How many units is 5 mg?
5 mg is 5,000 mcg. On a U-100 insulin syringe, 100 units are 1 mL,[1] so 5 mg fits only when the liquid is 5 mg/mL or stronger. At 10 mg/mL it is 5 ÷ 10 = 0.5 mL, or 50 units; at 20 mg/mL it is 25 units.
5 mg to units chart
| Strength | mL | Units (U-100) | Smallest syringe | Reading | One-unit misread |
|---|---|---|---|---|---|
| 2.5 mg/mL | 2 | 200 | – | Over 1 mL (2 mL): too large for an insulin syringe | – |
| 5 mg/mL | 1 | 100 | 1 mL | On a line of the 1 mL syringe | ±1% |
| 10 mg/mL | 0.5 | 50 | 0.5 mL | On a line of the 0.5 mL syringe | ±2% |
| 15 mg/mL | 0.333 | 33.33 | 0.5 mL | Between the 33 and 34 lines (1-unit marks) | ±3% |
| 20 mg/mL | 0.25 | 25 | 0.3 mL | On a line of the 0.3 mL syringe | ±4% |
| 25 mg/mL | 0.2 | 20 | 0.3 mL | On a line of the 0.3 mL syringe | ±5% |
| 50 mg/mL | 0.1 | 10 | 0.3 mL | On a line of the 0.3 mL syringe | ±10% |
The first row shows what happens below 5 mg/mL: the volume passes 1 mL. From 15 mg/mL it fits a 0.5 mL syringe, and from 20 mg/mL a 0.3 mL one.
The 1 mL ceiling
The largest common U-100 insulin syringe holds 100 units, which is 1 mL.[2] At 5 mg/mL the dose fills it exactly (100 units). At 2.5 mg/mL it would be 2 mL, twice what the syringe holds. Volumes like that are measured on syringes marked in mL, which come in 1 mL and larger sizes.[3]
units = 5 mg ÷ strength (mg/mL) × 100 = 500 ÷ strength
Stronger liquid, smaller volume, bigger stakes
At 50 mg/mL, 5 mg is just 10 units. Each unit then holds 0.5 mg, so one unit off is 10% of the dose. At 10 mg/mL each unit holds 0.1 mg and one unit off is 2%. The units to mg calculator shows how much each unit holds at any strength, and mg to mL handles volumes above 1 mL.
7.5 mg to units and 10 mg to units
7.5 mg is 75 units at 10 mg/mL and 30 units at 25 mg/mL; 10 mg is 100 units (the full 1 mL) at 10 mg/mL and 50 units at 20 mg/mL. Below 7.5 mg/mL a 7.5 mg dose, and below 10 mg/mL a 10 mg dose, no longer fit a 1 mL insulin syringe.
| Strength | 7.5 mg (units) | 10 mg (units) |
|---|---|---|
| 5 mg/mL | – (1.5 mL) | – (2 mL) |
| 10 mg/mL | 75 | 100 |
| 15 mg/mL | 50 | 66.67 |
| 20 mg/mL | 37.5 | 50 |
| 25 mg/mL | 30 | 40 |
| 50 mg/mL | 15 | 20 |
Half this dose is charted in 2.5 mg to units; the barrels that hold it are compared in insulin syringe sizes.
Frequently asked questions
How many units is 5 mg at 25 mg/mL?
20 units, or 0.2 mL.
What is the weakest strength that fits 5 mg in a 1 mL syringe?
5 mg/mL. At that strength 5 mg is exactly 1 mL, or 100 units.
How many mL is 5 mg at 50 mg/mL?
0.1 mL, which is 10 units on a U-100 syringe.