Concentration Calculator 2026-27 — GlobalCalc

GlobalCalc

Inputs

Given as

Value

Molar mass

g/mol

Results update as you type

Results

Molarity

1 mol/L

Grams per litre—

Percent w/v—

Parts per million—

Milligrams per litre—

Millimolar—

Mass in that volume (g)—

Moles in that volume—

Reviewed September 2026. Chemistry is the same in every country: SI and laboratory units throughout.

All calculations run 100% in your browser. The calculator code does not submit your figures to GlobalCalc to obtain a result.

About concentration

Method

How the concentration calculator works

Concentration is amount divided by volume, but "amount" can be moles, grams or a percentage, and the conversions all run through the molar mass.

Mass concentration in g/L divided by molar mass gives molarity. Percent w/v is grams per 100 mL, so 1% w/v is 10 g/L. And ppm for a dilute aqueous solution is simply mg/L, because a litre of water weighs a kilogram.

Formula: M = (g/L) / molar mass; 1% w/v = 10 g/L; 1 ppm ≈ 1 mg/L

Data

Worked examples

Inputs	Molarity	Note
58.44 g/L of NaCl	1 mol/L	exactly 1 M
0.9% saline	0.154004 mol/L	0.154 M — physiological saline
10 ppm	0.000171 mol/L	0.171 mM

FAQ

Frequently asked questions

How do I convert g/L to molarity?

Divide by the molar mass. 58.44 g/L of NaCl is exactly 1 mol/L because that is its molar mass.

What is percent w/v?

Grams of solute per 100 mL of solution. 1% w/v is 10 g/L.

Is ppm the same as mg/L?

For dilute aqueous solutions, yes, because a litre of water weighs a kilogram. For other solvents or concentrated solutions the density differs and they diverge.

What is physiological saline?

0.9% w/v NaCl — 9 g/L, or 0.154 M. It is roughly isotonic with blood.

Why so many units?

Different fields need different things. Chemistry wants moles for reactions, medicine wants mass for dosing, and environmental work wants ppm for trace amounts.

Sources

Where these figures come from

IUPAC — Standard atomic weights (2021 conventional values) — the molar-mass table
NIST — CODATA 2018 fundamental physical constants — Avogadro constant, gas constant, speed of light
NIST Chemistry WebBook — thermochemical data
Royal Society of Chemistry — the UK chemistry professional body

Last checked: September 2026. Atomic masses are the IUPAC conventional values; constants are CODATA 2018; equations are the standard textbook forms.