Acids & bases

Formic acid · HCOOH

Name: Formic acid (HCOOH) aqueous solution properties
Creator: ProcessConvert
License: https://creativecommons.org/licenses/by/4.0/

Formic acid (HCOOH) is an acid; this page gives computed density and dynamic viscosity for aqueous solutions from 5–60 wt% and 15–55 °C.

Values are computed from the Laliberté (2009) aqueous-electrolyte correlation and tabulated over 5–60 wt% and 15–55 °C.

Also known as: Methanoic acid, Aminic acid
CAS number: 64-18-6
Tabulated range: 5–60 wt% · 15–55 °C
Properties: Density · Dynamic viscosity · Specific gravity

At 20 wt% · 20 °C

reference snapshot

Density: 1047.2kg/m³
Density: 1.0472g/cm³
Specific gravity: 1.049
Viscosity: 1.120cP

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 15–55 °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 15–55 °C range.

Concentration33 wt%

Temperature20 °C

Density: 1078.1 kg/m³
Density: 1.0781 g/cm³
Specific gravity: 1.080
Dynamic viscosity: 1.210 cP

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

Why it matters

What the numbers tell you

At 20 wt% and 20 °C, aqueous formic acid has a density of about 1047 kg/m³ (1.047 g/cm³) — roughly 1.05× the density of water. It also has a dynamic viscosity of about 1.120 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% HCOOH	°C	Density kg/m³	SG	Viscosity cP
10	20	1022.8	1.025	1.058
30	20	1071.0	1.073	1.188
50	20	1117.3	1.119	1.339
60	20	1139.6	1.142	1.423

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)

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 · 20 wt% · 20 °C
Cited reference value	1046.7 kg/m3
Model computed	1047.15 kg/m3
Error vs reference	0.043% (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), formic acid: 20.0 mass % at 20 degC = 1.0467 g/cm3.

Full tables

Every tabulated point

Rows are temperature (°C); columns are concentration (wt% HCOOH). 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
15	1011.8	1024.4	1036.9	1049.4	1061.7	1074.0	1086.1	1098.0	1109.9	1121.6	1133.1	1144.5
20	1010.6	1022.8	1035.0	1047.2	1059.2	1071.0	1082.8	1094.5	1106.0	1117.3	1128.5	1139.6
25	1009.1	1021.1	1032.9	1044.7	1056.4	1068.0	1079.5	1090.8	1102.0	1113.0	1124.0	1134.7
30	1007.4	1019.1	1030.7	1042.2	1053.6	1064.8	1076.0	1087.1	1098.0	1108.8	1119.4	1129.9
35	1005.5	1016.9	1028.2	1039.4	1050.6	1061.6	1072.5	1083.3	1094.0	1104.5	1114.9	1125.1
40	1003.4	1014.6	1025.6	1036.6	1047.5	1058.3	1068.9	1079.5	1089.9	1100.2	1110.4	1120.4
45	1001.2	1012.1	1022.9	1033.6	1044.3	1054.8	1065.3	1075.6	1085.9	1096.0	1106.0	1115.8
50	998.8	1009.5	1020.1	1030.6	1041.0	1051.4	1061.6	1071.8	1081.8	1091.7	1101.6	1111.3
55	996.2	1006.7	1017.1	1027.4	1037.7	1047.8	1057.9	1067.9	1077.8	1087.6	1097.2	1106.8

Dynamic viscosity — cP (mPa·s)

°C \ wt%	5	10	15	20	25	30	35	40	45	50	55	60
15	1.166	1.197	1.229	1.263	1.298	1.335	1.374	1.414	1.456	1.499	1.544	1.590
20	1.029	1.058	1.089	1.120	1.154	1.188	1.224	1.261	1.299	1.339	1.381	1.423
25	0.916	0.944	0.973	1.002	1.033	1.065	1.098	1.133	1.168	1.205	1.243	1.283
30	0.822	0.848	0.875	0.903	0.932	0.962	0.993	1.025	1.058	1.092	1.127	1.164
35	0.743	0.768	0.793	0.819	0.846	0.874	0.903	0.933	0.963	0.995	1.027	1.061
40	0.676	0.699	0.723	0.748	0.773	0.799	0.826	0.853	0.882	0.911	0.942	0.973
45	0.618	0.640	0.663	0.686	0.710	0.734	0.759	0.785	0.811	0.839	0.867	0.896
50	0.568	0.589	0.610	0.632	0.654	0.677	0.701	0.725	0.750	0.775	0.802	0.829
55	0.525	0.545	0.565	0.585	0.606	0.628	0.650	0.672	0.696	0.720	0.745	0.770

Typical values

Formic acid solution properties at 25 °C

At 25 °C, 10 wt% formic acid has a density of about 1021.1 kg/m³ and a dynamic viscosity of about 0.944 cP. At 25 °C, 50 wt% formic acid has a density of about 1113.0 kg/m³ and a dynamic viscosity of about 1.205 cP. At 25 °C, 60 wt% formic acid has a density of about 1134.7 kg/m³ and a dynamic viscosity of about 1.283 cP.

Limitations

Before you use these numbers

▸Laliberte (2009) aqueous-electrolyte correlation for formic acid-water, density and viscosity. Tabulated for 5-60 wt% over 15-55 degC, within the correlation's fitted window. Formic acid is miscible with water in all proportions; the table is capped at 60 wt% to stay within the concentration range carried by the cited reference density data. Heat capacity is not tabulated: the correlation's formic-acid heat-capacity data covers only dilute solutions (to about 12 wt%), so it is omitted rather than extrapolated. Values are for preliminary design; verify against vendor data for critical service.
▸Values are tabulated only inside the 5–60 wt% and 15–55 °C ranges shown; the correlation is not extrapolated beyond them here.
▸Figures are for a pure formic 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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