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Refrigerant Charge Calculator

Work out refrigerant charge instantly with clear inputs, formula shown and shareable results.

About Refrigerant Charge Calculator

A split system leaves the factory holding enough refrigerant for a stated line set length. Any liquid line beyond that allowance needs extra charge at the manufacturer's ounces-per-foot figure, which depends on line diameter. Sixteen ounces to the pound converts between the site measurement and the nameplate units.

Formulas

Additional charge

oz to add = (line length - included length) x oz per foot

Total charge

Total lb = (factory lb x 16 + oz added) / 16

Worked example

With the default values below, Refrigerant Charge Calculator returns Total system charge of 6.94. Change any input above and every figure here is recalculated in your browser.

Inputs used

Factory chargeminimum 0.1 lb
6 lb
Total liquid line lengthminimum 0 ft
40 ft
Line length included in factory chargeminimum 0 ft
15 ft
Charge per extra footminimum 0.05 oz/ft
0.6 oz/ft

Results

Total system charge
6.94 lb
Charge to add on site
15.0 oz
Charge to add in pounds
0.94 lb
Total charge in ounces
111 oz

Step by step

  1. 1Values used
  2. 2Additional charge
  3. 3Total charge
  4. 4Total system charge= 6.94 lb
  5. 5Charge to add on site= 15.0 oz
  6. 6Charge to add in pounds= 0.94 lb
  7. 7Total charge in ounces= 111 oz

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Preliminary estimate only. Refrigerant handling requires certification; always follow the equipment manufacturer's charging procedure.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Refrigerant handling requires certification; always follow the equipment manufacturer's charging procedure.

Frequently Asked Questions

How is the Refrigerant Charge figure worked out?

oz to add = (line length - included length) x oz per foot. A split system leaves the factory holding enough refrigerant for a stated line set length.

Should I trust the calculation over measurement?

Use it to know roughly what to expect, then confirm with superheat or subcooling readings. The line-length rule cannot see restrictions, leaks or a mis-set metering device.

What values do I need to enter?

This calculator takes 4 inputs: Factory charge, Total liquid line length, Line length included in factory charge, Charge per extra foot. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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