Superheat and subcooling calculator for R-410A

Updated October 31, 2026

Enter the gauge pressures and pipe temperatures you measured. The calculator converts each pressure to its R-410A saturation temperature and shows the superheat and subcooling, with the steps.

Suction side (superheat)

Suction pressure (psig)

Suction line temperature (°F)

Target superheat, optional (°F)

Liquid side (subcooling)

Liquid line pressure (psig)

Liquid line temperature (°F)

Target subcooling, optional (°F)

How the calculator works

R-410A is a blend, so it boils and condenses over a small temperature range called glide, about 0.2°F. Each pressure therefore has two saturation temperatures. The calculator uses the right one for each side:

Superheat = suction line temperature − dew point temperature at the suction pressure. Dew point is where the last liquid has boiled off.
Subcooling = bubble point temperature at the liquid pressure − liquid line temperature. Bubble point is where the first vapor would form.

The saturation temperatures come from a pressure-temperature table in 1°F steps from -40°F to 150°F, with straight-line interpolation between steps. The table values match the Chemours R-410A PT chart to 0.1 psig. You can see it on our R-410A PT chart page.

Worked example

Suction gauge reads 118.4 psig. The dew point at 118.4 psig is 40.0°F. The suction line, measured 6 inches from the outdoor service valve, reads 50°F. Superheat = 50 − 40 = 10.0°F.

Liquid gauge reads 318.5 psig. The bubble point at 318.5 psig is 100.0°F. The liquid line reads 90°F. Subcooling = 100 − 90 = 10.0°F.

What to compare the result to

TXV or EEV systems are charged by subcooling. The target is on the outdoor unit's nameplate or in its installation manual, often around 8 to 12°F.
Fixed orifice or piston systems are charged by superheat. The target changes with indoor wet-bulb and outdoor dry-bulb temperature, so read it from the manufacturer's charging chart for that unit.

Readings are only meaningful after the system has run 10 to 15 minutes with a clean filter and coils.

Limits

This is for R-410A only. R-32, R-454B and R-22 have different pressure tables. A wrong refrigerant, a poorly attached probe or a gauge that is out of calibration will give a wrong answer. Under US EPA Section 608 rules, adding or recovering refrigerant is work for a certified technician.

Frequently asked questions

What is a normal superheat for R-410A?

There is no single number. On a fixed orifice system the target depends on indoor wet-bulb and outdoor temperature and is read from the manufacturer chart. On a TXV system superheat is usually somewhere around 8 to 12 degrees F, but the charge is set by subcooling.

Why does the calculator use two different saturation temperatures?

R-410A is a near-azeotropic blend with a glide of about 0.2 degrees F. The dew point is used for superheat on the vapor side and the bubble point for subcooling on the liquid side, which is how the Chemours PT chart lists them.

Where should I take the line temperatures?

Take the suction temperature on the large insulated line about 6 inches from the service valve, and the liquid temperature on the small line near its service valve. Insulate the probe so ambient air does not affect it.