Peptide Calculator

Conversions

Converting mg, mcg, and Syringe Units

Peptide math involves three different scales: mass (mg and mcg), volume (mL), and syringe units. Mix them up and your dose can be off by a factor of 1,000. Here's every conversion you need in one place.

Updated June 8, 2026 · ~3 min read

Mass: milligrams and micrograms

1 mg = 1,000 mcg  ·  1 mcg = 0.001 mg

To go from mg to mcg, multiply by 1,000. To go from mcg to mg, divide by 1,000. Vials are usually labeled in mg; doses are often written in mcg, so this is the conversion you'll use most.

Micrograms (mcg)Milligrams (mg)
100 mcg0.1 mg
250 mcg0.25 mg
500 mcg0.5 mg
1,000 mcg1 mg

Volume to units

Mass doesn't convert directly to units. You first turn your dose into a volume (using the concentration), then turn the volume into units using your syringe's scale.

Units = volume (mL) × units per mL
U-100: × 100  ·  U-50: × 50  ·  U-40: × 40
VolumeU-100U-50U-40
0.05 mL52.52
0.10 mL1054
0.20 mL20108
0.50 mL502520

Putting it together

The full chain for any dose is:

dose (mg) ÷ concentration (mg/mL) = volume (mL)
volume (mL) × units-per-mL = syringe units

Example: a 250 mcg dose with a 2.5 mg/mL concentration on a U-100 syringe → 0.25 mg ÷ 2.5 = 0.1 mL → 0.1 × 100 = 10 units.

Skip the conversions

Enter your numbers in mg or mcg, pick your syringe, and the calculator handles every conversion for you.

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This guide is for calculation and educational purposes only and is not medical advice. It does not recommend any peptide, dose, or protocol. Always consult a qualified clinician before starting, changing, or stopping any peptide.