Refrigerant Line Charge Calculator
Calculate additional refrigerant charge for HVAC line sets. Select refrigerant type (R-410A, R-22, R-407C), system tonnage, and both liquid and suction line sizes.
โ๏ธ Refrigerant Line Charge Calculator
LINE SET
CHARGE REQUIRED
TOTAL LINE CHARGE
๐ก Refrigerant Line Set Charging
When installing a split-system air conditioner or heat pump, the refrigerant line set connects the outdoor condenser to the indoor evaporator. Factory charge covers a standard line length โ any line beyond that requires additional refrigerant calculated from the liquid and suction line charge rates.
The calculator above supports 3 refrigerant types (R-410A, R-22, R-407C), 7 system tonnage presets with auto-filled factory data, and separate liquid + suction line calculations for accurate total charge.
Calculate line volume with our pipe volume calculator. Size your HVAC with our furnace BTU calculator. Calculate airflow with our CFM calculator.
R-410A Liquid Line Charge (oz per foot)
The liquid line (small line) carries high-pressure liquid refrigerant from the condenser to the expansion valve.
| Line Size | oz/ft | Common System |
|---|---|---|
| 1/4" | 0.19 | 1โ1.5 ton |
| 5/16" | 0.30 | 2 ton |
| 3/8" | 0.43 | 2.5โ5 ton (most common) |
| 1/2" | 0.78 | 5+ ton / commercial |
| 5/8" | 1.22 | Large commercial |
| 3/4" | 1.76 | Large commercial |
| 7/8" | 2.40 | Large commercial |
R-410A Suction Line Charge (oz per foot)
The suction line (large line) carries low-pressure gas from the evaporator back to the compressor. It has lower charge per foot because the refrigerant is in gas form.
| Line Size | oz/ft | Common System |
|---|---|---|
| 1/2" | 0.12 | Mini-split |
| 5/8" | 0.19 | 1โ1.5 ton |
| 3/4" | 0.28 | 2โ3 ton |
| 7/8" | 0.38 | 3โ4 ton |
| 1-1/8" | 0.62 | 4โ5 ton |
| 1-3/8" | 0.93 | 5+ ton |
System Tonnage & Factory Charge
| System | BTU | Factory Charge (approx) | Factory Line (ft) | Liquid Line | Suction Line |
|---|---|---|---|---|---|
| 1.5 Ton | 18,000 | 72 oz (4.5 lbs) | 15 ft | 1/4" | 5/8" |
| 2 Ton | 24,000 | 96 oz (6 lbs) | 15 ft | 5/16" | 3/4" |
| 2.5 Ton | 30,000 | 112 oz (7 lbs) | 15 ft | 3/8" | 3/4" |
| 3 Ton | 36,000 | 128 oz (8 lbs) | 15 ft | 3/8" | 3/4" |
| 3.5 Ton | 42,000 | 152 oz (9.5 lbs) | 25 ft | 3/8" | 7/8" |
| 4 Ton | 48,000 | 176 oz (11 lbs) | 25 ft | 3/8" | 7/8" |
| 5 Ton | 60,000 | 210 oz (13 lbs) | 25 ft | 3/8" | 1-1/8" |
Always check your unit's nameplate for exact factory charge โ these are typical values and vary by manufacturer.
Step-by-Step Estimation
Step 1: Identify Your System
Find system tonnage, refrigerant type, and factory charge on the unit's data plate (outdoor condenser). Note the factory line set length.
Step 2: Measure Total Line Length
Measure actual line set from condenser to evaporator, including vertical rises. Calculate extra length: total length minus factory line length.
Step 3: Calculate Additional Charge
Look up liquid and suction line charge rates for your refrigerant type. Multiply extra length ร (liquid rate + suction rate).
Example: 3 Ton R-410A, 50 ft total run, factory 15 ft: Extra = 35 ft ร (0.43 + 0.28) = 35 ร 0.71 = 24.9 oz (1.55 lbs) additional charge.
R-22 vs R-410A Charge Rates
| Line Size | R-410A (oz/ft) | R-22 (oz/ft) | Difference |
|---|---|---|---|
| 3/8" liquid | 0.43 | 0.34 | R-410A is 26% more |
| 3/4" suction | 0.28 | 0.14 | R-410A is 2ร more |
| 7/8" suction | 0.38 | 0.19 | R-410A is 2ร more |
R-410A requires significantly more charge per foot than R-22, especially on suction lines. Systems converting from R-22 to R-407C require different charge calculations โ do not use R-22 rates for R-407C.