Tool
Dilution helper
Given a stock concentration, target concentration, and final volume, calculates the volume of stock drug and diluent you need. Works for any drug.
Dilution helper — standalone
Work out how many mL of stock drug and diluent to combine for any target concentration. Stock is pre-filled for standalone; change it if you're using a different vial.
Draw up
4.00 mL stock drug
+ 46.00 mL diluent
Combine to a final volume of 50.0 mL. Gives a concentration of 1000.0 µg/mL.
Formula
$$C_1 V_1 = C_2 V_2$$
Stock concentration × stock volume = final concentration × final volume
$$V_1 = \frac{C_2 \times V_2}{C_1} = \frac{ 1000.0 \times 50.0 }{ 12500.0 } = 4.00\,\text{mL}$$