Refrigerant Pressure-Temperature Chart

Every field technician keeps a P-T chart in the truck: knowing saturation pressure tells you the evaporating temperature on gauges, and vice versa. The table below is computed from real thermodynamic property data (CoolProp) for the six most common service refrigerants.

Use it for charging checks, TXV adjustment, and diagnosis. Need full cycle state points? The superheat & subcooling calculator above builds on the same data.

Temp °C	R134a	R410A	R32	R404A	R290 (propane)	R744 (CO2)
-40°C	51.2 kPa	174.8 kPa	177.4 kPa	131 kPa	111.1 kPa	1004.5 kPa
-35°C	66.1 kPa	218.1 kPa	221.4 kPa	163.6 kPa	137.2 kPa	1202.4 kPa
-30°C	84.4 kPa	269.3 kPa	273.4 kPa	202.2 kPa	167.8 kPa	1427.8 kPa
-25°C	106.4 kPa	329.4 kPa	334.6 kPa	247.5 kPa	203.4 kPa	1682.7 kPa
-20°C	132.7 kPa	399.3 kPa	405.8 kPa	300.2 kPa	244.5 kPa	1969.6 kPa
-15°C	163.9 kPa	480 kPa	488.1 kPa	361 kPa	291.6 kPa	2290.8 kPa
-10°C	200.6 kPa	572.7 kPa	582.6 kPa	430.7 kPa	345.3 kPa	2648.7 kPa
-5°C	243.3 kPa	678.3 kPa	690.6 kPa	510.2 kPa	406 kPa	3045.9 kPa
0°C	292.8 kPa	798.1 kPa	813.1 kPa	600.3 kPa	474.5 kPa	3485.1 kPa
5°C	349.7 kPa	933.2 kPa	951.4 kPa	701.8 kPa	551.1 kPa	3969.5 kPa
10°C	414.6 kPa	1084.8 kPa	1106.9 kPa	815.7 kPa	636.6 kPa	4502.2 kPa
15°C	488.4 kPa	1254.3 kPa	1280.8 kPa	942.9 kPa	731.5 kPa	5087.1 kPa
20°C	571.7 kPa	1442.9 kPa	1474.6 kPa	1084.4 kPa	836.5 kPa	5729.1 kPa
25°C	665.4 kPa	1652.1 kPa	1689.6 kPa	1241.2 kPa	952.1 kPa	6434.2 kPa
30°C	770.2 kPa	1883.4 kPa	1927.5 kPa	1414.5 kPa	1079 kPa	7213.7 kPa
35°C	887 kPa	2138.3 kPa	2189.8 kPa	1605.3 kPa	1217.9 kPa	—
40°C	1016.6 kPa	2418.6 kPa	2478.3 kPa	1814.9 kPa	1369.4 kPa	—
45°C	1159.9 kPa	2726.1 kPa	2794.8 kPa	2044.7 kPa	1534.3 kPa	—
50°C	1317.9 kPa	3063 kPa	3141.2 kPa	2296.1 kPa	1713.3 kPa	—
55°C	1491.5 kPa	3431.6 kPa	3519.9 kPa	2570.9 kPa	1907.2 kPa	—
60°C	1681.8 kPa	3834.8 kPa	3933.2 kPa	2871.2 kPa	2116.8 kPa	—
65°C	1889.8 kPa	4276.3 kPa	4384.3 kPa	3200 kPa	2343 kPa	—
70°C	2116.8 kPa	4761.7 kPa	4876.8 kPa	3563.3 kPa	2586.8 kPa	—

Saturated vapor line, absolute pressure (kPa). Generated from real CoolProp property data. R744 (CO2) has no saturation values above its critical temperature (31.1°C) — it operates transcritically there.

Frequently asked questions

How do I read a P-T chart?

Find your refrigerant column and read across: the pressure (kPa) at which it boils/condenses at each temperature. At sea level, R410A saturated at 45°C reads ~2,730 kPa; R134a at the same temperature ~1,160 kPa.

Why is R744 (CO2) pressure so much higher?

CO2's critical temperature is 31°C — in warm ambient it operates transcritically above 7,400 kPa. That's why CO2 systems use different fittings and safety standards.

Are these values gauge or absolute pressure?

Absolute pressure in kPa. Subtract ~101.3 kPa (14.7 psi) for gauge readings at sea level.

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