RV Tank Capacity Calculator
Free RV tank calculator - estimate how long fresh water, gray and black tanks will last. Calculate water usage per person for camping and boondocking trips.
For educational purposes only. Always verify specifications with manufacturers and consult qualified RV technicians for safety-critical decisions. See our Terms of Service.
Your Tank Sizes
gal
gal
gal
people
Usage Style
This affects estimated gallons per person per day.
Estimated Duration
Fresh Water Lasts
-- days
Gray Tank Full In
-- days
Black Tank Full In
-- days
Typical Water Usage
Per Person Per Day Estimates
- Conservative: 5-8 gal fresh, 4-6 gal gray, 2-3 gal black
- Moderate: 10-15 gal fresh, 8-12 gal gray, 3-5 gal black
- Liberal: 20-25 gal fresh, 15-20 gal gray, 5-7 gal black
Conservation Tips
- Navy showers - wet, soap, rinse (saves 10+ gal/shower)
- Use campground facilities when available
- Catch rinse water for flushing
- Use paper plates to reduce dish washing