Salts & brines

Potassium nitrate · KNO3

Name: Potassium nitrate (KNO3) aqueous solution properties
Creator: ProcessConvert
License: https://creativecommons.org/licenses/by/4.0/

Potassium nitrate (KNO3) is a salt; this page gives computed density, dynamic viscosity and specific heat capacity for aqueous solutions from 2–18 wt% and 15–60 °C.

Values are computed from the Laliberté (2009) aqueous-electrolyte correlation and tabulated over 2–18 wt% and 15–60 °C.

Also known as: Saltpetre, Niter, Nitre
CAS number: 7757-79-1
Tabulated range: 2–18 wt% · 15–60 °C
Properties: Density · Dynamic viscosity · Specific heat capacity · Specific gravity

At 10 wt% · 20 °C

reference snapshot

Density: 1062.6kg/m³
Density: 1.0626g/cm³
Specific gravity: 1.065
Viscosity: 0.971cP
Specific heat: 3777J/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 2–18 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 2–18 wt% and 15–60 °C range.

Concentration10 wt%

Temperature20 °C

Density: 1062.6 kg/m³
Density: 1.0626 g/cm³
Specific gravity: 1.065
Dynamic viscosity: 0.971 cP
Specific heat: 3777 J/kg·K

Density (kg/m³) vs wt% KNO3 at 20 °C — Potassium nitrate.

Why it matters

What the numbers tell you

At 10 wt% and 20 °C, aqueous potassium nitrate has a density of about 1063 kg/m³ (1.063 g/cm³) — roughly 1.06× the density of water. It also has a dynamic viscosity of about 0.971 cP, against roughly 1 cP for water at the same temperature, and a specific heat of about 3.78 kJ/kg·K, about 90% 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% KNO3	°C	Density kg/m³	SG	Viscosity cP	Sp. heat J/kg·K
4	20	1023.3	1.025	0.984	4006
10	20	1062.6	1.065	0.971	3777
14	20	1089.9	1.092	0.974	3637
18	20	1118.2	1.120	0.984	3504

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 - Concentrative Properties of Aqueous Solutions (density and viscosity at 20 degC; primary data Wolf, A.V., 1966)
▸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	1062.7 kg/m3
Model computed	1062.57 kg/m3
Error vs reference	0.012% (tolerance 1%)

CRC Handbook of Chemistry and Physics - Concentrative Properties of Aqueous Solutions. CRC Handbook of Chemistry and Physics, Concentrative Properties of Aqueous Solutions (all data at 20 degC; primary data Wolf, A.V., Aqueous Solutions and Body Fluids, Hoeber, 1966), potassium nitrate: 10.0 mass % at 20 degC = 1.0627 g/cm3.

Full tables

Every tabulated point

Rows are temperature (°C); columns are concentration (wt% KNO3). 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
15	1011.7	1024.5	1037.5	1050.8	1064.2	1077.9	1091.9	1106.0	1120.5
20	1010.7	1023.3	1036.2	1049.3	1062.6	1076.1	1089.9	1103.9	1118.2
25	1009.4	1021.9	1034.6	1047.5	1060.7	1074.1	1087.8	1101.6	1115.8
30	1007.8	1020.2	1032.8	1045.6	1058.7	1072.0	1085.5	1099.2	1113.2
35	1006.1	1018.4	1030.9	1043.6	1056.5	1069.7	1083.1	1096.7	1110.6
40	1004.2	1016.4	1028.7	1041.4	1054.2	1067.3	1080.6	1094.1	1107.9
45	1002.1	1014.2	1026.5	1039.0	1051.7	1064.7	1077.9	1091.4	1105.1
50	999.8	1011.8	1024.0	1036.5	1049.2	1062.1	1075.2	1088.6	1102.3
55	997.4	1009.3	1021.5	1033.9	1046.5	1059.3	1072.4	1085.8	1099.4
60	994.9	1006.7	1018.8	1031.1	1043.7	1056.5	1069.5	1082.8	1096.4

Dynamic viscosity — cP (mPa·s)

°C \ wt%	2	4	6	8	10	12	14	16	18
15	1.125	1.113	1.103	1.096	1.091	1.089	1.090	1.092	1.097
20	0.992	0.984	0.977	0.973	0.971	0.971	0.974	0.978	0.984
25	0.883	0.878	0.874	0.871	0.871	0.873	0.877	0.882	0.889
30	0.793	0.789	0.787	0.786	0.788	0.791	0.795	0.801	0.809
35	0.716	0.714	0.714	0.714	0.717	0.720	0.726	0.732	0.741
40	0.652	0.651	0.651	0.653	0.656	0.660	0.666	0.673	0.682
45	0.596	0.596	0.597	0.599	0.603	0.608	0.614	0.621	0.630
50	0.548	0.549	0.550	0.553	0.557	0.562	0.569	0.576	0.585
55	0.506	0.507	0.510	0.513	0.517	0.523	0.529	0.537	0.545
60	0.469	0.471	0.474	0.477	0.482	0.487	0.494	0.501	0.510

Specific heat capacity — J/kg·K

°C \ wt%	2	4	6	8	10	12	14	16	18
15	4093	4006	3926	3850	3777	3706	3638	3571	3506
20	4091	4006	3926	3850	3777	3706	3637	3570	3504
25	4090	4006	3926	3850	3777	3706	3637	3569	3504
30	4090	4006	3927	3851	3777	3706	3637	3569	3503
35	4090	4007	3928	3852	3778	3706	3637	3569	3503
40	4091	4008	3929	3853	3779	3707	3638	3570	3504
45	4092	4009	3930	3854	3780	3708	3638	3570	3504
50	4093	4011	3932	3855	3781	3710	3640	3571	3505
55	4095	4012	3934	3857	3783	3711	3641	3573	3506
60	4097	4015	3936	3859	3785	3713	3643	3575	3508

Typical values

Potassium nitrate solution properties at 25 °C

At 25 °C, 4 wt% potassium nitrate has a density of about 1021.9 kg/m³, a dynamic viscosity of about 0.878 cP and a specific heat capacity of about 4006 J/kg·K. At 25 °C, 14 wt% potassium nitrate has a density of about 1087.8 kg/m³, a dynamic viscosity of about 0.877 cP and a specific heat capacity of about 3637 J/kg·K. At 25 °C, 18 wt% potassium nitrate has a density of about 1115.8 kg/m³, a dynamic viscosity of about 0.889 cP and a specific heat capacity of about 3504 J/kg·K.

Limitations

Before you use these numbers

▸Laliberte (2009) aqueous-electrolyte correlation for KNO3-water. Tabulated for 2-18 wt% over 15-60 degC. Potassium nitrate solubility climbs steeply with temperature, from about 21 wt% at 15 degC to far higher when hot; the 18 wt% ceiling keeps the cold end of the table below saturation. Dilute potassium nitrate is slightly less viscous than water (a known electrolyte effect). Concentrations are KNO3 by mass. Values are for preliminary design; verify against vendor data for critical service.
▸Values are tabulated only inside the 2–18 wt% and 15–60 °C ranges shown; the correlation is not extrapolated beyond them here.
▸Figures are for a pure potassium nitrate–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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