Acids & bases

Phosphoric acid · H3PO4

Density, dynamic viscosity and specific heat capacity of aqueous phosphoric acid as a function of concentration and temperature, computed from the Laliberté (2009) aqueous-electrolyte correlation. Tabulated over 5–60 wt% and 0–60 °C.

Also known as: Orthophosphoric acid, White phosphoric acid
CAS number: 7664-38-2
Tabulated range: 5–60 wt% · 0–60 °C
Properties: Density · Dynamic viscosity · Specific heat capacity · Specific gravity · Degrees Baumé

At 50 wt% · 20 °C

reference snapshot

Density: 1336.0kg/m³
Density: 1.3360g/cm³
Specific gravity: 1.338
Viscosity: 5.950cP
Specific heat: 2674J/kg·K
°Baumé: 36.7heavy

Explore

Read a value at any point

Move the sliders to interpolate between the tabulated grid points. The readout and chart never go outside the validated 5–60 wt% and 0–60 °C range, and every number is interpolated from the committed table below — nothing is computed from a chemistry model in your browser.

Interactive explorer

Values are interpolated between the tabulated grid points below — sliders stay within the validated 5–60 wt% and 0–60 °C range.

Concentration33 wt%

Temperature20 °C

Density: 1203.0 kg/m³
Density: 1.2030 g/cm³
Specific gravity: 1.205
Dynamic viscosity: 2.999 cP
Specific heat: 3162 J/kg·K
°Baumé (heavy): 24.7

Density (kg/m³) vs wt% H3PO4 at 20 °C — Phosphoric acid.

Why it matters

What the numbers tell you

At 50 wt% and 20 °C, aqueous phosphoric acid has a density of about 1336 kg/m³ (1.336 g/cm³) — roughly 1.34× the density of water. Its dynamic viscosity is about 5.950 cP, against roughly 1 cP for water at the same temperature, and its specific heat is about 2.67 kJ/kg·K — about 64% of water's 4.18 kJ/kg·K. Those differences carry straight into volume-to-mass conversions, pump and pipe sizing, and the heat needed to change its temperature.

Common grades

A few working strengths

Properties at 20 °C for a handful of concentrations in everyday use, read from the committed grid (interpolated between tabulated points where a grade falls between them). The full table follows below.

wt% H3PO4	°C	Density kg/m³	SG	Viscosity cP	Sp. heat J/kg·K	°Baumé
10	20	1053.7	1.056	1.376	3880	7.6
30	20	1181.5	1.184	2.677	3252	22.5
50	20	1336.0	1.338	5.950	2674	36.7
60	20	1425.2	1.428	9.699	2410	43.4

Sources

Where the numbers come from

Every value on this page is computed by a deterministic model — none is entered by hand. The generating method and the references it is checked against:

▸Laliberte, M. (2009). A Model for Calculating the Heat Capacity of Aqueous Solutions, with Updated Density and Viscosity Data. J. Chem. Eng. Data 54(6), 1725-1760. doi:10.1021/je8008123
▸Perry's Chemical Engineers' Handbook, 7th ed. (Perry & Green) - aqueous H3PO4 density table

Model: thermo==0.4.0 (chemicals==1.3.0) - Laliberte 2009 electrolyte correlation · Generated 2026-06-07

Validation

Checked against a cited value

The model is cross-checked at one independently cited reference point. The page is published only because this check passes.

Property / point	Density · 50 wt% · 20 °C
Cited reference value	1335 kg/m3
Model computed	1336 kg/m3
Error vs reference	0.075% (tolerance 1%)

Perry's Chemical Engineers' Handbook, 7th ed.. Perry, R.H. & Green, D.W. (eds.), Perry's Chemical Engineers' Handbook, 7th ed., aqueous phosphoric acid density-concentration table: 50 wt% H3PO4 at 20 degC = 1.335 g/cm3. An anomalous third-party table value of 1.379 g/cm3 was rejected as inconsistent with Perry's and with the smooth density-vs-concentration trend (40 wt% ~ 1.255, 60 wt% ~ 1.425 g/cm3).

Full tables

Every tabulated point

Rows are temperature (°C); columns are concentration (wt% H3PO4). Read the cell at the intersection. Specific gravity is density divided by the model water reference of 998.2 kg/m³ at 20 °C.

Density — kg/m³

°C \ wt%	5	10	15	20	25	30	35	40	45	50	55	60
0	1027.4	1056.2	1086.5	1118.1	1151.4	1186.2	1222.8	1261.2	1301.6	1343.9	1388.4	1435.2
5	1027.4	1056.1	1086.2	1117.8	1150.9	1185.5	1221.9	1260.1	1300.3	1342.4	1386.6	1433.0
10	1027.0	1055.7	1085.6	1117.0	1150.0	1184.5	1220.7	1258.7	1298.6	1340.5	1384.5	1430.6
15	1026.3	1054.8	1084.7	1116.0	1148.7	1183.1	1219.2	1257.0	1296.7	1338.4	1382.1	1428.0
20	1025.3	1053.7	1083.5	1114.6	1147.2	1181.5	1217.4	1255.0	1294.5	1336.0	1379.5	1425.2
25	1024.1	1052.4	1082.0	1113.0	1145.5	1179.6	1215.3	1252.8	1292.1	1333.4	1376.8	1422.3
30	1022.6	1050.7	1080.2	1111.1	1143.5	1177.5	1213.1	1250.4	1289.6	1330.7	1373.9	1419.2
35	1020.9	1048.9	1078.3	1109.1	1141.3	1175.2	1210.6	1247.8	1286.8	1327.8	1370.8	1415.9
40	1018.9	1046.9	1076.2	1106.9	1139.0	1172.7	1208.0	1245.1	1284.0	1324.8	1367.6	1412.6
45	1016.8	1044.7	1073.9	1104.4	1136.5	1170.0	1205.2	1242.2	1280.9	1321.6	1364.3	1409.2
50	1014.6	1042.3	1071.4	1101.9	1133.8	1167.2	1202.3	1239.1	1277.8	1318.4	1360.9	1405.7
55	1012.1	1039.8	1068.8	1099.1	1130.9	1164.3	1199.3	1236.0	1274.5	1315.0	1357.5	1402.1
60	1009.6	1037.1	1066.0	1096.3	1128.0	1161.2	1196.1	1232.7	1271.1	1311.5	1353.9	1398.4

Dynamic viscosity — cP (mPa·s)

°C \ wt%	5	10	15	20	25	30	35	40	45	50	55	60
0	2.144	2.569	3.084	3.717	4.510	5.523	6.847	8.620	11.05	14.49	19.50	27.07
5	1.806	2.148	2.559	3.060	3.682	4.467	5.480	6.816	8.618	11.11	14.66	19.89
10	1.545	1.826	2.163	2.570	3.071	3.698	4.498	5.538	6.921	8.800	11.42	15.19
15	1.339	1.575	1.857	2.195	2.608	3.121	3.769	4.603	5.695	7.157	9.160	11.98
20	1.174	1.376	1.615	1.901	2.249	2.677	3.214	3.897	4.782	5.950	7.524	9.699
25	1.039	1.214	1.421	1.667	1.964	2.328	2.781	3.352	4.085	5.039	6.306	8.028
30	0.928	1.082	1.262	1.477	1.734	2.049	2.437	2.923	3.540	4.335	5.376	6.770
35	0.836	0.972	1.131	1.320	1.547	1.821	2.159	2.578	3.106	3.779	4.650	5.800
40	0.757	0.879	1.021	1.190	1.391	1.634	1.931	2.297	2.755	3.333	4.073	5.038
45	0.690	0.800	0.929	1.080	1.260	1.477	1.741	2.065	2.466	2.969	3.607	4.427
50	0.633	0.733	0.849	0.986	1.149	1.345	1.581	1.870	2.226	2.669	3.224	3.931
55	0.583	0.674	0.781	0.906	1.054	1.231	1.445	1.706	2.024	2.417	2.906	3.522
60	0.539	0.623	0.721	0.836	0.972	1.134	1.329	1.565	1.852	2.204	2.639	3.182

Specific heat capacity — J/kg·K

°C \ wt%	5	10	15	20	25	30	35	40	45	50	55	60
0	4067	3902	3736	3571	3409	3249	3092	2939	2790	2645	2504	2368
5	4054	3892	3727	3565	3404	3246	3091	2940	2793	2650	2511	2376
10	4047	3885	3723	3562	3403	3246	3093	2944	2799	2657	2520	2387
15	4042	3882	3721	3561	3404	3249	3097	2949	2805	2665	2530	2398
20	4039	3880	3721	3562	3406	3252	3102	2956	2813	2674	2540	2410
25	4037	3880	3721	3564	3409	3257	3108	2963	2821	2684	2550	2421
30	4036	3880	3723	3567	3413	3262	3114	2970	2830	2693	2561	2433
35	4036	3881	3725	3570	3417	3267	3120	2977	2838	2703	2572	2445
40	4037	3883	3728	3574	3422	3273	3127	2985	2847	2712	2582	2456
45	4038	3885	3731	3577	3426	3278	3133	2992	2855	2721	2592	2467
50	4040	3887	3734	3581	3431	3284	3140	3000	2863	2730	2602	2478
55	4042	3890	3737	3586	3436	3290	3147	3007	2871	2739	2611	2488
60	4044	3893	3741	3590	3442	3296	3153	3014	2879	2748	2621	2498

Limitations

Before you use these numbers

▸Laliberte (2009) aqueous-electrolyte correlation for H3PO4-water. Tabulated for 5-60 wt% over 0-60 degC, within the well-characterised liquid region of the correlation. Concentrated grades (for example 75-85 wt%) fall outside this tabulated range and are not extrapolated here. Values are for preliminary design; verify against vendor data for critical service.
▸Values are tabulated only inside the 5–60 wt% and 0–60 °C ranges shown; the correlation is not extrapolated beyond them here.
▸Figures are for a pure phosphoric acid–water system. Commercial grades contain impurities (for example chloride in some caustic grades) that shift density and viscosity; check the supplier's data sheet for a specific product.
▸Use for preliminary design; verify for critical service.

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