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Compute the antibiotic stock volume for a target working concentration with C₁V₁ = C₂V₂, supporting mg/mL, µg/mL, g/L, ng/mL and × fold notation.
Execution
Fill in the form, run the tool, and review the result in one place.
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Tool usage guide
Calculate the antibiotic stock volume needed to reach a target working concentration with the C₁V₁ = C₂V₂ formula. Enter stock and working concentrations in mg/mL, µg/mL, g/L, ng/mL or × fold units plus the final medium volume to receive the stock volume in mL and µL, the remaining medium volume, and the dilution factor.
Background
A 100 mL bottle of LB broth must be supplemented with ampicillin from a frozen 100 mg/mL stock.
Problem
Find the exact microlitre volume of stock that yields 50 µg/mL without unit-conversion errors.
How to use
Set stock concentration to 100 mg/mL, working concentration to 50 µg/mL and final volume to 100 mL.
Outcome
Add 0.05 mL (50 µL) of stock to 99.95 mL medium (1:2000 dilution).
Background
A 1000× antibiotic concentrate must be diluted into 500 mL of selective medium.
Problem
Determine how much 1000× stock produces a 1× working concentration.
How to use
Enter stock 1000 fold, working 1 fold and final volume 500 mL.
Outcome
Add 0.5 mL (500 µL) of stock to 499.5 mL medium (1:1000 dilution).
It uses C₁V₁ = C₂V₂ so that stock volume V₁ equals working concentration times final volume divided by stock concentration.
mg/mL, µg/mL, g/L, ng/mL and × (fold concentration) for both stock and working values.
Yes. Units are converted automatically, so a 100 mg/mL stock can be paired with a 50 µg/mL working concentration.
Final volume accepts µL, mL or L. Results always report stock volume in both mL and µL.
Common values include ampicillin 50–100 µg/mL and kanamycin 25–50 µg/mL; follow your own protocol.