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Both calculators run independently — change the inputs on either side to compare results.

Water Tank Sizing Calculator

Determines the minimum recommended water tank capacity for a home or commercial building based on occupant count, daily usage, desired storage duration, peak demand, and a safety buffer. Essential for off-grid properties, rainwater harvesting systems, and emergency planning.

Number of Occupants (people)

Daily Usage per Person

Storage Days Required (days)

Peak Demand Factor

Safety Margin (%)

Fill in the required fields to see your result.

Water Usage

Water Heater Usage Calculator

Estimate your water heater's annual energy cost based on hot water demand and temperature rise. Ideal for comparing heater types or finding savings before buying a new unit.

Water Heater Type

Daily Hot Water Usage (gallons)

Cold Water Inlet Temperature (°F)

Target Hot Water Temperature (°F)

Energy Cost per Therm/kWh ($/unit)

Fill in the required fields to see your result.

Key differences

	Water Tank Sizing Calculator	Water Heater Usage Calculator
Category	Water Usage	Water Usage
Inputs required	5	5
Result	Recommended Tank Size (gallons)	Annual Water Heating Cost ($)
What it does	Determines the minimum recommended water tank capacity for a home or commercial building based on occupant count, daily usage, desired storage duration, peak demand, and a safety buffer. Essential for off-grid properties, rainwater harvesting systems, and emergency planning.	Estimate your water heater's annual energy cost based on hot water demand and temperature rise. Ideal for comparing heater types or finding savings before buying a new unit.