# Tankless Sizing Calculator (GPM) | Total Tankless

> Calculate the right tankless water heater GPM rating for your home. Free tool — accounts for bathrooms, simultaneous use, and climate.

URL: https://totaltankless.com/resources/tankless-sizing-calculator/

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 Calculator

# Tankless Sizing Calculator (GPM)

Find the right tankless GPM rating based on your home's simultaneous hot-water demand and climate.

Number of Bathrooms1 bathroom2 bathrooms3 bathrooms4+ bathrooms

Max simultaneous hot-water fixtures used1 (e.g., one shower at a time)2 (typical family)3 (large household)4+ (very high demand)

Climate / Inlet Water TemperatureWarm (FL, AZ, southern CA, TX) — 70°F inletModerate (NC, VA, NJ, NV, mid-CA) — 60°F inletCool (PA, MD, IN, NY upstate) — 50°F inletCold (MA, CO, UT mountain) — 40°F inlet

Desired Hot Water Temperature110°F (low — household with kids)120°F (standard)130°F (high — for laundry/dishwasher)

## Related Services

tankless water heater installation

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## Want a Specialist to Run These Numbers For You?

A vetted local tankless installer will verify sizing, gas-line capacity, and venting on a free virtual estimate.

Get Free Virtual Estimate

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Call (833) 350-5930

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