Measuring plow size comes down to a few key dimensions: blade width, blade height, and how those numbers match your vehicle. Whether you’re sizing a snow plow for a truck or ATV, or checking disc plow wear on farm equipment, the process is straightforward once you know what to measure and where.
Snow Plow Blade Width and Height
The two most important measurements on any snow plow are blade length (the full width from end to end, measured in feet or inches) and blade height (how tall the moldboard stands, typically ranging from 5 to 10 inches). Blade width determines how much snow you clear in a single pass, while height affects how much snow the plow can roll and push without spilling over the top.
To measure blade width, stretch a tape measure across the full cutting edge from one end to the other with the blade set straight, not angled. Snow plow blades for personal and light commercial use generally range from 48 to 72 inches. For height, measure from the bottom cutting edge straight up to the top of the moldboard. There’s also a measurement called gauge size, which is the distance from the top of the blade down to the center of the mounting holes. This matters when you’re ordering replacement cutting edges or wear shoes, since the bolt pattern needs to line up.
When the blade is angled (most plows angle 25 to 30 degrees left or right), the effective clearing path gets narrower than the full blade width. A 72-inch blade angled at 30 degrees clears roughly 62 inches per pass. Keep this in mind when deciding whether a plow is wide enough for your driveway or lot.
Matching Plow Size to Your Vehicle
Plow size isn’t just about the blade. It has to match what your vehicle can safely carry and push. For ATVs and UTVs, engine displacement is the simplest guide:
- 450 to 570cc ATVs: suited for light residential work like single driveways and walkways, typically paired with 48- to 54-inch blades
- 600 to 750cc ATVs: handle heavier snow, slopes, and mixed residential or small commercial routes with blades up to 60 inches
- 850 to 1,000cc+ UTVs: built for large commercial lots, long private roads, and full-size blades up to 72 inches
A good rule of thumb for ATVs is to choose a blade that extends at least a few inches past the outside of each tire. Measure your wheel track width (the distance between the outer edges of the left and right tires) and add 4 to 6 inches. This ensures the tires always ride on cleared ground.
Truck Plow Sizing and Weight Limits
For pickup trucks and larger vehicles, plow sizing depends on the truck’s Front Gross Axle Weight Rating, or FGAWR. This number, printed on the federal certification label inside the driver’s door jamb, represents the maximum weight the front axle can safely carry. A mounted snow plow hangs almost entirely off the front end, so its weight gets added directly to that axle load.
To figure out how much plow your truck can handle, you need three numbers: the FGAWR from the door sticker, the current front axle weight of the truck without a plow (a public truck scale or CAT scale can give you this), and the installed weight of the plow you’re considering (including the mounting hardware and hydraulics). If the plow pushes your front axle weight past the FGAWR, you risk accelerated wear on steering components, brakes, and suspension, and eventual axle failure. Federal safety guidance is clear that exceeding the GAWR with added equipment is not permissible, whether the vehicle is new or used.
Most half-ton trucks safely handle plows in the 400- to 500-pound range. Three-quarter-ton and one-ton trucks can carry 700 to 1,000 pounds or more up front, opening up wider, taller commercial blades. Always check the specific FGAWR for your truck rather than relying on general estimates.
Maximum Legal Width on Roads
Federal regulations cap vehicle width at 102 inches (8.5 feet) on the National Network of highways. Snow plows mounted on emergency response vehicles, including those loaded with salt or sand, can be treated as nondivisible loads by states, which gives them more flexibility. For private plow operators, blades wider than 102 inches may require a special use permit from your state’s department of transportation. Most residential and light commercial plows fall well under this limit, but if you’re running a 10-foot or wider commercial blade on public roads between job sites, check your state’s permit requirements.
Measuring Disc Plows for Agriculture
If you’re measuring a disc plow or disc harrow rather than a snow plow, the key dimensions are disc diameter and concavity. Disc diameter is measured straight across the face of the blade at its widest point. Common sizes are 16, 18, and 20 inches, and the diameter directly determines maximum working depth. A rough formula: maximum cutting depth equals half the disc diameter minus half the width of the spool spacer, which typically works out to 7 to 8 inches for standard setups.
Diameter also tells you how much life a disc has left. Heavy use can wear one to two inches off the diameter per year. A disc that started at 20 inches and now measures 17 inches has lost significant cutting depth and is approaching replacement time.
Concavity, the curve or “dish” of the blade, is measured by laying a straightedge across the cutting face and checking the gap between the straightedge and the deepest point at the center. More concavity means the disc turns and lifts soil more aggressively. As discs wear, they lose both diameter and concavity, reducing their effectiveness. Checking both measurements at the start of each season gives you a reliable picture of when to budget for new blades.