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peptide syringe calculator

10 mg in 3 mL = 3.3333 mg/mL, so 250 mcg is 0.075 mL = 7.5 units on a U-100 syringe.

The same draw reads differently on each barrel. Choose the syringe you have and the calculator shows the exact line, the nearest printed mark and how much that mark delivers.

mL
syringe
price, vial size and certificate correction
USD
mL

Most 2–15 mg vials hold 3 mL.

mg

From the lot certificate; it replaces the label amount.

%

draw 7.5 units

0.075 mL on a 0.3 mL U-100 syringe

concentration
3.3333 mg/mL
per unit
33.333 mcg per unit
full draws per vial
40
cost per draw
—
051015202530
exactly on the 7.5 mark · 0.075 mL
the working
  1. 10 mg ÷ 3 mL = 3.3333 mg/mL
  2. 250 mcg ÷ 3.3333 mg/mL = 0.075 mL
  3. 0.075 mL × 100 = 7.5 units on a 0.3 mL U-100 syringe
  4. 10 mg ÷ 250 mcg = 40 → 40 full draws

If this is a prescription, the dose and volume on your pharmacy label take priority. Ask your pharmacist about any mismatch.

updated Nov 4, 2026 · exact arithmetic, checked against 21 worked cases

barrels and marks

syringe guide

Syringe types, capacity and printed marks
syringeholdsprinted marks1 unit
0.3 mL insulin (U-100, 30 units)0.3 mL0.5 or 1 unit0.01 mL
0.5 mL insulin (U-100, 50 units)0.5 mL1 or 0.5 unit0.01 mL
1 mL insulin (U-100, 100 units)1 mL2 or 1 unit0.01 mL
0.5 mL U-40 (20 units)0.5 mL1 unit0.025 mL
1 mL U-40 (40 units)1 mL1 or 2 unit0.025 mL
1 mL tuberculin (0.01 mL marks)1 mL0.01 mL—
3 mL syringe (0.1 mL marks)3 mL0.1 or 0.05 mL—

the arithmetic

formulas

  • concentration = amount in the vial ÷ water added (mg/mL)
  • mL per draw = amount per draw ÷ concentration
  • syringe units = mL × 100 (U-100) or × 40 (U-40)
  • water to add = vial amount × units ÷ (amount per draw × 100)
  • cost per draw = vial price × amount per draw ÷ vial amount

Worked: 10 mg ÷ 2 mL = 5 mg/mL; 0.25 mg ÷ 5 = 0.05 mL; × 100 = 5 units.

what the numbers mean · where they come from

terms and sources

  • Label amount or measured amount. The calculator starts from the amount printed on the vial. A lot certificate’s measured content (net peptide content, in mg) can replace it for the vial that was tested. HPLC purity is a share of peak area, not a mass, so a purity-only correction is shown as an estimate. See HPLC, certificate of analysis and how to read a peptide COA.
  • Concentration. Amount in the vial ÷ water added. Terms: reconstitution, bacteriostatic water, lyophilized.
  • Syringe units. A volume: 0.01 mL per unit on a U-100 syringe, 0.025 mL on U-40. Units say nothing about the compound until the concentration is known.
  • Cost per draw. Vial price × amount per draw ÷ vial amount, from the price per mg of a current offer. Price history: peptide price tracker.

Arithmetic only, on the numbers entered. Amounts from labels or trials are cited references, not recommendations; PeptideTech does not give personal use instructions and does not test products.

short answers

calculator questions

What do the lines on an insulin syringe mean?
Each line is a volume in units: 0.01 mL per unit on U-100. 0.3 mL barrels usually mark every half unit, 0.5 mL every unit and 1 mL every 2 units, labelled every 5 or 10.
Can I use a U-40 syringe with a U-100 calculation?
No. U-40 marks are 2.5 times larger than U-100 marks, so a U-100 reading drawn on a U-40 syringe delivers 2.5 times the volume. Choose the scale printed on your syringe.
What is the smallest amount I can measure?
Below about 2 units the error of reading a line becomes a large share of the draw. Add more water so the same amount reads more units.

more calculators

related

Volume and concentration arithmetic for laboratory reconstitution; not medical advice. API: /api/calc. Syringe scales: 0.3 mL U-100, 0.5 mL U-100, 1 mL U-100, 0.5 mL U-40, 1 mL U-40, 1 mL syringe, 3 mL syringe.