Estimate boat lift capacity from dry weight, fuel tank size, fuel type, gear, ballast, and safety margin to find loaded weight and recommended lift capacity.

Note: Boat lift sizing is typically based on the boat’s actual loaded (“wet”) weight plus a safety margin (commonly around 10–25%+, depending on conditions and guidance from the lift manufacturer). “Dry weight” may exclude engines, batteries, fluids, options, and gear.

Boat Lift Capacity Calculator

Basic
Custom

Quick estimate (assumes gasoline ~6.0 lb/US gal and an extra 500 lb allowance). Enter any 2 values to calculate the missing variable.

Boat Lift Capacity Formula (Loaded Weight + Safety Margin)

The following example outlines a common approach for sizing a boat lift: estimate the boat’s loaded (wet) weight, then apply a safety margin. The Custom tab matches this approach.

BLC₍rec) = W₍loaded)(1 + (M) / (100))\ W₍loaded) = DW + TS × ₍fuel) + GW + WV × 8.34

Variables:

  • BLCrec is the recommended boat lift capacity (lb)
  • Wloaded is the total loaded (wet) weight (lb)
  • DW is the boat dry weight (lb)
  • TS is the fuel volume (US gallons)
  • ρfuel is fuel density (lb/US gal), e.g., gasoline ≈ 6.0–6.3 lb/gal and diesel ≈ 7.0–7.3 lb/gal
  • GW is additional gear/passengers/accessories weight (lb)
  • WV is water/ballast volume (US gallons); fresh water is ≈ 8.34 lb/gal
  • M is the safety margin (%)

How to Calculate Boat Lift Capacity?

The following steps outline how to calculate a recommended boat lift capacity.

  1. Determine the boat’s dry weight (from manufacturer specs or a scale ticket, if available).
  2. Estimate fuel weight using tank volume and fuel density (gasoline and diesel vary by blend and temperature).
  3. Add additional weight for typical gear/passengers/accessories and any water/ballast carried.
  4. Compute the total loaded (wet) weight.
  5. Apply a safety margin (often about 10–25%+) and round up to a lift rating that meets or exceeds the result.

Example Problem :

Use the following variables as an example problem to test your knowledge.

dry weight of the boat (lbs) = 2000

gas tank size (gallons) = 100

Assume gasoline density = 6.0 lb/gal, additional gear/passengers = 500 lb, safety margin = 15%.

Fuel weight = 100 × 6.0 = 600 lb

Total loaded weight = 2000 + 600 + 500 = 3100 lb

Recommended lift capacity = 3100 × (1 + 0.15) = 3565 lb (round up to an appropriate lift rating, such as 4000 lb)