Viscosity of Air: Dynamic & Kinematic Calculator

Air Dynamic (Absolute) Viscosity Chart

Dynamic viscosity of dry air vs temperature in degrees Fahrenheit at 1 atm, 10 bar and 100 bar, with the Sutherland law curve at 1 atm

Dry air, calculated with CoolProp 7.2.0 (Lemmon & Jacobsen 2004). The dotted line is Sutherland's law at 1 atm. Uncertainty about 5 %. Above about 600 °C it is less certain.

Air Kinematic Viscosity Chart

Kinematic viscosity of dry air vs temperature in degrees Fahrenheit at 1 atm, 10 bar and 100 bar

Kinematic viscosity ν = μ/ρ, from the same CoolProp calculation. Y-axis is logarithmic. Kinematic viscosity falls strongly with pressure because the density rises.

Air Viscosity Calculator

Degrees (°F):

Degrees (°C):

Pressure:

Dynamic (absolute) viscosity

Pa·s:

µPa·s:

Centipoise (cP = mPa·s):

lbm/(ft·s):

lbf·s/ft²:

Kinematic viscosity

m²/s:

mm²/s (= cSt):

Stokes (cm²/s):

ft²/s:

Sutherland's law (1 atm only)

µPa·s:

Sutherland minus CoolProp (%):

Dry air, absolute pressure. Range: −100 to 1000 °C (−148 to 1832 °F) and 1 atm to 100 bar (14.696 to 1450 psia). Outside it the calculator shows “Out of Range”. Values are interpolated linearly in temperature (10 °C grid) and in ln P between 1 atm, 2, 5, 10, 20, 50 and 100 bar. Interpolation adds about 0.1 % at most (checked against CoolProp at six off-grid points).

Viscosity of Air

Quick answer

Dry air at 20 °C and 1 atm has a dynamic viscosity of 18.21 µPa·s (0.01821 cP) and a kinematic viscosity of 15.11 mm²/s. This page is for dry air.

Unlike a liquid, a gas gets more viscous as it gets hotter. Air viscosity rises with temperature by a factor of about 4 between −100 and 1000 °C. It barely changes with pressure below about 10 bar.

Dynamic and kinematic viscosity

Dynamic (absolute) viscosity μ is the resistance to shear. Kinematic viscosity is μ divided by density:

ν = μ / ρ

Because air density changes with pressure and temperature, kinematic viscosity changes much more than dynamic viscosity. At 100 bar the kinematic viscosity is about 100 times lower than at 1 atm. Use μ for pressure drop and the Reynolds number in pipe velocity work. Use ν for flow around bodies and boundary layers. Density comes from the air density page.

Sutherland's law

Sutherland's law is a two-constant formula for gas viscosity:

μ = μ₀ (T/T₀)^3/2 (T₀ + S) / (T + S)

with μ₀ = 1.716×10⁻⁵ Pa·s at T₀ = 273.15 K and S = 110.4 K. S = 110.4 K and β = 1.458×10⁻⁶ kg/(s·m·K^1/2) are the U.S. Standard Atmosphere 1976 constants (eq. 51). μ₀ follows from them. Against CoolProp, Sutherland is -0.56 % at −100 °C, -0.40 % at 20 °C and -5.5 % at 1000 °C. It is good near ambient and drifts at high temperature. The Standard Atmosphere itself says the law fails at very high and very low temperatures.

Where the numbers come from

Accuracy. Lemmon et al. (2000) state an uncertainty of about 0.1 % in density, 0.2 % in speed of sound and 1 % in heat capacity from the solidification point to 873 K (600 °C) and up to 70 MPa. Above 873 K there were no reliable air data, so nitrogen data were used and the paper gives about 0.5 % for density. Lemmon & Jacobsen (2004) state about 5 % for the viscosity and thermal conductivity of air, and more near the critical point. Viscosity and conductivity above about 600 °C, and the 1000 °C end of the range, are less certain than that. CoolProp uses a molar mass of 28.96546 g/mol, the U.S. Standard Atmosphere uses 28.9644 g/mol. That is the main reason CoolProp density at 15 °C and 1 atm is 0.04 % above the Standard Atmosphere value.

Dry Air Viscosity at 1 atm (101.325 kPa)

Dynamic and kinematic viscosity of dry air every 20 °C from −100 to 1000 °C at 1 atm.

Temp (°C)	Temp (°F)	μ (µPa·s)	μ (lbm/(ft·s) ×10⁻⁵)	ν (mm²/s)	ν (ft²/s ×10⁻⁴)	Sutherland μ (µPa·s)	Sutherland minus CoolProp (%)
-100.0	-148.0	11.78	0.7916	5.756	0.6196	11.71	-0.557
-80.00	-112.0	12.94	0.8698	7.064	0.7604	12.89	-0.399
-60.00	-76.00	14.07	0.9453	8.478	0.9126	14.02	-0.318
-40.00	-40.00	15.15	1.018	9.995	1.076	15.11	-0.290
-20.00	-4.000	16.20	1.089	11.61	1.250	16.15	-0.301
0	32.00	17.22	1.157	13.32	1.433	17.16	-0.339
20.00	68.00	18.21	1.223	15.11	1.627	18.13	-0.398
40.00	104.0	19.17	1.288	17.00	1.830	19.07	-0.472
60.00	140.0	20.10	1.351	18.97	2.042	19.99	-0.556
80.00	176.0	21.01	1.412	21.02	2.262	20.87	-0.648
100.0	212.0	21.90	1.471	23.15	2.492	21.73	-0.746
120.0	248.0	22.76	1.530	25.36	2.729	22.57	-0.848
140.0	284.0	23.61	1.587	27.64	2.975	23.39	-0.953
160.0	320.0	24.44	1.642	30.00	3.229	24.18	-1.06
180.0	356.0	25.25	1.697	32.42	3.490	24.96	-1.17
200.0	392.0	26.05	1.750	34.92	3.759	25.71	-1.28
220.0	428.0	26.83	1.803	37.49	4.035	26.45	-1.39
240.0	464.0	27.59	1.854	40.12	4.319	27.18	-1.50
260.0	500.0	28.34	1.905	42.83	4.610	27.89	-1.61
280.0	536.0	29.08	1.954	45.59	4.907	28.58	-1.72
300.0	572.0	29.81	2.003	48.42	5.212	29.27	-1.83
320.0	608.0	30.53	2.051	51.31	5.523	29.94	-1.93
340.0	644.0	31.23	2.099	54.27	5.841	30.59	-2.04
360.0	680.0	31.92	2.145	57.28	6.166	31.24	-2.15
380.0	716.0	32.61	2.191	60.36	6.497	31.87	-2.26
400.0	752.0	33.28	2.237	63.50	6.835	32.50	-2.37
420.0	788.0	33.95	2.281	66.69	7.178	33.11	-2.47
440.0	824.0	34.61	2.325	69.94	7.529	33.71	-2.58
460.0	860.0	35.26	2.369	73.25	7.885	34.31	-2.68
480.0	896.0	35.90	2.412	76.62	8.247	34.90	-2.79
500.0	932.0	36.53	2.455	80.04	8.616	35.47	-2.89
520.0	968.0	37.16	2.497	83.52	8.990	36.04	-3.00
540.0	1004	37.78	2.538	87.05	9.370	36.60	-3.10
560.0	1040	38.39	2.580	90.64	9.757	37.16	-3.21
580.0	1076	39.00	2.620	94.28	10.15	37.71	-3.31
600.0	1112	39.60	2.661	97.98	10.55	38.24	-3.41
620.0	1148	40.19	2.701	101.7	10.95	38.78	-3.52
640.0	1184	40.78	2.740	105.5	11.36	39.30	-3.62
660.0	1220	41.36	2.780	109.4	11.77	39.82	-3.72
680.0	1256	41.94	2.818	113.3	12.19	40.34	-3.83
700.0	1292	42.52	2.857	117.3	12.62	40.85	-3.93
720.0	1328	43.09	2.895	121.3	13.05	41.35	-4.03
740.0	1364	43.65	2.933	125.3	13.49	41.85	-4.13
760.0	1400	44.21	2.971	129.4	13.93	42.34	-4.24
780.0	1436	44.77	3.008	133.6	14.38	42.82	-4.34
800.0	1472	45.32	3.045	137.8	14.83	43.31	-4.44
820.0	1508	45.86	3.082	142.1	15.29	43.78	-4.54
840.0	1544	46.41	3.119	146.4	15.76	44.25	-4.64
860.0	1580	46.95	3.155	150.8	16.23	44.72	-4.75
880.0	1616	47.48	3.191	155.2	16.70	45.18	-4.85
900.0	1652	48.02	3.227	159.6	17.18	45.64	-4.95
920.0	1688	48.55	3.262	164.1	17.67	46.09	-5.05
940.0	1724	49.07	3.298	168.7	18.16	46.54	-5.15
960.0	1760	49.60	3.333	173.3	18.66	46.99	-5.26
980.0	1796	50.12	3.368	178.0	19.16	47.43	-5.36
1000	1832	50.63	3.403	182.7	19.66	47.87	-5.46

Calculated with CoolProp 7.2.0. Sutherland: μ₀ = 1.716×10⁻⁵ Pa·s, T₀ = 273.15 K, S = 110.4 K.

Dry Air Viscosity at 1 atm, 10 bar and 100 bar

At selected temperatures and three pressures.

Temp (°C)	Temp (°F)	Pressure (bara)	Pressure (psia)	μ (µPa·s)	μ (lbm/(ft·s) ×10⁻⁵)	ν (mm²/s)	ν (ft²/s ×10⁻⁴)
1 bara (1 atm, 14.7 psia)
-100	-148.0	1.013	14.7	11.78	0.7916	5.756	0.6196
0	32.00	1.013	14.7	17.22	1.157	13.32	1.433
100	212.0	1.013	14.7	21.90	1.471	23.15	2.492
200	392.0	1.013	14.7	26.05	1.750	34.92	3.759
400	752.0	1.013	14.7	33.28	2.237	63.50	6.835
600	1112	1.013	14.7	39.60	2.661	97.98	10.55
800	1472	1.013	14.7	45.32	3.045	137.8	14.83
1000	1832	1.013	14.7	50.63	3.403	182.7	19.66
10 bara (145 psia)
-100	-148.0	10	145	11.98	0.8049	0.5721	0.06158
0	32.00	10	145	17.36	1.167	1.354	0.1457
100	212.0	10	145	22.01	1.479	2.360	0.2541
200	392.0	10	145	26.14	1.756	3.561	0.3833
400	752.0	10	145	33.35	2.241	6.468	0.6962
600	1112	10	145	39.65	2.664	9.971	1.073
800	1472	10	145	45.36	3.048	14.01	1.509
1000	1832	10	145	50.67	3.405	18.57	1.999
100 bara (1450 psia)
-100	-148.0	100	1450	20.39	1.370	0.06673	0.007183
0	32.00	100	1450	19.65	1.321	0.1495	0.01609
100	212.0	100	1450	23.46	1.576	0.2573	0.02769
200	392.0	100	1450	27.22	1.829	0.3836	0.04128
400	752.0	100	1450	34.08	2.290	0.6844	0.07367
600	1112	100	1450	40.21	2.702	1.043	0.1122
800	1472	100	1450	45.81	3.078	1.454	0.1565
1000	1832	100	1450	51.05	3.430	1.915	0.2061

The calculator above covers 2, 5, 20 and 50 bar as well.

Related Air Pages and Tools

Compare with water viscosity. Use viscosity with density for the Reynolds number in pipe velocity and orifice flow calculations.

Sources

E. W. Lemmon, R. T. Jacobsen, S. G. Penoncello and D. G. Friend, “Thermodynamic Properties of Air and Mixtures of Nitrogen, Argon, and Oxygen From 60 to 2000 K at Pressures to 2000 MPa,” J. Phys. Chem. Ref. Data 29(3), 331–385, 2000. doi:10.1063/1.1285884. Equation of state for dry air: density, specific heats, speed of sound, compressibility factor. Opened the NIST reprint, accessed 25 Oct 2026.
E. W. Lemmon and R. T. Jacobsen, “Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air,” Int. J. Thermophys. 25(1), 21–69, 2004. doi:10.1023/B:IJOT.0000022327.04529.f3. Viscosity and thermal conductivity of air. Only the abstract was read (NIST publication page), accessed 25 Oct 2026.
I. H. Bell, J. Wronski, S. Quoilin and V. Lemort, “Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp,” Ind. Eng. Chem. Res. 53(6), 2498–2508, 2014. doi:10.1021/ie4033999. The software used (CoolProp 7.2.0, fluid “Air”) to evaluate the two correlations above.
NOAA, NASA and USAF, U.S. Standard Atmosphere, 1976, NASA-TM-X-74335. ntrs.nasa.gov/citations/19770009539. Sea-level reference values, dry-air composition and Sutherland constants, accessed 25 Oct 2026.

All numbers on this page are calculated, not measured here. See the Air General Properties page for the accuracy statements and the cross-check against the U.S. Standard Atmosphere.

Dynamic and Kinematic Viscosity of Dry Air Calculator and Charts

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