Weight percent

The Percent by Mass or Weight calculator computes the concentration of a solution based on the mass or weight of the solute (Ws) and solution (WS).

INSTRUCTIONS: Choose units and enter the following:

• (Ws)  Mass of Solute
• (WS)  Mass of Solution

Percent Concentration of Solution (PCS): The calculator returns the concentration as a percentage.

The Math / Science

The Percent Concentration by Mass formula is:

PCS = [Ws / WS] x 100

where:

• PCS is the percent concentration of solution by mass or weight.
• Ws is the mass or weight of the solute
• WS is the mass or weight of the solution.

Chemists frequently like to express their concentration using terms of percentage.  Percentage is parts per hundred.  There are a number of common methods for describing percent composition of solutions, such as: weight percent, volume percent, or weight/volume percent.  

This equation will calculate the Weight percentage (w/w) or more properly called the mass percent (m/m) of composition of a solution.

The Measurement of Concentration Calculator computes the percent concentration based on an amount of solute and an amount of solution.  The three functions are:

• (w/v) Weight Solute / Volume Solution Percent
• (w/w) Weight Solute / Weight Solution Percent
• (v/v) Volume Solute / Volume Solution Percent

The Math / Science

Chemists frequently like to express their concentration using terms of percentage.  Percentage is parts per hundred.  There are a number of common methods for describing percent composition of solutions, such as: weight percent, volume percent, or weight/volume percent.  These different variations of % are practical to chemists and cooks. Solids are easier to weigh, while liquids are easier to measure volume.

Examples

If you want to make a gin and tonic. You might mix 10 mLs of gin with 90 mLs of tonic. In that case you would have a 10% (v/v) solution. 

If you are making instant coffee, you might blend 10 g of Santa with 100 mLs of water. That would be a 10% (w/v) solution. 

If you had a rock that weighted 100g and contained 10g of gold, you would say that it was 10% (w/w) ore.

* Note: "weight" is really entered as mass