Book Review: Math for Knitters by Kate Atherley
Kate Atherley's Math for Knitters was first announced in August 2025 with a release date in October that year. The first run sold out in the blink of an eye and even after that it's proved exceedingly difficult to get a hold of. One day it was available for order; the next day my order was canceled. This went on for a while but I've now finally been able to not only get the book but to read and review it.
In this blog post you'll learn what Math for Knitters is all about, who it's intended for, my thoughts on what's good about the book, and where it could've been improved upon.
Who Is This Book for?
In the introduction, Kate Atherley writes that this book is aimed for knitters of all levels. I'll come back to the "all levels" aspect a little later but the keyword here is "knitters". This is not a design book — it won't help you write knitting patterns or grade them to multiple sizes — nor is it intended for people who like to freehand things and come up with custom items.
Instead, Math for Knitters is written for ordinary knitters working from a knitting pattern who need help either in interpreting what it says or adjusting it to fit their needs. The math in the book is accessible to anyone — the calculations are not particularly difficult — but I'd say the first two thirds of the book are geared for beginning and less-experienced knitters. The later chapters on pattern adjustment are more suited for those who are more advanced in their skills, want to fine tune the fit of existing patterns, and are willing to go through the calculations to get there.
Four Types of Math
Atherley divides the types of calculations a knitter would typically need to make into four categories: yarn shop math, gauge math, pattern reading math, and garment math. The book itself is divided into nine chapters (see above), with one or more chapters dedicated to each of these math types.
Yarn Shop Math
Chapter 1 is the shortest of all the chapters and it covers yarn shop math. In this section, you'll learn how to do yarn substitutions and calculate (or estimate) how much yarn you have left in a partial ball.
Say, for instance, that you want to knit a pattern that calls for five balls of Yarn A that comes in 200 m/100 g. You want to substitute it with Yarn B with 175 m per 50-gram balls instead. How many balls do you need to buy?
While the book will tell you the mathematical formula for calculating this (and you probably already figured it out), it doesn't take into account whether Yarn B is a suitable replacement in the first place. Yarn substitution is not just about comparing yardages — that would be far too simple. Yarn weight (thickness), fiber composition, and ply structure also come into play, and the book glosses over all of them.
Pattern Reading Math
I'm skipping the second chapter for now and delving into Chapters 3–5 on pattern reading math. In these chapters you'll learn how to interpret knitting pattern instructions in certain mathy situations.
Chapter 3 deals with different ways repeats are expressed in knitting patterns, both in stitches and in rows. And there are lots! My favorite post to refer to on this topic is Interweave's Ask The Experts: Can You Repeat That?
This chapter also covers that tricky situation when the pattern says to repeat something "X times", "X more times", or "X times total". Do they mean the same thing or not? How do you look for clues in the pattern that'll tell you which way is the right way?
Another pattern-reading conundrum that pops up time and time again is decreasing or increasing "every 10th row", for instance. Do you de/increase first or work even first? How many rows do you knit between de/increases? And what does "work even" even mean? Atherley will tell you the answers to all these with clear examples.
Chapter 4 is all about the math of evenly. When a pattern says, for example, to "increase 10 sts evenly across the next row", it can stump a lot of knitters. The pattern tells you the end goal but not the steps how to get there. While there are lots of decrease/increase evenly calculators on the internet, this chapter and the math Atherley teaches here is worth paying attention to. It's the basis of all shaping-rate calculations you'll need when modifying patterns in Chapters 6 through 9.
Chapter 5 is dedicated to a special case: spacing out buttonholes evenly (there's that word again!) on a button band. This topic gets its own chapter because the act of binding off can mess up your thinking a bit. As I always like to say it: in order to bind off X stitches, you need to work X+1 stitches.
Gauge Math
Gauge math is handled in two separate(d) chapters: Chapters 2 and 6. Dividing these chapters far apart is quite an odd choice as far as the book structure is concerned. It would've made more sense to keep them together because the information in Chapter 2 leads into Chapter 6.
Chapter 2 discusses what gauge means and it's dual purpose in knitting: as a proxy for yarn thickness (weight) and as a tool for ensuring that your knitted object comes out the size it's intended to. This chapter is less about math and more about on how to knit a gauge swatch, something I've covered in this blog post: 6 Common Misconceptions about Gauge Swatches.
Atherley instructs you on how to pick a needle size, how many stitches to cast on, how much and what stitch pattern to knit, how to block your swatch, and how to measure your gauge. More importantly, it also tells you what to do with the results you get. What if you obtain gauge on the first try? Congrats, you're a magical unicorn. What it you're close… but not quite there? Or the worst situation of them all (or is it?): what to do if you get stitch gauge but not row gauge?
This chapter also has what I thought was the most surprising bit in the entire book. Atherley is quite adamant in that you should not compensate for differences in gauge by knitting a smaller or larger size in the pattern.
To some degree, I agree with the advice but wouldn't be quite so absolute in damning this practice. Knitters do this all the time! I've done it myself, and with successful results. If you're close-but-not-quite-there in gauge (within 10% or so), deviating one or at most two sizes from your "real" size is often the easiest way to modify the pattern… provided you're not jumping between grading blocks. But the further you get from the original size, the bigger the chances that some parts of the garment will get distorted. Or, as Atherley (p. 30) puts it: "The widths might work, but that doesn't mean that other things will."
Jumping to Chapter 6, this chapter covers how to convert a pattern to work at a different gauge. It doesn't mean to take pattern instructions as-is and just work them at a different gauge. Instead, this means taking each stitch and row count in the pattern, converting them back to lengths, and re-calculating those lengths in the new stitch and row gauges.
As you can imagine, the more complex the structure of the pattern and the more shaping it involves, the more calculations you need to do. It's relatively straightforward to convert a rectangular scarf from fingering to worsted. But doing the same on a seamed set-in sleeve sweater? It's akin to basically designing from scratch.
Garment Math
The last three chapters of the book have to do with modifying knitting patterns to better fit your preferences or body measurements.
Chapter 7 discusses size, fit, and ease. It details different ways how size can be expressed in knitting patterns, be it in ages (often seen in baby or children's patterns), letters (S, M, L...), numbers (1, 2, 3…), or chest circumferences (36, 38, 40…). On their own, these naming conventions are meaningless. Next, the chapter discusses how and what measurements are given in knitting patterns, and how to interpret pattern schematics. Finally, the pattern delves into the concept of ease and how patterns might express fit recommendations. Putting those three things together you get the answer to the question: which pattern size should I choose?
One thing that delighted me in this chapter is the advice to pick a size based on upper-bust circumference, and how that leads to better-fitting garments. And this recommendation doesn't apply only to busty people; it's for everyone. Ditch the full bust!
Thus far the book has been filled with information that knitters of all levels can absorb. The remaining two chapters are geared towards more experienced knitters and, unfortunately, this is where it starts to fall apart.
Chapters 8 and 9 cover garment alterations, that is, how to modify a pattern to better suit your needs. But there's quite a big limitation to the types of modifications the book walks you through: they only apply from the underarm down. That is, you can only modify body length and shaping or sleeve length and shaping, but anything that would involve adjusting the fit of the upper body is ruled out. There is no advice on how to do bust shaping. And I think this is a bit of a cop out.
Garment alterations are categorized into three difficulty groups. For example, adjusting body length on a sweater with no shaping is easy whereas adding (or adjusting) waist shaping is a bit more complex.
Here we run into another odd choice in the book structure. Chapter 8 details these different types of pattern modifications only on the conceptual level. It tells you which things to measure, which things to decide, and which things to calculate… but doesn't show how to transform that information into actual stitch or row counts. Chapter 9 has all calculations needed for these modifications which leads to unnecessary flipping back and forth to find the right page.
And there are no examples in this part of the book. Chapters 8 and 9 read like a dense college textbook that's all theory, theory, theory. I get that including fictional examples of each of the 14 (yes, I counted) alteration types would've made the chapter exceedingly long but it also would've made it so much more informative. Now the knitter is left to their own devices to parse out the necessary steps to take with no assurance of whether they're going even in the ballpark of a right direction.
The Good, the Bad, and the Ugly
While the contents of the Math for Knitters are rock solid (save for the last two chapters), what I wasn't as keen on was how the information was presented. There are odd typographical choices, like using tons of different font types, which make reading the book a bit disjointed. There are sidebars within the body of the text which would've been better presented, well, in a sidebar on the side of the page. There are references to illustrations "on the right" when in fact said illustration is located on the next page.
The entire book has a very textbook feel which can make it a bit tiresome to read. While there are some black-and-white line drawings, the layout could've been livened up. I'm not saying cutesy Franklin Habit-style cartoons a la Patty Lyons' Knitting Bag of Tricks but something to break up the dense text would've helped a lot. The Knitting Pattern Writing Handbook by Kristina McGrath & Sarah Walworth is also done without color photos, yet reading it is a joy because of a clear layout, consistent font use, and grayscale drawings to illustrate what's being discussed.
All in all, Math for Knitters feels a bit self-publish-y, unfinished, as if an editor hasn't given it a final look. Or even a first look.
Final Verdict
Math for Knitters is a great reference book to knitters who need a little refresher on how to interpret certain tricky instructions in knitting patterns, (re)calculate shaping rates, or do simple pattern modifications. Especially learning how to increase and decrease evenly without the help of online calculators will provide a solid basis for many math problems you might encounter when working from and adjusting knitting patterns.
If you're looking for help with more complex pattern alterations or custom-fit garments, this is not the right book for you. But fear not: where Math for Knitters falls short, Kim McBrien Evans' The Knitter's Sweater Fitting Bible picks up. It discusses both upper and lower body adjustments, including bust darts, and presents everything with clear examples, illustrations, and full-color photos. And I'll be reviewing that next.
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