The calculator is a unit converter, not a dose selector.
Every result comes from three user-supplied values and one syringe scale. This page shows the full formula, assumptions, worked example, and limits so the output can be checked independently.
The formula
- 1
Concentration
vial amount in mg ÷ liquid volume in mL = mg/mL
- 2
Convert micrograms when needed
instructed mcg ÷ 1,000 = instructed mg
- 3
Liquid volume
instructed mg ÷ concentration in mg/mL = mL
- 4
Syringe-unit conversion
mL × selected syringe units per mL = displayed units
Worked arithmetic example
This is deliberately compound-neutral and is not a preparation recommendation.
10 mg ÷ 2 mL = 5 mg/mL
If an independently supplied instruction were 1 mg, the volume would be 1 ÷ 5 = 0.2 mL. On a scale defined as 100 units per mL, 0.2 × 100 = 20 displayed units.
Changing any input changes the result. The example does not establish that a vial should contain 10 mg, use 2 mL, or be used at a 1 mg amount.
Assumptions
- The vial label and liquid volume are accurate.
- The instructed amount is entered in the correct mg or mcg unit.
- The selected syringe scale matches the physical syringe.
- The product is intended to be prepared in the way described by its instructions.
Do not use the result when
- The label, concentration, units, or product form are unclear.
- The result exceeds the selected syringe capacity.
- The product instructions conflict with any entered value.
- You are using the calculator to choose an amount or alter a preparation.
Private by default
The web calculator runs in your browser. The worksheet does not require an account and does not send the entered vial, liquid, or amount values to a calculation API.