Refrigerant Charge Calculator

Calculate the required refrigerant charge for HVAC/refrigeration systems based on system capacity, line set length, and refrigerant type.

Check equipment nameplate or spec sheet
Length factory charge is rated for (typically 15–25 ft)

Formulas Used

Tube Internal Volume:

ID = OD − 2 × wall_thickness

V = π × (ID/2)² × L

where L = line length, ID = internal diameter (ACR Type L copper)

Method 1 — Volume-Based Charge:

m_liquid = V_liquid × ρ_liquid

m_vapor = V_suction × ρ_vapor

Total Charge = (m_liquid + m_vapor) × 16 [oz]

where ρ_liquid = liquid refrigerant density at ~100°F (lb/ft³), ρ_vapor = vapor density at ~45°F saturated suction (lb/ft³)

Method 2 — Manufacturer Adder Method (ACCA/ASHRAE Standard):

Total Charge = Q_factory + (L_liquid − L_base) × k_liquid + L_suction × k_suction

where Q_factory = nameplate factory charge (oz), L_base = factory-rated line set length (ft), k_liquid = liquid line oz/ft adder, k_suction = suction line oz/ft adder

Assumptions & References

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