Units to mg Calculator

A unit is a volume, one hundredth of a milliliter, so the milligrams in it are set by the concentration of the liquid: mg = units ÷ 100 × mg/mL. At 10 mg/mL each unit holds 0.1 mg; at 2.5 mg/mL each unit holds 0.025 mg. The converter above takes any concentration, and the quick-reference table shows common unit counts at whatever you enter.

Reversing it gives units from milligrams: units = mg ÷ mg/mL × 100. Both directions are the same relationship, and the concentration is the only number that changes between one vial and the next.

Compounded GLP-1 vials print a concentration in mg/mL, or a total and a volume that give the same thing: 5 mg/2 mL is 2.5 mg/mL, 34 mg/2 mL is 17 mg/mL. If your pharmacy dispensed a powder vial with reconstitution instructions, the concentration is the mg on the vial divided by the mL of bacteriostatic water the instructions specify, and adding more water lowers it. Switch the converter to “I mix a powder vial” to enter it that way. That mode is for prescription vials, not research-use products, which are not medicines.

Compounded semaglutide and tirzepatide are a US-only option and are not FDA-approved. The FDA has received reports of dosing errors with compounded injections, including confusion between units and milligrams, so a conversion is worth checking twice and confirming with the pharmacy.

U-100 insulin syringes come in three barrels: 30 units (0.3 mL), 50 units (0.5 mL), and 100 units (1 mL). The smaller barrels have finer markings, often half-unit lines, which matters for small semaglutide doses; the 1 mL barrel is needed for larger tirzepatide draws. A draw above 100 units does not fit any single insulin syringe, and the converter flags it. The FDA-approved pens and the Zepbound single-dose vials do not involve any of this: the pens set the dose for you, and a Zepbound vial is always 0.5 mL, drawn in full.