mg to mL Calculator

The formula

Converting a dose in mg to a volume in mL requires one number in between: the vial's concentration, in mg per mL. Once you know that, the conversion is a single division:

dose volume (mL) = prescribed dose (mg) ÷ concentration (mg/mL)

And the concentration itself comes from how much diluent you added:

concentration (mg/mL) = vial amount (mg) ÷ diluent volume (mL)

Worked example

A 5 mg vial reconstituted with 1 mL of diluent, for a prescribed dose of 1 mg:

1. Concentration: 5 mg ÷ 1 mL = 5 mg/mL
2. Dose volume: 1 mg ÷ 5 mg/mL = 0.2 mL

Watch the units

The most common source of error here isn't the maths -- it's mismatched units. A vial labelled in mg and a dose prescribed in mcg (1 mg = 1000 mcg) need converting to the same unit before the division above means anything. PeptOnyx Calculator handles that conversion automatically and flags it in the working, so it's never silently wrong.