NMFC Bumping Rule Calculator
Under NMFC Item 170 you may declare an artificial bumping weight on the bill of lading to lock a lower freight class - see the exact poundage required for every reachable class.
When bumping actually saves money
Bumping pays when your shipment sits just above a tier floor in PCF and the next class down is close. Example: 400 pounds on a 48 x 40 x 48 inch pallet works out to 7.50 PCF, which lands in Class 125. Reaching the Class 85 floor at 12.00 PCF requires 640 pounds declared. If the Class 85 rate times your hundredweight is cheaper than Class 125 plus the risk of a reweigh, the extra declared 240 pounds pays for itself. Keep an eye on LTL freight class rules changes too: carriers periodically revise their tariffs and reweigh practices, so re-run the numbers before every tender rather than reusing an old quote.
How to bump freight class: declaring the weight on the BOL
- Compute the exact required poundage with the calculator above.
- Enter that figure as the weight on the bill of lading and note it as an artificial bumping weight.
- Confirm your carrier honors Item 170 declarations on your lane, and keep the actual weight documented in case of inspection.
Bumping is a commitment. A declared bumping weight is billable even when the carrier scale reads less. Bump only when the lower class saves more than the extra declared pounds cost, and never bump across a commodity description that no longer matches the freight.
Frequently asked questions
Can you bump freight class?
Yes. NMFC Item 170 lets a shipper declare an artificial bumping weight on the bill of lading that is higher than the actual scale reading, raising the shipment density enough to reach the floor of a lower class tier. You bill at the higher declared weight, so it only pays when the cheaper class saves more than the extra pounds cost.
Is bumping freight class legal?
It is a legitimate, widely used billing mechanism, not a loophole. The declared weight is enforceable: you authorize the carrier to bill at that figure even if the freight weighs less. Enter it transparently on the BOL and keep the true weight documented.
What is an artificial bumping weight?
It is the weight you must declare so that actual weight divided by cubic feet reaches the PCF floor of the target class. For example, 400 pounds on a 48 x 40 x 48 inch pallet is 7.50 PCF in Class 125; the Class 85 floor at 12.00 PCF requires declaring 640 pounds.
Does every carrier honor Item 170 bumping?
Most national LTL carriers honor artificial bumping weight declarations, but tariff rules vary by carrier and lane. Confirm the practice with your carrier before tendering, and record the declared figure as a bumping weight on the BOL.