FREE TOWCHECK WORKSHEET

RV Water Weight Calculator

See what fresh, gray and black tank contents add to the loaded vehicle or trailer.

Total volume0 US gal
Approximate water weight0 lb
Metric equivalent0 kg
LAST UPDATEDJuly 20, 2026
REVIEW STATUSSource-reviewed by TowCheck
SOURCES CHECKEDJuly 20, 2026

Methodology: Calculations are derived from official manufacturer towing guides, NHTSA regulations, and tire load specifications. Read calculation methodology or report a correction.

HOW TO USE THIS TOOL

Water Weight: what the result means

Use to compare travel-with-water scenarios before loading.

Steps

  1. Enter gallons carried in each tank.
  2. Review individual and total tank weights.
  3. Add the result to the trailer worksheet.

Formula

Water weight = US gallons × 8.34 lb; kilograms = pounds ÷ 2.2046226218.

Important limits

  • Tank contents are approximations and waste density varies.
  • Do not exceed tank or trailer ratings.