Yarn is dyed in batches. Each batch — a dye lot — is a single dyeing run in which a quantity of yarn is colored together in the same bath, with the same water, dye mix, temperature and time. Every skein from that batch gets the same lot number printed on the label, usually next to the color number. The next batch is dyed to the same recipe, but small differences in fiber, water chemistry and timing mean the color can come out slightly lighter, darker or warmer.
Why it matters
On the shelf, two lots of the same color may look identical. Knitted or crocheted next to each other in a large, flat piece of fabric — a blanket, the body of a sweater — even a small difference can show up as a visible line or band where you joined a new skein. The effect is most noticeable in:
- Solid and semi-solid colors, especially mid-tones and pastels.
- Natural fibers such as wool and cotton, which take dye less uniformly than acrylic.
- Hand-dyed yarns, where every pot is unique; many indie dyers do not even assign lot numbers, and skeins from the same pot can differ.
- Large, plain areas under strong light.
Some yarns are labeled "no dye lot". These are typically mass-produced acrylics dyed with tightly controlled processes, so different batches are close enough to mix. They are a sensible choice for big blankets that you may need to top up later.
Reading the label
A label usually has a color number (the shade, which never changes) and a lot number (the batch). They may be labeled "Col." / "Shade" and "Lot" / "Batch" / "Dye lot". When you buy, check that every skein in your basket has the same lot number, not just the same color. Online, you can ask the shop to send skeins from a single lot, and many do so automatically for multi-skein orders.
How much to buy
The best protection is buying enough of one lot at the start. Use the calculator to estimate the total yardage, then:
- Include a 10% safety margin in the estimate (the default).
- For large projects — blankets, sweaters, anything over five skeins — buy one extra skein on top of the rounded-up number.
- Keep the receipt and the extra skein's label until the project is finished. Many shops accept returns of unused, unwound skeins.
- If the shop does not have enough of one lot, buy what they have of one lot and plan the design around a second lot from the start (see below), rather than discovering the shortfall halfway through.
An extra skein is not wasted: it is your repair kit for snags, moth damage or a missing button loop years later, and it matches perfectly.
When you have to mix lots
Sometimes there is no way around it — you underestimated, the yarn was discontinued, or you are using stash. These techniques hide a lot change:
- Alternate rows. For the last few inches before the new lot, and the first few after it, work two rows with the old lot and two rows with the new. In the round, alternate every round. The colors blend and the line disappears.
- Change at a natural break. Start the new lot at a stripe, the border, the yoke, the sleeves or the ribbing — places where a slight shift looks intentional.
- Use the new lot for separate pieces. Sleeves, collars, pockets and squares in a motif blanket can come from a different lot without anyone noticing, as long as they are not right next to identical fabric.
- Design with it. Gradients, stripes and color blocks turn two lots into a feature. For a granny-square blanket, mix squares from both lots randomly.
Always check the two lots side by side in daylight before deciding. Some differences only show in daylight; others look worse under warm indoor light.
Estimating per color
For multicolor projects, run the estimate for each color's share of the area. If a blanket has three colors in equal stripes, each color needs a third of the total yardage — then round each up to whole skeins separately. A small accent color still needs a whole skein. For colorwork graphs and C2C blankets, count the blocks or stitches of each color; the C2C graph maker on Feeed does this automatically.
Quick dye-lot rules
- Same color number and same lot number on every skein.
- Estimate + 10%, then round up, then one extra skein for big projects.
- No dye lot yarns are safest when you might need to top up later.
- Mixing lots? Alternate rows over a few inches, or change at a design break.
- Hand-dyed? Alternate skeins every two rows for the whole project.
Knowing the yardage before you buy is the simplest way to avoid dye-lot trouble. The yarn calculator rounds up to whole skeins for your label and reminds you to buy from one lot.