Power tools
Units: lb and kgTractor ballast calculator
A tractor with too little weight slips and wastes fuel. A tractor with too much weight compacts soil and uses fuel to carry the extra weight. This calculator gives the target total weight for the job and the ballast to add, based on the tractor's power and operating weight.
Method
How ballast targets are calculated
Ballast targets are stated as total tractor weight per PTO horsepower. If engine horsepower is entered, it is converted to PTO hp at 86 percent (see the PTO horsepower calculator).
Target weight = PTO hp × target lb per PTO hp for the drive type and job (table below). Ballast to add = target weight − operating weight. The axle split applies the front axle share from the table to the midpoint of the target weight, or to the operating weight if it is already higher.
| Job (lb per PTO hp) | 2WD | MFWD (front-wheel assist) | Articulated 4WD | Tracks |
|---|---|---|---|---|
| Heavy draft, under 5 mph (plowing, deep tillage) | 130 to 150 | 120 to 135 | 110 to 125 | 115 to 130 |
| Draft at 5 to 8 mph (discing, field cultivating, planting) | 110 to 120 | 100 to 115 | 90 to 105 | 95 to 110 |
| PTO or light draft work (mowing, baling, hauling) | 85 to 100 | 80 to 95 | 80 to 95 | 85 to 100 |
| Front axle share | 25% | 35% | 55% | 50% |
These are planning values from OEM ballasting guides and extension recommendations. Confirm the setting by measuring wheel slip in the field. The target is about 8 to 15 percent in tilled soil. Operating weight is listed on most tractor spec pages in the database.
Look up your tractor's horsepower and operating weight by power class:
FAQ
Frequently asked questions
How much should a tractor weigh per horsepower?
For heavy draft work at low speed, plan on roughly 120 to 150 lb of total tractor weight per PTO horsepower depending on drive type. Faster field work at 5 to 8 mph needs less, around 90 to 120 lb per PTO hp, and PTO or light draft work needs less again.
How do I know if my tractor is correctly ballasted?
Measure wheel slip in the field. Count drive wheel revolutions over a marked distance with and without the implement working. Slip of about 8 to 15 percent in tilled soil (lower on firm ground) means ballast is about right. Under 5 percent usually means too much weight, and over 15 percent means too little.
Where should ballast go on a front-wheel-assist tractor?
For pulling, MFWD tractors work best with about 35 to 40 percent of their weight on the front axle and the rest on the rear. Two-wheel-drive tractors carry about 25 percent on the front, and articulated 4WD tractors about 55 percent on the front. Use front weights, wheel weights, and liquid tire fill to reach the split.
Does loader work follow the same rule?
No. Loader work needs counterweight for stability rather than traction, so it is set by the loader's rated lift and the manufacturer's minimum rear ballast, usually a ballast box or filled rear tires. Check the loader manual, then use this calculator for draft and PTO jobs.
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Rated horsepower, operating weight, and tire sizes for each model are listed in the tractor spec database. Models can also be browsed by manufacturer.