# Mass Percent Calculator

Free mass percent calculator. Calculate weight percent of solute in solution using mass% = (mass solute / mass solution) × 100.

## What this calculates

Calculate the mass percent (weight percent) of a solution. Mass percent is the ratio of solute mass to total solution mass, expressed as a percentage.

## Inputs

- **Solve For** — options: Mass Percent (%), Mass of Solute, Mass of Solution — Select what to calculate.
- **Mass of Solute** (g) — min 0 — Mass of the dissolved substance in grams.
- **Mass of Solution** (g) — min 0 — Total mass of the solution (solute + solvent) in grams.
- **Mass Percent** (%) — min 0, max 100 — Mass percent of the solute.

## Outputs

- **Result** — The calculated value.
- **Unit** — formatted as text — Unit of the result.
- **Mass of Solvent** (g) — Mass of solvent (solution - solute).
- **Formula** — formatted as text — Calculation steps.

## Frequently Asked Questions

**Q: What is mass percent?**

A: Mass percent (weight percent, w/w%) is the mass of solute divided by the total mass of solution, multiplied by 100. For example, a 5% NaCl solution contains 5 g of NaCl per 100 g of solution.

**Q: How is mass percent different from molarity?**

A: Mass percent uses mass ratios and is temperature-independent. Molarity uses moles per liter of solution and changes with temperature (since volume changes). Mass percent does not require knowing the molar mass.

**Q: Is mass of solution the same as mass of solvent?**

A: No. Mass of solution = mass of solute + mass of solvent. For example, dissolving 10 g NaCl in 90 g water gives a 100 g solution with 10% mass percent.

**Q: What are common mass percent values?**

A: Common examples: household bleach is ~5% NaOCl, vinegar is ~5% acetic acid, saline solution is 0.9% NaCl, rubbing alcohol is 70% isopropanol.

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Source: https://vastcalc.com/calculators/chemistry/mass-percent
Category: Chemistry
Last updated: 2026-04-21