Determine the right water heater size for your household. Enter the number of bedrooms, bathrooms, and occupants to calculate the recommended tank size and first hour rating. Proper sizing ensures you never run out of hot water while avoiding an oversized, inefficient unit.
Enter Your Measurements
Results
Recommended Tank Size
50
gallons
Required First Hour Rating
69
gallons
Peak Hour Demand
62
gallons
Estimated Daily Usage
80
gallons
Formula
How to Use This Calculator
How to Use
- 1
Enter the number of bedrooms and bathrooms in your home.
- 2
Enter the number of regular occupants.
- 3
Indicate whether you have a dishwasher and clothes washer.
- 4
The calculator recommends a tank size based on peak demand.
Frequently Asked Questions
Frequently Asked Questions
What size water heater for a family of 4?
Should I get a tankless water heater?
In-Depth Guides
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About This Calculator
This calculator uses the formula: Peak Demand = (Showers × 16 gal) + Dishwasher + Washer + Sinks | First Hour Rating = Peak Demand × 1.1. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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