Worked example
A 25 mL portion at 20 mg/mL represents 500 mg ingredient. A 75 mL portion at 5 mg/mL represents 375 mg. If the measured final volume is 100 mL, the combined 875 mg corresponds to 8.75 mg/mL.
One ingredient, two sources
Mass concentration is ingredient mass divided by solution volume, as defined by NIST. Multiplying each mg/mL concentration by its portion in mL gives its ingredient mass. Those masses can be added only when they describe the same ingredient and it is conserved; the tool does not combine concentrations for different substances.
Final volume is an explicit measurement
The calculator does not silently use A volume plus B volume. Mixtures can change volume, and a protocol may specify a different final endpoint. Enter a measured or otherwise documented final volume appropriate to the calculation. The entered figure, rather than an assumed additive volume, determines final concentration.
Concentration arithmetic only
This result does not establish chemical compatibility, stability, mixing technique or medical suitability. It does not recommend a dose, administration route or patient-specific quantity. For laboratory work, use a suitable protocol to establish identity, retained mass and final volume independently. All arithmetic stays in your browser.
Explore the related calculation
For a different starting point, try the single-stock dilution calculator or return to the main calculator. Browse the complete tool directory for this site.
Reference and corrections
The definitions and assumptions above follow these sources; the examples and calculator arithmetic are original to this page.
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