Mass Percent Calculator
Switch between calculating mass percentage from component and total mass, or determine how much component you need for a desired percent.
Mass percent
2.5%
How to Use This Calculator
Select the conversion mode
Choose whether you want to compute mass percent or determine how much component is needed.
Enter masses or target percent
Provide the known values. Units cancel out, so grams, kilograms, or pounds all work if consistent.
Read the result
The calculator returns either percent composition or the required component mass for the batch.
Scale as needed
Adjust inputs to scale recipes or formulations while maintaining the same mass fraction.
Formula
mass % = (m_component / m_total) × 100
m_component = (mass % / 100) × m_total
Mass percent is also called weight percent (w/w). It expresses the fraction of a component relative to the total mass of the mixture.
Example
To prepare 500 g of a 6% NaCl solution: m_component = 0.06 × 500 = 30 g salt, and 470 g solvent.
Full Description
Mass percent (weight percent) is the ratio of a component’s mass to the total mass of a mixture, multiplied by 100. It is widely used in chemistry, cosmetics, food science, and materials formulation.
This calculator accommodates two common tasks: computing percent composition from measured masses and determining how much component to add for a target percent formulation. Switching between modes keeps workflows efficient when scaling recipes or translating between specs and practical amounts.
Frequently Asked Questions
Is mass percent the same as weight percent?
Yes. Weight percent (w/w) and mass percent describe the same quantity.
Can I use different units?
Mass percent is unitless. Just make sure component and total mass use the same unit before computing.
How does this differ from volume percent?
Mass percent is based on mass, whereas volume percent uses volumes. Choose the metric that matches your specification.
What if components add up to more than total mass?
That indicates inconsistent data. Verify that the total mass equals the sum of all component masses.
Can I calculate solvent mass?
Yes. Subtract the component mass from the total mass to get the mass of the remainder (often the solvent).