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What Size Wood Chipper Do I Need? Sizing by Branch Diameter and Power
The size of a wood chipper is set by one number: the largest branch diameter it is rated to chip. Pick that first, then pick the power source that can drive it: an engine (gas on most models), your tractor's PTO, or a skid steer's hydraulics. Engine size, feed system and price follow from those two choices. Below, the capacity classes and the power each one needs on the chippers we carry, how PTO and skid-steer chippers are matched to a machine, and the safety rules that apply to every chipper.
Wood Chipper Sizes at a Glance
Measure the thickest branches you will chip regularly, not the one oversized limb you might cut once a year, and choose a chipper rated at or above that diameter. The ranges below come from the published specifications of the chippers in our current range; always confirm the exact model's rating before you buy.
| Rated max branch diameter | Engine-driven (as listed) | Tractor PTO or skid steer (as listed) | Typical use |
|---|---|---|---|
| 3 in | 212 cc, about 7 hp | — | Garden pruning and small yard cleanup |
| 4 in | 196–420 cc, about 6.5–13 hp | 3-point PTO for 18–45 HP tractors; skid steer at 14–20 gal/min | Larger residential lots, storm cleanup |
| 5 in | 420–459 cc, about 14–15 hp | — | Acreage and regular brush clearing |
| 6 in | 389–459 cc, about 11.7–15 hp; one road-towable hydraulic-feed model at 627 cc, 23 hp | 3-point PTO, hydraulic feed, for 20–50 HP tractors; one gravity-feed PTO model for larger tractors (confirm its rated range with us) | Farms, woodlots, land clearing |
| 7 in | 688–750 cc twin cylinder, 22–25 hp, hydraulic feed | — | Heavy brush, contractor and property-management work |
| 8 in | 688–1000 cc, 22–35 hp | — | Commercial-duty chipping |
| 9 in | 24.8 hp Kubota diesel, road-towable, hydraulic feed | — | Tree-care and municipal work |
Two things change between classes besides branch size: how fast the chipper can take material, and how hard it is to feed. Most smaller chippers rely on gravity and you to push branches in. Many larger models, including the 7-inch twin-cylinder and several 6- to 9-inch towable and PTO units, use hydraulic feed rollers that pull material in at a steady rate, which reduces operator effort and keeps hands farther from the infeed.
Gas Engine, Tractor PTO or Skid Steer?
Gas-engine chippers are self-contained. You can tow or wheel them anywhere, and the engine is sized to the chipper, so there is nothing to match. They suit homeowners and anyone without a tractor.
PTO chippers run off a tractor's power take-off. Three numbers must match your tractor:
- Horsepower. Your tractor must fall inside the chipper's rated range. Listings state either tractor horsepower or required PTO horsepower; PTO horsepower is lower than the engine rating printed on most tractors, so check your tractor's manual for both.
- PTO speed. The PTO chippers we carry are rated for a 540 RPM PTO.
- Hitch category. The 3-point PTO chippers we carry mount to a Category 1 hitch. Most compact and utility tractors use Category 1, but check yours, especially on larger tractors.
Skid-steer chippers are driven by the loader's auxiliary hydraulics. Match the chipper's rated flow range (for example 14–20 gallons per minute) to your machine's auxiliary flow before buying.
Drum vs Disc Chippers
Both designs use spinning knives. A disc chipper mounts its knives on a flywheel disc; a drum chipper mounts them on a rotating drum. Within the same capacity class, choose by the model's rated branch diameter, power and feed system rather than by drum or disc alone.
Safety Rules That Apply to Every Chipper
Wood chippers cause serious injuries. A CDC review of U.S. occupational data counted 31 deaths involving mobile wood chippers from 1992 to 2002, most of them from being caught or compressed by the machine (CDC MMWR, December 10, 2004). The same rules apply on a homeowner's property, drawn from that report and from Ohio State University Extension's chipper and shredder safety factsheet:
- Read the operator's manual and inspect the chipper before every use, including the safety and emergency shut-off controls.
- Do not work alone.
- Keep the hood over the knives fully closed while running, and wait for all moving parts to stop completely before opening it.
- Remove stones, metal and other debris from the material first.
- Put small material such as twigs and leaves straight into your collection container or trailer instead of into the chipper.
- Wear a hard hat, eye and hearing protection, slip-resistant boots and close-fitting clothing with cuffless gloves.
- Keep children and bystanders away. The CDC report recommends that people under 18 not operate chippers.
Sources
- CDC MMWR: Fatal and Nonfatal Occupational Injuries Involving Wood Chippers, United States, 1992–2002
- Ohio State University Extension (Ohioline): Wood Chippers and Shredders Safety for Trainers and Landscapers, AEX-892.2.85
- Capacity and power ranges: manufacturer specifications on the product pages in our wood chipper collection, checked October 26, 2026.
Shop Wood Chippers
Browse every model in our wood chippers and stump grinders collection, or the full MechMaxx range. For tractor owners: the 4-inch 3-point PTO wood chipper and the 6-inch hydraulic-feed PTO wood chipper. For skid steers: the 4-inch skid steer chipper attachment. Questions about which model fits your property or tractor? Email support@urbansupplyinc.com and we will help you match it.