and requested project dimensions.
Stash Estimator
Estimate remaining yardage in partial skeins by weight, plus a yardage reference table for unlabeled yarn by weight category.
Pattern Decoder
Translate vintage and UK knitting and crochet patterns into modern US terminology. Converts UK-to-US stitch names, archaic abbreviations, and flags era-specific measurements.
Fiber Arts Guides & Tutorials
View all →The Complete Guide to Reading Yarn Labels (What Every Number Means)
Learn how to read yarn labels like a pro! This comprehensive guide explains yarn weight symbols, washing care instructions, gauge information, and what every number on your yarn label actually means.
Knitting Gauge: Why It Matters and How to Get It Right
Learn what knitting gauge measures, how to prepare a representative swatch, and how to review stitch and row differences without treating one count as a full pattern regrade.
How Much Yarn Do You Need for a Blanket?
Plan blanket yarn from representative measurements and understand how size, yarn, stitch pattern, and allowance affect an estimate; no calculator can guarantee a purchase quantity.
Knitting Needle Sizes: US, UK, and Metric Explained
Understand the three knitting needle sizing systems, US, UK, and metric, their history, how to convert between them, and how to identify unlabeled needles.
UK vs US Crochet Terms: Key Conversion Guide
Understand why UK and US crochet terminology differs, learn the key conversions like double crochet and treble, and discover how to identify which system a pattern uses.
What is WPI (Wraps Per Inch) and How to Measure It
Learn what Wraps Per Inch measures, how to wrap yarn correctly, WPI ranges for every yarn weight, and how to use WPI for yarn substitution and handspun identification.
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Buying guides
Compare yarn, hooks, and needles after your calculations are complete. Destination pages clearly disclose paid links.
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Read the newsletter promise →Fiber Arts Fundamentals
Reference answers for knitting, crochet, weaving, and yarn selection, connected directly to the calculators that use them.
How do fiber arts calculators work?
Enter your gauge swatch measurements, yarn weight, or pattern details, the calculator applies standard fiber arts formulas to give you instant, accurate results.
FiberTools calculators use CYC yarn weight standards, gauge mathematics, and pattern conversion formulas validated against industry references. Each tool processes your inputs entirely in the browser, so results are instant and your data never leaves your device.
Whether you are scaling a pattern to a different size, converting between US and metric needle sizes, or estimating yardage for a substitution, the underlying formulas account for stitch ratio, row gauge, and fiber-specific variables.
Treat every calculator result as a planning aid: follow the pattern and yarn label, make a representative swatch, and verify fit or dimensions before committing the full project.
Why does gauge matter in knitting and crochet?
Gauge determines the final size of your project. Even one stitch per inch off gauge can make a garment several sizes too large or too small over 200 rows.
Gauge varies by knitter tension, needle material, yarn fiber content, and stitch pattern, two crafters using the same yarn and hook size can produce swatches that differ by a full stitch per inch. This is why pattern designers specify gauge over a 4-inch swatch, not just a single repeat.
A gauge swatch helps reveal sizing problems before you commit yarn and time to a fitted project.
Washing and blocking can change a swatch's dimensions, especially with natural fibers. Measure after treating the swatch the same way you will treat the finished item, and swatch in the round when the pattern is worked in the round.
What are CYC yarn weight standards?
The Craft Yarn Council (CYC) defines 8 standard yarn weights: Lace (0), Fingering (1), Sport (2), DK (3), Worsted (4), Bulky (5), Super Bulky (6), and Jumbo (7).
CYC standards help crafters substitute yarns reliably across patterns from different designers and countries. Each weight category specifies a gauge range in stitches per 4 inches and a recommended needle or hook size, giving you a consistent baseline regardless of brand or fiber content.
Using the correct weight category is the first step in any successful yarn substitution. From there, a gauge swatch confirms whether the specific yarn within that category matches your pattern's tension requirements.
What is the difference between knitting and crochet needle sizing?
Knitting uses needle sizes in US numbers (1–50) or metric millimeters. Crochet uses hook sizes in US letters (B/1 through S/35) or metric millimeters, which is the most universal sizing system.
Metric millimeter sizing is recommended for precision since US letter and number systems vary by manufacturer, a US size G hook from one brand may measure 4.0mm while another measures 4.25mm. Patterns that specify metric sizes are unambiguous and easier to match when substituting tools.
Further Reading
- Craft Yarn Council yarn weight standards , Official CYC weight classifications and gauge ranges.
- Ravelry gauge and needle size guide , Community reference for gauge, needle sizing, and yarn substitution.
- Craft Yarn Council yarn and gauge questions , Guidance on gauge, yarn weights, and yarn substitutions.
About FiberTools
FiberTools is a collection of free self-service calculators and references for practical planning problems such as yarn quantities, gauge, size conversion, and row tracking.
The tools are grounded in industry standards. Yarn weight classifications follow the Craft Yarn Council CYC system, needle and hook sizing follows US, metric, and UK conventions, and calculation methods remain visible so you can check the assumptions.
All self-service calculators stay free. Optional professional reviews and project downloads are paid.
Calculator inputs and results stay in your browser. FiberTools does not require an account to use the calculators, and many tools work offline once loaded.
Frequently Asked Questions
What is a yarn weight calculator?
A yarn weight calculator helps knitters and crocheters determine the correct yarn weight for a pattern or substitute yarn. Enter your gauge swatch measurements and the tool identifies whether your yarn is lace, fingering, sport, DK, worsted, bulky, super bulky, or jumbo weight using CYC standard classifications.
How do I calculate gauge for a knitting or crochet pattern?
Knit or crochet a 6-inch swatch in your chosen stitch pattern, then count the stitches and rows within a 4-inch section. Enter those numbers into the gauge calculator to see if your tension matches the pattern. Adjust needle or hook size if your gauge is off, too many stitches means go up a size, too few means go down.
What is the difference between US and UK crochet terminology?
US and UK crochet terms use the same names for different stitches. A US single crochet equals a UK double crochet, a US double crochet equals a UK treble crochet, and so on. Always check whether a pattern uses US or UK terminology before starting to avoid working the wrong stitches.
How do I substitute yarn in a knitting pattern?
Match the yarn weight category first, then check that your gauge swatch with the substitute yarn matches the pattern gauge. Weight alone is not enough, fiber content affects drape and stitch definition, so swatch before committing to a full project. FiberTools calculators help you verify gauge and yardage requirements for substitutions.
What yarn weight should beginners start with?
Worsted weight (CYC 4) is the best starting yarn weight for beginners. It is thick enough to see individual stitches clearly, works up quickly, and is widely available. Pair it with a US size 7–9 knitting needle or a 5mm crochet hook for most beginner patterns.
How do I read a crochet pattern as a beginner?
Start by identifying whether the pattern uses US or UK crochet terminology. Then read the entire pattern before you start, noting the yarn weight, hook size, gauge, finished measurements, and abbreviations used. Work in sections, checking your stitch count at the end of each row or round against the pattern's count.
What is blocking in knitting and crochet?
Finishing or laundering can change a project's dimensions and appearance. Follow the pattern and product care instructions, then test the intended treatment on a representative swatch; there is no universal growth percentage for a fiber category.
What is amigurumi and what yarn do I use?
Amigurumi is the Japanese art of crocheting small stuffed animals and characters using single crochet worked in a continuous spiral. Use worsted weight (CYC 4) or DK weight (CYC 3) yarn with a hook one to two sizes smaller than the yarn label recommends. The tighter fabric prevents stuffing from showing through the stitch gaps.
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