Enter your vial, your water, and your target dose — the math researchers actually need, on the page.
How to use this calculator
Four picks, no math — the answer updates as you go.
Choose the syringe size you actually have: 0.3 mL, 0.5 mL or 1 mL. The scale in the answer matches it.
The milligrams printed on the vial label. Anything not listed goes in as a custom size.
How much bacteriostatic water you mixed into the vial, in mL.
Choose the dose in mcg or mg — the toggle converts for you.
"Draw to" tells you the exact mark on your syringe, shown in red on the scale.
Built for standard U-100 insulin syringes. Research use only.
Calculator questions
What does this calculator actually do?
It turns three things you know — your vial size, how much water you added, and the dose you want — into the one thing you need at the syringe: the exact unit mark to draw to.
Does it cost anything or need an account?
No. It is free, on this page, with no sign-up. Your numbers never leave your browser.
Why does the syringe size matter?
A unit is a hundredth of a millilitre, so a 0.5 mL syringe tops out at 50 units while a 1 mL syringe goes to 100. Picking your real syringe makes the scale — and the red fill — match what is in your hand.
How long does a mixed vial keep?
Once it is mixed with bacteriostatic water, keep it refrigerated at 2°C – 8°C and use it within 45 days.