mcg to Units Conversion Chart

Quick reference tables for U-100 insulin syringes (100 units = 1 mL). The core rule: units = mcg ÷ (concentration in mcg/mL) × 100.

Table 1 — mcg per syringe unit (vial size × diluent)

Find your vial size and how much diluent was added; the cell shows how many mcg one unit on the syringe contains.

Vial ↓ / Diluent →	0.5 mL	1 mL	1.5 mL	2 mL	2.5 mL	3 mL
1 mg	20	10	6.7	5	4	3.3
2 mg	40	20	13.3	10	8	6.7
2.5 mg	50	25	16.7	12.5	10	8.3
5 mg	100	50	33.3	25	20	16.7
10 mg	200	100	66.7	50	40	33.3
15 mg	300	150	100	75	60	50
20 mg	400	200	133.3	100	80	66.7

Concentration in mcg/mL = vial mcg ÷ diluent mL (e.g. 5 mg in 2 mL = 2,500 mcg/mL). Cells over 100 units exceed a 1 mL syringe and are marked "—".

Amount ↓ / mcg/mL →	500	1,000	2,000	2,500	3,333	5,000	10,000
50 mcg	10	5	2.5	2	1.5	1	0.5
100 mcg	20	10	5	4	3	2	1
200 mcg	40	20	10	8	6	4	2
250 mcg	50	25	12.5	10	7.5	5	2.5
300 mcg	60	30	15	12	9	6	3
500 mcg	100	50	25	20	15	10	5
750 mcg	—	75	37.5	30	22.5	15	7.5
1,000 mcg	—	100	50	40	30	20	10
2,000 mcg	—	—	100	80	60	40	20
2,500 mcg	—	—	—	100	75	50	25
5,000 mcg	—	—	—	—	—	100	50

Rows are round reference numbers for arithmetic, not suggested amounts. Not in the table? Use the dose calculator.

1 mg = 1,000 mcg · 1 mcg = 0.001 mg
U-100 syringe: 1 unit = 0.01 mL · 10 units = 0.1 mL · 100 units = 1 mL
mcg per unit = concentration (mcg/mL) ÷ 100
U-40 syringes (veterinary) are different: 40 units = 1 mL. These charts do not apply to them.

Printing tip: use your browser's Print → "Save as PDF"; tables fit on one landscape page.

It depends on concentration. At 1,000 mcg/mL (e.g. 2 mg in 2 mL) 100 mcg is 10 units; at 2,500 mcg/mL it is 4 units; at 5,000 mcg/mL it is 2 units.

On a U-100 syringe, 1 unit = 0.01 mL, so mcg per unit = concentration (mcg/mL) ÷ 100.

No. A syringe unit is a volume (0.01 mL on U-100). How many mcg it holds depends on how concentrated the solution is.

Last updated: 2026-10-02 · Found an error? Report it.