Acids & bases

Potassium hydroxide · KOH

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

Potassium hydroxide (KOH) is an alkali; this page gives computed density and dynamic viscosity for aqueous solutions from 5–50 wt% and 15–40 °C.

Values are computed from the Laliberté (2009) aqueous-electrolyte correlation and tabulated over 5–50 wt% and 15–40 °C.

Also known as: Caustic potash, Potassium hydrate, Potash lye
CAS number: 1310-58-3
Tabulated range: 5–50 wt% · 15–40 °C
Properties: Density · Dynamic viscosity · Specific gravity

At 8 wt% · 20 °C

reference snapshot

Density: 1071.8kg/m³
Density: 1.0718g/cm³
Specific gravity: 1.074
Viscosity: 1.194cP

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 5–50 wt% and 15–40 °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 5–50 wt% and 15–40 °C range.

Concentration28 wt%

Temperature20 °C

Density: 1268.5 kg/m³
Density: 1.2685 g/cm³
Specific gravity: 1.271
Dynamic viscosity: 2.065 cP

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

Why it matters

What the numbers tell you

At 8 wt% and 20 °C, aqueous potassium hydroxide has a density of about 1072 kg/m³ (1.072 g/cm³) — roughly 1.07× the density of water. It also has a dynamic viscosity of about 1.194 cP, against roughly 1 cP for water at the same temperature. Those differences carry straight into volume-to-mass conversions, pump and pipe sizing.

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% KOH	°C	Density kg/m³	SG	Viscosity cP
10	20	1090.4	1.092	1.246
30	20	1289.2	1.292	2.219
45	20	1453.8	1.456	5.658
50	20	1512.3	1.515	8.539

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) - Table 2-78 Potassium Hydroxide density, from International Critical Tables, Vol. III, p. 86
▸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 · 8 wt% · 15 °C
Cited reference value	1073 kg/m3
Model computed	1072.91 kg/m3
Error vs reference	0.009% (tolerance 1%)

Perry's Chemical Engineers' Handbook, 7th ed. (from International Critical Tables). Perry, R.H. & Green, D.W. (eds.), Perry's Chemical Engineers' Handbook, 7th ed., Table 2-78 Potassium Hydroxide (KOH) (data from International Critical Tables, Vol. III, p. 86): 8 wt% KOH, d15/4 = 1.0730 g/cm3. The 15 degC basis is the source table's reference temperature; the check is evaluated at 15 degC, inside the tabulated range.

Full tables

Every tabulated point

Rows are temperature (°C); columns are concentration (wt% KOH). 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
15	1044.9	1091.8	1139.8	1188.9	1239.4	1291.3	1344.6	1399.6	1456.3	1514.9
20	1043.8	1090.4	1138.2	1187.2	1237.5	1289.2	1342.4	1397.2	1453.8	1512.3
25	1042.4	1088.8	1136.4	1185.1	1235.2	1286.8	1339.8	1394.5	1451.0	1509.5
30	1040.8	1087.0	1134.3	1182.8	1232.8	1284.1	1337.0	1391.6	1448.0	1506.4
35	1038.9	1084.9	1132.0	1180.3	1230.0	1281.2	1334.0	1388.5	1444.8	1503.2
40	1036.9	1082.6	1129.4	1177.6	1227.1	1278.1	1330.8	1385.2	1441.5	1499.8

Dynamic viscosity — cP (mPa·s)

°C \ wt%	5	10	15	20	25	30	35	40	45	50
15	1.267	1.412	1.579	1.786	2.072	2.515	3.260	4.538	6.638	10.31
20	1.117	1.246	1.395	1.580	1.833	2.219	2.861	3.939	5.658	8.539
25	0.994	1.110	1.245	1.410	1.636	1.977	2.535	3.457	4.882	7.178
30	0.891	0.997	1.119	1.269	1.472	1.775	2.266	3.063	4.260	6.113
35	0.805	0.902	1.013	1.150	1.334	1.606	2.042	2.736	3.753	5.267
40	0.732	0.821	0.923	1.049	1.216	1.463	1.852	2.463	3.334	4.585

Typical values

Potassium hydroxide solution properties at 25 °C

At 25 °C, 10 wt% potassium hydroxide has a density of about 1088.8 kg/m³ and a dynamic viscosity of about 1.110 cP. At 25 °C, 45 wt% potassium hydroxide has a density of about 1451.0 kg/m³ and a dynamic viscosity of about 4.882 cP. At 25 °C, 50 wt% potassium hydroxide has a density of about 1509.5 kg/m³ and a dynamic viscosity of about 7.178 cP.

Limitations

Before you use these numbers

▸Laliberte (2009) aqueous-electrolyte correlation for KOH-water, density and viscosity. Tabulated for 5-50 wt% over 15-40 degC. The 40 degC ceiling is the top of the correlation's fitted KOH viscosity data, and the 15 degC floor keeps the strong 50 wt% liquor below saturation across the table (saturation is about 50 wt% KOH near 5 degC, rising with temperature). Heat capacity is not tabulated: the correlation's KOH heat-capacity data does not reach the 50 wt% ceiling of this table, so it is omitted rather than extrapolated. Concentrations are KOH by mass; commercial caustic potash is supplied mainly as 45 and 50 wt% liquor. Values are for preliminary design; verify against vendor data for critical service.
▸Values are tabulated only inside the 5–50 wt% and 15–40 °C ranges shown; the correlation is not extrapolated beyond them here.
▸Figures are for a pure potassium hydroxide–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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