Start with the size chart for the exact harness you are considering. A “medium” in one design may use different measurements from a medium in another, and a dog's weight alone does not describe their body shape.
The process has two parts: measure your dog to choose a size, then adjust the harness on your dog to check the fit. A measurement within a chart's range is a starting point, not the end of the fitting process.
1. Open the chart before picking up the tape
Read the product's measurement diagram and instructions. Does it ask for chest girth, neck circumference, body length, weight, or a combination? Check the units, too.
For example, Ruffwear's measuring guide uses the widest circumference of the chest for its harness sizing. Kurgo's fitting guide includes chest and lower-neck measurements and treats weight as supporting information. Follow the chosen model's requirements rather than borrowing a chart from another brand.
Save the chart with the product name. If the listing and packaging show different instructions, ask the seller or manufacturer to resolve that before ordering.
2. Prepare for a short measuring session
Use a flexible measuring tape and somewhere to record the results. Ruffwear also describes using a length of string, marking where it meets, and measuring that length afterward. If you use this method, choose material that does not stretch and keep it under your control throughout.
Let your dog stand comfortably on a level surface with good footing. A second adult can help keep the session calm while you read the tape. Pause if your dog moves away or becomes uncomfortable; forcing a position makes the measurement harder to trust.
3. Measure the chest all the way around
When the chart asks for chest girth at the widest point, pass the tape around the rib cage behind the front legs, as shown in Ruffwear's girth diagram. This is a circumference, not the distance across the back or between the front legs.
Keep the tape flat and check its position on both sides. Use the tension specified by the manufacturer; do not pull it tight into the body or add an arbitrary allowance. Record the reading and the units, then repeat it. If the readings differ, reset the tape and check your placement.
4. Take any additional measurements requested
Do not substitute a collar measurement for a harness-neck measurement without checking the diagram. Kurgo, for instance, measures around the broader area just above the shoulders, below the usual collar position. That instruction applies to its guide; other designs may show a different path.
Use this record while comparing the selected harness:
| Record | What to write down |
|---|---|
| Product | Brand, exact model, and chart link |
| Chest | Measurement, units, and repeat reading |
| Other required dimensions | Each measurement, using the chart's labels |
| Candidate size | The row containing the required measurements |
| Unresolved question | An overlapping boundary, missing dimension, or fit concern |
5. Resolve size overlaps before buying
If the chart requires both neck and chest measurements, check both in the same size row. When two sizes overlap, use that model's guidance for choosing between them. If one measurement fits and another falls outside the range, contact the maker rather than averaging them.
Send the actual readings and units with your question. “Chest 24 inches, lower neck 15 inches” is clearer than “medium-size dog.” These example numbers are not a size recommendation.
6. Check the fit on your dog
Follow the model's fastening and adjustment instructions, including its specified clearance under the straps. In an enclosed area, watch your dog walk, turn, and sit. Dogs Trust emphasizes unrestricted movement and a gradual, comfortable introduction.
Stop and reassess if the harness rotates, rubs, or allows your dog to wriggle out; Kurgo lists these as signs of poor fit. Do not rely on an unresolved fit for a walk. Recheck measurements during growth or body-size changes.
Bring your completed record to PawShips' dog collars and harnesses, then compare the individual product's chart and instructions before choosing a size.
Photo: Jackson Jost / Unsplash