Peptide Unit Conversion Calculator — mg, mcg, mL, U-100, U-40 | PepComputer

How to Use This Calculator

Select the units you are converting from: Choose mg, mcg, mL, U-100 units, or U-40 units from the input selector.
Enter the value: Type the numeric quantity you want to convert.
For mL conversions, enter concentration: If converting between volume (mL) and mass (mg/mcg), enter the reconstitution concentration in mcg/mL so the calculator can bridge the two.
Select target units: Choose the unit you want to convert to. The result appears instantly.
Cross-reference with the table below: Use the reference table to double-check conversions and understand relative magnitudes across unit types.

Example Conversion

A researcher wants to draw 250 mcg from a vial reconstituted at 2,500 mcg/mL using a U-100 syringe.

Conversion	Formula	Result
mcg → mL	250 ÷ 2,500	0.10 mL
mL → U-100 units	0.10 × 100	10 units
mL → U-40 units	0.10 × 40	4 units

Full Reference Conversion Table

Conversions between mass, volume, and syringe units at a concentration of 2,500 mcg/mL (5 mg vial + 2 mL BAC water — the most common reconstitution):

mcg	mg	mL	U-100 units	U-40 units
100	0.1	0.040	4	1.6
250	0.25	0.100	10	4
500	0.5	0.200	20	8
1,000	1	0.400	40	16
2,500	2.5	1.000	100	40

Assumes concentration of 2,500 mcg/mL. Results scale linearly — halve the concentration to double the volume.

U-100 vs U-40 Quick Reference

Syringe Type	Units per mL	mL per unit	Common volumes
U-100	100	0.01 mL	0.3 mL, 0.5 mL, 1 mL
U-40	40	0.025 mL	0.5 mL, 1 mL

Frequently asked questions

How do I convert mg to mcg?+

1 mg = 1,000 mcg. To convert mg to mcg, multiply by 1,000. To convert mcg to mg, divide by 1,000. Peptide vials are typically labelled in mg, while research protocol doses are expressed in mcg.

What is the difference between a U-100 and a U-40 syringe?+

U-100 syringes hold 100 insulin units per mL; U-40 syringes hold 40 units per mL. A U-100 syringe is far more common today. If you draw 10 units in a U-100 syringe, that is 0.10 mL. The same 0.10 mL drawn in a U-40 syringe reads as 4 units — a critical difference that causes dosing errors if syringes are mixed up.

How do I convert mL to U-100 units?+

Units = mL × 100. For example, 0.25 mL = 25 units on a U-100 syringe. Conversely, to convert U-100 units to mL, divide by 100: 40 units = 0.40 mL.

How do I convert mL to U-40 units?+

Units = mL × 40. For example, 0.25 mL = 10 units on a U-40 syringe. Conversely, to convert U-40 units to mL, divide by 40.

Why do peptide doses use mcg and not mg?+

Peptides are biologically active at very small quantities. Expressing doses in micrograms avoids decimal confusion — writing 250 mcg is clearer and less error-prone than writing 0.25 mg, especially when preparing injections at the bench.

How many mcg are in 1 mL of a reconstituted peptide?+

This depends entirely on reconstitution concentration. If you add 2 mL BAC water to a 5 mg vial, the concentration is 2,500 mcg/mL — so 1 mL contains 2,500 mcg. The concentration must always be known before converting mL to mcg.