How to Measure a Dog for a Harness (Girth, Neck, Width)
To measure a dog for a harness, stand the dog and wrap a soft tape around the rib cage just behind the front legs, at its widest point. That chest girth sizes every harness chart on this site. Kurgo's chart also asks for the neck, and PetSafe's for the chest width, and those decide between sizes when the girth fits more than one. How tight to pull the tape is where the published methods disagree, so the steps below follow each maker's own wording.
Chest girth: the measurement every chart uses
AKC describes chest girth as the measurement "around the largest part of your dog's rib cage, usually just behind the front legs". Ruffwear puts it at "the widest part of your dog's chest just behind the front legs", and PetSafe has you wrap the tape "around the deepest part of your dog's rib cage behind his front legs". All three mean the same ring of the body, and AKC and PetSafe both say to measure the dog standing ("Measure your dog while they are standing so their spine is aligned"). Ruffwear's tool advice: "use tailor's tape — or if you don't have tailor's tape, you can use a long string and measure it later." Mark the string where it meets and lay it against a ruler.
Take two readings. If they differ, measure again with the dog standing, as AKC and PetSafe ask.
How tight: tight to the skin, or two fingers under
This is the one step the sources do not agree on:
| Source | What to measure | What it says about tape tension or fit |
|---|---|---|
| AKC | Chest girth and neck girth | "Keep the tape snug but not tight, and follow the two-finger rule to ensure a comfortable fit." |
| Ruffwear | Girth only | Nothing on tension |
| Kurgo | Neck (A) and chest (B) | "The fit should be snug but not restrictive." |
| PetSafe | Chest width and girth | "try to keep the measuring tape tight and as close to skin as possible." |
PetSafe's instruction gives the body's own size; AKC's two-finger rule builds in the room the harness should leave, so the AKC tape reads larger on the same dog. Neither is wrong, but each maker's chart was written for its own method. Measure the way the maker of the harness you are buying says to, and if it says nothing about tape tension, as Ruffwear's harness guidance does not (Kurgo's line is about how the harness should fit, not the tape), write down both readings.
The second measurement: neck or chest width
Ruffwear sizes its harnesses on girth alone. Kurgo's Tru-Fit Smart Dog Walking Harness chart has a neck column and a chest column; the product page says "Measure chest and neck to determine harness size." The page labels the chart columns Neck (A) and Chest (B) but does not say in text where on the body each is taken; that is shown in a video. AKC describes neck girth as "the circumference of your dog's neck, generally where the collar sits."
PetSafe's Easy Walk chart adds chest width, measured across the front of the chest rather than around it: "Measure across your dog's chest, with the measuring tape tight to his body. Start about 1 inch behind his front leg and measure across the chest and ending about 1 inch behind the other front leg." That is a short measurement compared with girth: the PetSafe Easy Walk chart's widths run from 7 to 24 inches while its girths run from 12 to 49.
Why one girth fits several sizes
The charts overlap, and differently. Ruffwear's bands meet end to end, so a girth of exactly 13, 17, 22, 27 or 32 inches sits in two sizes. Kurgo's and PetSafe's bands overlap by several inches, which is why their charts carry the second measurement. The figure draws every band of the three charts on one axis; the highlighted bars are the sizes that cover a 27 inch girth.
Here is what each chart offers at Ruffwear's three largest boundaries, with the second measurement that separates the candidates:
22 inch girth. Ruffwear: XS (17–22 in) or S (22–27 in). Kurgo Tru-Fit: Small (neck 12–20 in) or Medium (neck 16–25 in). PetSafe Easy Walk: Small/Medium (chest width 11–13 in) or Medium (chest width 12–15 in).
27 inch girth. Ruffwear: S (22–27 in) or M (27–32 in). Kurgo Tru-Fit: Medium (neck 16–25 in) or Large (neck 18–30 in). PetSafe Easy Walk: Medium (chest width 12–15 in) or Medium/Large (chest width 14–18 in) or Large (chest width 16–21 in).
32 inch girth. Ruffwear: M (27–32 in) or L/XL (32–42 in). Kurgo Tru-Fit: Large (neck 18–30 in) or X-Large (neck 24–35 in). PetSafe Easy Walk: Medium (chest width 12–15 in) or Medium/Large (chest width 14–18 in) or Large (chest width 16–21 in) or Extra Large (chest width 17–24 in). The second measurement narrows the choice, but those columns overlap too: at 27 inches, a neck between 18 and 25 inches still fits both Kurgo sizes (Medium and Large). When two sizes remain, the maker's in-between rule applies.
Between sizes: each maker's rule
| Harness | Rule when the dog is between sizes |
|---|---|
| Ruffwear Front Range | "Choose the larger size." |
| Ruffwear Flagline | "Choose the larger size." |
| Ruffwear Web Master | "Choose the smaller size." |
| Ruffwear Hi & Light | "Choose the larger size." |
| PetSafe Easy Walk | "Choose the size that best includes both measurements. If your dog is between two sizes, choose the larger size or the size in which the girth measurement best matches." |
| Kurgo Tru-Fit | No rule on the product page |
The Web Master is the exception in Ruffwear's own range: it is the one model whose page says to size down. Ruffwear's general size guide adds a rule for puppies: "If your growing pup is truly between two sizes, choose the larger size." AKC's advice when a dog falls between sizes is to look for a harness with enough adjustment to fine-tune the fit.
One more Ruffwear detail worth knowing before ordering: The size guide lists L 32–36 in and XL 36–42 in separately; the Front Range, Flagline, Web Master and Hi & Light product pages (the chart used on this site) list one L/XL size, 32–42 in.
Weight is a fallback, not a size
Ruffwear prints no dog weights on any of the four harness pages read for this site. Kurgo and PetSafe do, and PetSafe calls its weight column approximate: "Measuring your dog is the most accurate way to determine harness size. Weight ranges are only approximate. If your dog is between two sizes, choose a size up." The harness, crate and bed size by weight table shows those weight bands for anyone without a tape to hand, but a tape settles it.
Checklist
- Stand the dog on a level floor.
- Wrap a soft tape (or a string) around the rib cage just behind the front legs, at the widest point. Use the tension the harness maker asks for.
- If the chart has a neck or chest-width column, take that measurement too.
- Read the chart. If the girth fits two sizes, let the second measurement decide; if it still fits two, use the maker's in-between rule.
- Recheck a growing puppy's girth against the chart before each new harness.
The harness size chart turns a girth into a Ruffwear size and shows the same girth on every maker's chart; each chart also has its own page: Ruffwear, Kurgo Tru-Fit and PetSafe Easy Walk. For crates, the measurements are length and height instead: see how to measure a dog for a crate.
Sources
- American Kennel Club — How to measure your dog for gear (Courtney Campbell, updated Aug 10, 2026), read 2026-10-26.
- Ruffwear — Size guide, read 2026-10-26.
- Kurgo — Tru-Fit Smart Dog Walking Harness product page, read 2026-10-26.
- PetSafe support — How to measure your dog to determine which size Easy Walk harness is needed, read 2026-10-26.
- Ruffwear — product sizing charts (Front Range, Flagline, Web Master, Hi & Light), checked 2026-10-21.
- Kurgo — Tru-Fit Smart Dog Walking Harness size chart (manufacturer), checked 2026-10-21.
- PetSafe — Easy Walk Harness sizing chart (manufacturer, PetSafe UK product page), checked 2026-10-21.
Questions
Where do you measure a dog's chest for a harness?
Around the rib cage just behind the front legs, at its widest or deepest point, with the dog standing. AKC, Ruffwear and PetSafe all put the tape in that place; that circumference is the chest girth every harness chart starts from.
Should the tape be tight or loose?
It depends on whose chart you are reading. PetSafe asks for the tape tight and as close to the skin as possible; AKC says snug but not tight with two fingers under the tape. A tape with two fingers under it reads larger, so measure the way the maker of the harness you are buying says to.
Do I need a neck measurement?
Only for harnesses whose chart lists one. Ruffwear sizes on girth alone. Kurgo's Tru-Fit chart has a neck column next to chest, and PetSafe's Easy Walk chart has a chest-width column. When several sizes cover your dog's girth, that second measurement picks between them.
My dog is between two harness sizes. Which one?
Follow the maker's rule for that model. Ruffwear says choose the larger size for the Front Range, Flagline and Hi & Light but the smaller for the Web Master. PetSafe says choose the size that best includes both measurements, else the larger or the one whose girth matches best.
Can I size a harness by my dog's weight?
Only roughly. Ruffwear publishes no weights at all, and PetSafe calls its weight column approximate and says measuring is the most accurate way to choose. Two dogs of the same weight can be different sizes because chest shape varies.