GPM / Tons / ΔT Calculator

Hydronic capacity — solve for GPM, tons, or temperature difference
Solve For
GPM
—
gal/min
BTU/hr
—
BTU/hr
Formula
Tons = GPM × ΔT × 500 × Cf / 12,000

Where:
 · GPM = flow rate in gallons per minute
 · ΔT = supply/return temperature difference (°F)
 · 500 = 8.34 lb/gal × 60 min/hr × 1 BTU/lb·°F
 · Cf = fluid correction factor (1.0 for water)
 · 12,000 = BTU/hr per ton

Typical ΔT: CHW = 10–12°F  |  HHW = 20–40°F  |  Condenser = 10°F
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