PeptideCalculations

Vial yield calculator

Divide the mass in the vial by the amount per draw. The water volume does not enter into it.

vial ÷ amount per draw

$
Full draws
—draws
exactly —, with — mcg left after the last full draw
Cost per draw
—
Cost per mg
—

Yield table

Vial100 mcg draws250 mcg draws500 mcg draws1 mg draws2.5 mg draws
1 mg104210
2 mg208420
3 mg3012631
5 mg50201052
10 mg1004020104
15 mg1506030156
20 mg2008040208
30 mg300120603012
50 mg5002001005020
60 mg6002401206024

Yield is a mass question, not a volume question

The number of draws in a vial depends on two masses: what is in the vial and what you want in each syringe. Water sets how large each draw is in millilitres and units, but it cannot create or remove peptide. A 10 mg vial holds 40 draws of 250 mcg whether you add 1 mL or 3 mL; with 1 mL each draw is 2.5 units, with 3 mL it is 7.5 units.

In practice the last draw is short. A little solution stays in the vial and in the syringe hub, so a vial that computes to 20 draws usually gives 19 full ones. The yield guide works through the rounding.

Questions

How many draws are in a 5 mg vial?

Divide 5,000 mcg by the amount per draw. At 250 mcg that is 20 draws; at 500 mcg, 10 draws; at 100 mcg, 50 draws. The water volume does not change the count.

Why does the water not change the number of draws?

Because the mass is fixed. More water spreads the same mass over more millilitres, so each draw is a larger volume, but the total mass and therefore the number of draws stays the same.

Why round down?

A vial that holds 12.5 draws gives you 12 full draws and a half-size remainder. The calculator shows the exact fraction and the leftover in mcg so you can see both.

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