Syringe Calculator

This calculator is a unit-conversion reference. Use it after you know the vial concentration and the syringe format you are reading.

For a standard U-100 insulin syringe, 100 units equals 1 mL and each small notch is 0.01 mL. Always check the barrel label before drawing a dose, because other syringe formats use different capacities or graduation patterns.

Use the output as a math check, then follow the product instructions or prescriber directions for the actual dose.

The markings on the syringe are volume markings, not a prescription. That makes them useful for vial-based products, but only if you are working from the correct concentration.

If you are using a compounded vial, write the concentration on the label before you inject. That makes it easier to reverse-check the math later and reduces the chance of a measurement error.

For branded GLP-1 pens, use the pen instructions instead of a syringe calculator. For vial-based products, use the vial concentration and the syringe markings together.

This page does not tell you whether a medication is appropriate for self-administration. It only helps you convert between units once a clinician or pharmacy has already given you an injection plan.

If the syringe label does not clearly say U-100, do not assume the scale is the same. Confirm the device before drawing anything.

When in doubt, pause and check the prescription label or ask the pharmacist. The safest dose is the one that matches the actual device in your hand.