Salts & brines

Magnesium sulfate · MgSO4

Name: Magnesium sulfate (MgSO4) aqueous solution properties
Creator: ProcessConvert
License: https://creativecommons.org/licenses/by/4.0/

Magnesium sulfate (MgSO4) is a salt; this page gives computed density, dynamic viscosity and specific heat capacity for aqueous solutions from 2–20 wt% and 15–60 °C.

Values are computed from the Laliberté (2009) aqueous-electrolyte correlation and tabulated over 2–20 wt% and 15–60 °C.

Also known as: Epsom salt (heptahydrate), Magnesium sulphate
CAS number: 7487-88-9
Tabulated range: 2–20 wt% · 15–60 °C
Properties: Density · Dynamic viscosity · Specific heat capacity · Specific gravity

At 10 wt% · 20 °C

reference snapshot

Density: 1103.3kg/m³
Density: 1.1033g/cm³
Specific gravity: 1.105
Viscosity: 1.839cP
Specific heat: 3699J/kg·K

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 2–20 wt% and 15–60 °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 2–20 wt% and 15–60 °C range.

Concentration11 wt%

Temperature20 °C

Density: 1114.3 kg/m³
Density: 1.1143 g/cm³
Specific gravity: 1.116
Dynamic viscosity: 1.980 cP
Specific heat: 3657 J/kg·K

Density (kg/m³) vs wt% MgSO4 at 20 °C — Magnesium sulfate.

Why it matters

What the numbers tell you

At 10 wt% and 20 °C, aqueous magnesium sulfate has a density of about 1103 kg/m³ (1.103 g/cm³) — roughly 1.11× the density of water. It also has a dynamic viscosity of about 1.839 cP, against roughly 1 cP for water at the same temperature, and a specific heat of about 3.70 kJ/kg·K, about 88% 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% MgSO4	°C	Density kg/m³	SG	Viscosity cP	Sp. heat J/kg·K
4	20	1039.2	1.041	1.261	3976
10	20	1103.3	1.105	1.839	3699
16	20	1171.1	1.173	2.936	3452
20	20	1219.0	1.221	4.296	3302

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
▸CRC Handbook of Chemistry and Physics, 97th ed. (Haynes, ed., 2016) - Concentrative Properties of Aqueous Solutions (density and viscosity at 20 degC)
▸CRC Handbook of Chemistry and Physics - Aqueous Solubility of Inorganic Compounds at Various Temperatures (solubility bounds for the tabulated range)

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

The committed data file for this page is published as JSON on GitHub under CC BY 4.0.

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 · 10 wt% · 20 °C
Cited reference value	1103.4 kg/m3
Model computed	1103.25 kg/m3
Error vs reference	0.013% (tolerance 1%)

CRC Handbook of Chemistry and Physics, 97th ed.. Haynes, W.M. (ed.), CRC Handbook of Chemistry and Physics, 97th ed. (CRC Press, 2016), Concentrative Properties of Aqueous Solutions, p. 5-124: 10.0 mass % MgSO4 at 20 degC = 1.1034 g/cm3. Perry's Chemical Engineers' Handbook, 7th ed. (Magnesium Sulfate table) brackets the same point with 8% = 1.0816 and 12% = 1.1256 at 20 degC.

Full tables

Every tabulated point

Rows are temperature (°C); columns are concentration (wt% MgSO4). 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%	2	4	6	8	10	12	14	16	18	20
15	1019.5	1040.2	1061.2	1082.6	1104.3	1126.5	1149.1	1172.2	1195.8	1219.9
20	1018.6	1039.2	1060.2	1081.5	1103.3	1125.4	1148.0	1171.1	1194.8	1219.0
25	1017.4	1038.0	1058.9	1080.2	1101.9	1124.0	1146.6	1169.8	1193.4	1217.7
30	1015.9	1036.5	1057.3	1078.6	1100.3	1122.4	1145.0	1168.2	1191.9	1216.2
35	1014.2	1034.7	1055.6	1076.8	1098.4	1120.6	1143.2	1166.3	1190.0	1214.4
40	1012.3	1032.8	1053.6	1074.8	1096.4	1118.5	1141.1	1164.2	1188.0	1212.3
45	1010.3	1030.6	1051.4	1072.5	1094.1	1116.2	1138.8	1161.9	1185.7	1210.1
50	1008.0	1028.3	1049.0	1070.1	1091.7	1113.7	1136.3	1159.4	1183.2	1207.6
55	1005.6	1025.9	1046.5	1067.5	1089.1	1111.1	1133.6	1156.8	1180.5	1204.9
60	1003.0	1023.2	1043.8	1064.8	1086.3	1108.3	1130.8	1153.9	1177.7	1202.1

Dynamic viscosity — cP (mPa·s)

°C \ wt%	2	4	6	8	10	12	14	16	18	20
15	1.278	1.437	1.621	1.840	2.107	2.438	2.857	3.396	4.096	5.016
20	1.123	1.261	1.420	1.609	1.839	2.122	2.480	2.936	3.526	4.296
25	0.996	1.117	1.256	1.421	1.620	1.866	2.173	2.565	3.068	3.720
30	0.891	0.997	1.120	1.265	1.440	1.654	1.922	2.261	2.695	3.253
35	0.803	0.897	1.007	1.135	1.289	1.478	1.713	2.009	2.386	2.868
40	0.728	0.813	0.910	1.025	1.162	1.330	1.538	1.799	2.129	2.549
45	0.664	0.740	0.828	0.931	1.054	1.204	1.389	1.621	1.912	2.281
50	0.608	0.678	0.758	0.851	0.962	1.096	1.262	1.469	1.728	2.054
55	0.560	0.624	0.696	0.781	0.882	1.003	1.153	1.338	1.570	1.860
60	0.518	0.576	0.643	0.720	0.812	0.922	1.058	1.225	1.433	1.693

Specific heat capacity — J/kg·K

°C \ wt%	2	4	6	8	10	12	14	16	18	20
15	4080	3978	3881	3788	3698	3612	3529	3449	3372	3298
20	4077	3976	3880	3787	3699	3614	3531	3452	3376	3302
25	4075	3975	3880	3789	3701	3617	3535	3457	3381	3307
30	4075	3976	3882	3791	3705	3621	3540	3463	3387	3315
35	4075	3977	3884	3795	3709	3626	3547	3470	3395	3323
40	4076	3980	3888	3800	3715	3633	3554	3478	3404	3333
45	4078	3983	3892	3805	3721	3640	3562	3487	3413	3343
50	4080	3986	3897	3811	3728	3648	3571	3496	3424	3354
55	4083	3990	3902	3817	3736	3657	3581	3507	3435	3365
60	4086	3995	3908	3825	3744	3666	3591	3518	3447	3378

Typical values

Magnesium sulfate solution properties at 25 °C

At 25 °C, 4 wt% magnesium sulfate has a density of about 1038.0 kg/m³, a dynamic viscosity of about 1.117 cP and a specific heat capacity of about 3975 J/kg·K. At 25 °C, 16 wt% magnesium sulfate has a density of about 1169.8 kg/m³, a dynamic viscosity of about 2.565 cP and a specific heat capacity of about 3457 J/kg·K. At 25 °C, 20 wt% magnesium sulfate has a density of about 1217.7 kg/m³, a dynamic viscosity of about 3.720 cP and a specific heat capacity of about 3307 J/kg·K.

Limitations

Before you use these numbers

▸Laliberte (2009) aqueous-electrolyte correlation for MgSO4-water. Tabulated for 2-20 wt% over 15-60 degC, below saturation across the table (about 23 wt% MgSO4 at 15 degC). Concentrations are anhydrous MgSO4; Epsom salt is the heptahydrate (MgSO4.7H2O), 49% MgSO4 by mass, so convert before reading the table. Values are for preliminary design; verify against vendor data for critical service.
▸Values are tabulated only inside the 2–20 wt% and 15–60 °C ranges shown; the correlation is not extrapolated beyond them here.
▸Figures are for a pure magnesium sulfate–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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