Syringe Unit Converter

Enter a concentration and syringe scale, then type a value into any one field below — units, ml, mg, or mcg. This computes the other three from what you entered; it is an educational math tool, not a source of dosing instructions.

Computed from the values you entered above.

Common unit / ml / mg conversions

Computed on a U-100 syringe scale (100 units per ml).
ConcentrationUnitsmlmgmcg
2.5 mg/ml10 units0.1 ml0.25 mg250 mcg
2.5 mg/ml20 units0.2 ml0.5 mg500 mcg
5 mg/ml10 units0.1 ml0.5 mg500 mcg
5 mg/ml20 units0.2 ml1 mg1000 mcg
5 mg/ml50 units0.5 ml2.5 mg2500 mcg
10 mg/ml10 units0.1 ml1 mg1000 mcg
10 mg/ml20 units0.2 ml2 mg2000 mcg
10 mg/ml50 units0.5 ml5 mg5000 mcg
20 mg/ml10 units0.1 ml2 mg2000 mcg
25 mg/ml20 units0.2 ml5 mg5000 mcg
50 mg/ml10 units0.1 ml5 mg5000 mcg

Frequently asked questions

How many units are in 1 ml?

It depends on the syringe scale printed on the barrel: a U-100 syringe marks 100 units per ml, a U-40 syringe marks 40 units per ml, and a U-30 syringe marks 30 units per ml. The "units" scale is just a finer way of marking fractions of a milliliter — it isn't a separate physical quantity.

How do I convert mg to ml for a syringe?

Divide the mass (in mg) by the concentration (in mg/ml) to get the volume in ml. For example, 5 mg at a 5 mg/ml concentration computes to 1 ml. This calculator does that division for you, then also reads the volume off any syringe scale as units.

What's the difference between U-100 and U-40 syringes?

The number after "U" is how many units are printed across 1 ml of that syringe's barrel — U-100 has 100 unit marks per ml, U-40 has 40. The same physical volume reads as a different unit count depending on the scale, so drawing to "20 units" means something different on each syringe. Always match the syringe scale you select in this calculator to the syringe scale printed on the barrel you're using.

How many units is X mg?

That depends on the concentration (mg/ml) and the syringe scale. This calculator converts a mg amount to ml (mg ÷ concentration), then to units for the syringe scale you pick (ml × units-per-ml). Enter your concentration and syringe scale above, then type the mg amount to see the computed unit value.

How do I convert units to mg?

Convert units to ml first (units ÷ units-per-ml for the syringe scale), then ml to mg by multiplying by the concentration (mg/ml). This calculator runs both steps automatically — enter a value in the units field and the mg field updates from the concentration you set.

What is mcg and how does it relate to mg?

Mcg (micrograms) and mg (milligrams) are both mass units: 1 mg equals 1,000 mcg. This calculator shows both so you can read the same computed mass in whichever unit your reference material uses.

Why do units, ml, and mg give different numbers for the same draw?

Units, ml, and mg measure the same physical amount in three different systems — a syringe-scale count, a volume, and a mass. They agree with each other once a concentration (mg/ml) and syringe scale are fixed, which is exactly what this calculator's inputs supply. None of the three numbers is more “correct” than the others; they're just different units for the same computed quantity.