GPM to Tons Calculator
Convert water flow rate (GPM) to tons of refrigeration for HVAC chillers, cooling towers, and hydronic systems. Calculate cooling capacity with temperature difference.
Calculate tons of refrigeration from water flow rate and temperature difference. Essential for chiller sizing, cooling tower selection, and hydronic system design.
GPM to Tons Converter
Water flow rate through chiller or coil
Temperature difference between supply and return water (typical: 10-14°F)
Select fluid type for accurate specific heat
Standard uses 500 constant; Detailed calculates with specific properties
Efficiency & Safety Factors
Calculation Results
Enter flow rate and temperature difference
then click "Calculate" for results
What is GPM to Tons Conversion?
GPM to Tons conversion is a fundamental calculation in HVAC engineering used to determine the cooling capacity of water-based cooling systems. This conversion is essential for chiller sizing, cooling tower selection, and hydronic system design.
1 Ton of Refrigeration = 12,000 BTU/hr = The amount of heat needed to melt 1 ton of ice in 24 hours. In water systems, this translates to approximately 2.4 GPM per ton at a 10°F temperature difference.
The GPM to Tons Formula
The standard formula for converting GPM to tons uses the heat transfer equation:
- GPM = Water flow rate in gallons per minute
- 500 = Constant (8.33 lb/gal × 60 min/hr × 1 BTU/lb·°F)
- ΔT = Temperature difference in °F (supply - return)
- 12,000 = BTU/hr per ton of refrigeration
Detailed Engineering Formula
For more precise calculations with different fluids:
GPM = 100, ΔT = 12°F, Water (Cp = 1.0)
Tons = (100 × 500 × 12) ÷ 12,000 = 50 tons
BTU/hr = 50 × 12,000 = 600,000 BTU/hr
How to Use This Calculator
Input your water flow rate in GPM, L/min, or m³/hr
Enter the temperature difference (ΔT) between supply and return
Click Calculate to see tons, BTU/hr, and kW
GPM to Tons Reference Table
Quick reference table for common GPM to Tons conversions at various temperature differences:
| GPM | ΔT (°F) | BTU/hr | Tons | kW |
|---|---|---|---|---|
| 10 GPM | 10°F | 50,000 | 4.17 | 14.6 |
| 20 GPM | 10°F | 100,000 | 8.33 | 29.3 |
| 30 GPM | 12°F | 180,000 | 15.00 | 52.8 |
| 40 GPM | 10°F | 200,000 | 16.67 | 58.6 |
| 50 GPM | 12°F | 300,000 | 25.00 | 87.9 |
| 60 GPM | 10°F | 300,000 | 25.00 | 87.9 |
| 75 GPM | 12°F | 450,000 | 37.50 | 131.9 |
| 100 GPM | 10°F | 500,000 | 41.67 | 146.5 |
| 100 GPM | 12°F | 600,000 | 50.00 | 175.8 |
| 125 GPM | 12°F | 750,000 | 62.50 | 219.8 |
| 150 GPM | 10°F | 750,000 | 62.50 | 219.8 |
| 150 GPM | 12°F | 900,000 | 75.00 | 263.7 |
| 200 GPM | 10°F | 1,000,000 | 83.33 | 293.1 |
| 200 GPM | 12°F | 1,200,000 | 100.00 | 351.7 |
| 250 GPM | 12°F | 1,500,000 | 125.00 | 439.6 |
| 300 GPM | 10°F | 1,500,000 | 125.00 | 439.6 |
| 300 GPM | 12°F | 1,800,000 | 150.00 | 527.5 |
| 400 GPM | 12°F | 2,400,000 | 200.00 | 703.4 |
| 500 GPM | 10°F | 2,500,000 | 208.33 | 732.7 |
| 500 GPM | 12°F | 3,000,000 | 250.00 | 879.2 |
| 600 GPM | 12°F | 3,600,000 | 300.00 | 1055.0 |
A common rule of thumb is 2.4 GPM per ton at 10°F ΔT, or 2 GPM per ton at 12°F ΔT. Always verify with actual design conditions and consider safety factors for chiller sizing. Higher ΔT means lower flow requirements and smaller pipes, but may affect heat transfer efficiency.
Common ΔT Values
| Application | Typical ΔT (°F) | GPM/Ton |
|---|---|---|
| Standard Comfort Cooling | 10°F | 2.4 |
| Standard Chiller Application | 12°F | 2.0 |
| High ΔT Systems | 14-16°F | 1.5-1.7 |
| Data Center Cooling | 15-20°F | 1.2-1.6 |
| Condenser Water (Cooling Tower) | 10°F | 3.0 |