500 mcg to units on an insulin syringe
500 mcg to units depends on how strong your vial is. At 2.5 mg/mL, 500 mcg (0.5 mg) is 20 units on a U-100 insulin syringe. Use the calculator for your own vial and water, or find your mix in the chart below.
Units to draw
20units
Draw to the 20-unit mark on a U-100 syringe.
- Dose
- 500 mcg (0.5 mg)
- Volume
- 0.2 mL
- Concentration
- 2,500 mcg/mL (2.5 mg/mL)
- Per unit
- 25 mcg (0.025 mg)
- Full doses in vial
- 10
Show the math
- Convert the vial amount to mcgmg × 1,000 = mcg5 mg × 1,000 = 5,000 mcg
- Concentrationvial (mcg) ÷ water (mL) = mcg per mL5,000 mcg ÷ 2 mL = 2,500 mcg/mL (2.5 mg/mL)
- Volume to drawdose (mcg) ÷ concentration (mcg/mL) = mL500 mcg ÷ 2,500 mcg/mL = 0.2 mL
- Units to drawmL × units per mL = units0.2 mL × 100 units/mL = 20 units
- Amount in each unitmcg per mL ÷ units per mL = mcg per unit2,500 mcg/mL ÷ 100 units/mL = 25 mcg per unit (0.025 mg)
- Doses in the vialvial (mcg) ÷ dose (mcg), rounded down5,000 mcg ÷ 500 mcg = 10 full doses
500 mcg to units chart
Units on a U-100 syringe for 500 mcg at common vial sizes and water volumes, calculated by this site. A dash means 500 mcg is more than the whole vial.
| Vial | 1 mL water | 2 mL water | 3 mL water |
|---|---|---|---|
| 2 mg | 25 units | 50 units | 75 units |
| 5 mg | 10 units | 20 units | 30 units |
| 10 mg | 5 units | 10 units | 15 units |
| 15 mg | 3.3 units | 6.7 units | 10 units |
| 20 mg | 2.5 units | 5 units | 7.5 units |
| 30 mg | 1.7 units | 3.3 units | 5 units |
Across these mixes, 500 mcg measures between 2.5 and 75 units where it fits one syringe. In 1 mix it is under 2 units, too small to read reliably.
500 mcg to units by concentration
If you already know your concentration in mg per mL, read it straight from this table.
| Concentration | Units (U-100) | Volume |
|---|---|---|
| 0.5 mg/mL (500 mcg/mL) | 100 units | 1 mL |
| 1 mg/mL (1,000 mcg/mL) | 50 units | 0.5 mL |
| 2 mg/mL (2,000 mcg/mL) | 25 units | 0.25 mL |
| 2.5 mg/mL (2,500 mcg/mL) | 20 units | 0.2 mL |
| 5 mg/mL (5,000 mcg/mL) | 10 units | 0.1 mL |
| 10 mg/mL (10,000 mcg/mL) | 5 units | 0.05 mL |
How do you convert 500 mcg to units?
Divide the amount in mcg by ten times your concentration in mg/mL: units = mcg ÷ (10 × mg/mL). For 500 mcg at 2.5 mg/mL that is 500 ÷ (10 × 2.5) = 20 units.
Your concentration is the peptide in the vial divided by the water you added: a 5 mg vial with 2 mL of water is 2.5 mg/mL. The reconstitution math guide shows every step.
Which syringe fits 500 mcg?
With a 5 mg vial and 2 mL of water, 500 mcg is 20 units, which fits a 0.3 mL (30-unit) U-100 syringe. Smaller barrels have wider spacing between marks, so they are easier to read for small amounts.
See the insulin syringe units chart for how each syringe size is marked.
Frequently asked questions
How many units is 500 mcg?
It depends on the concentration of your vial. At 2.5 mg/mL, 500 mcg is 20 units on a U-100 syringe; at 5 mg/mL it is 10 units.
Is 500 mcg the same number of units on a 30, 50 and 100-unit syringe?
Yes, if they are all U-100 syringes. Every U-100 syringe holds 100 units per mL; the barrel size only changes how many units fit and how easy the marks are to read.
How many units is 500 mcg on a U-40 or U-50 syringe?
Fewer units, because each unit holds more liquid. With a 5 mg vial and 2 mL of water, 500 mcg is 20 units on U-100, 10 on U-50 and 8 on U-40.
What is 500 mcg in mg?
500 mcg is 0.5 mg. There are 1,000 mcg in 1 mg.