Why Estimating Yardage Is Harder Than It Looks
Here's the frustrating thing about yarn. Two projects that look the same size can use wildly different amounts of yarn depending on the stitch pattern, your tension, the hook or needle size, and the yarn weight.
A single crochet blanket uses way more yarn than a double crochet blanket of the same dimensions. A lace pattern uses less than a cable pattern. And if you're a tight crocheter, you'll use less than someone who works loose.
So when people ask "how much yarn do I need for a blanket," the honest answer is: it depends. But I can give you solid starting points and a method to calculate it accurately for your specific project.
The Swatch Method: Most Accurate Approach
If you want accuracy, make a swatch. I know, I know. Nobody wants to make a swatch. But it saves you from running out of yarn three rows from the end of a blanket.
Here's how.
Step 1: Make a 6 × 6 inch swatch using the exact stitch, yarn, and hook or needle you plan to use for the project.
Step 2: Count how many yards of yarn you used. You can do this by weighing the swatch and comparing it to the full skein weight, or by measuring the length you pulled off before starting.
Step 3: Calculate yards per square inch. If your 36 square inch swatch used 18 yards, that's 0.5 yards per square inch.
Step 4: Calculate your project's total area. A 50 × 60 inch blanket is 3,000 square inches.
Step 5: Multiply. 3,000 × 0.5 = 1,500 yards.
Step 6: Add 10 to 15% buffer. 1,500 × 1.15 = 1,725 yards.
Step 7: Divide by yards per skein. If each skein has 200 yards: 1,725 ÷ 200 = 8.6. Round up to 9 skeins.
General Yardage Estimates by Project Type
If you don't want to swatch, here are ballpark numbers for worsted weight yarn. Adjust up for heavier yarns and down for lighter ones.
Baby blanket (30 × 40 inches): 800 to 1,200 yards Throw blanket (50 × 60 inches): 1,500 to 2,500 yards Twin blanket (70 × 90 inches): 3,000 to 4,000 yards Queen blanket (90 × 95 inches): 4,000 to 5,000 yards
Adult sweater: 1,200 to 2,000 yards Child sweater: 600 to 1,000 yards
Scarf (6 × 60 inches): 300 to 500 yards Hat: 150 to 250 yards Socks (pair): 350 to 450 yards Amigurumi (small): 100 to 200 yards
These are for crochet. Knitting typically uses 25 to 30% less yarn for the same size project because knitted fabric is thinner and less dense than crocheted fabric.
How Yarn Weight Changes the Math
Thicker yarn means fewer yards but more weight. Thinner yarn means more yards but less weight.
Here's a rough comparison for a 50 × 60 inch throw blanket:
Lace weight: 2,500 to 3,500 yards Fingering: 2,000 to 2,800 yards DK: 1,800 to 2,400 yards Worsted: 1,500 to 2,200 yards Bulky: 1,200 to 1,800 yards Super bulky: 800 to 1,400 yards Jumbo: 500 to 900 yards
Notice how the range narrows as yarn gets thicker. That's because there are fewer stitch pattern variations at the bulky end.
When substituting yarn, don't just match the weight. Check the yardage per gram. Two "worsted" yarns might have very different yardages depending on fiber density.
The Dreaded Dye Lot Problem
Buy all your yarn at once. I mean it. Buy every skein you need plus one extra, and buy them in the same shopping trip.
Dye lots vary. Even the same color from the same brand can look slightly different between production runs. With a large project like a blanket, a dye lot switch in the middle will be visible. It might look fine in the store, but once the project is done and you see it in natural light, that subtle shift will drive you crazy.
The extra skein is your insurance policy. If you finish with yarn left over, you can always return it (most yarn shops are good about this) or save it for repairs. But if you run out and can't get the same dye lot, you're stuck.