Tools

Milligrams in. Clicks out.

Enter what's in the vial and how much bacteriostatic water you added. You get the concentration, and what one click on the dial actually delivers. Add an amount per dispense and you get the clicks to dial for it.

It's arithmetic, and that's all it is. The pen dispenses whatever you put into the cartridge, at the amount you dial, and this page has no more opinion about what that is than the pen does.

Your numbers
mg
mL
mg

Concentration

— mg/mL

One click delivers

— mg

A full turn of the dial

— mg

Volume per dispense

— mL

Clicks to dial

—

Dispenses per vial

—

    How the math works

    Reconstitution is division. The powder in the vial doesn't change when you add water — you're spreading a fixed amount of material through a known volume, and the concentration is what falls out of that: amount divided by volume.

    The pen works in volume, not amount. The dial moves the plunger in fixed 0.01 mL steps, one click at a time, and one click is one unit on a standard 100-unit insulin syringe. The pen has no way to know what's dissolved in there. Concentration is the only thing that turns your amount into a number of clicks.

    So the water is the lever. Less water means a higher concentration and fewer clicks per dispense. More water means more clicks for the same material. Neither one is more accurate — you're choosing how finely the dial divides what you already have.

    What the dial can and can't do

    The number you got What it means
    Under 1 click Below the smallest step the pen makes. 0.01 mL is the floor and the dial can't split a click. Add more water — the same powder through a larger volume spreads each dispense across more clicks.
    A fraction of a click The dial stops on whole clicks only. Round to the nearest one and accept the difference, or change the water so the number lands whole. The calculator tells you which volume does that.
    Over 60 clicks Past the ceiling. 60 clicks is one full turn, and that's the most the dial holds at once, so it takes more than one press. Less water pulls the same amount into fewer clicks.
    Over 3 mL of water More than a cartridge holds. Split it across two cartridges, or use less water and a higher concentration.

    Where to go next

    Still stuck?

    Email tfortech@modtechsupply.net. A real person answers within one business day, and that person is the owner.

    MODTECH products are precision hardware sold for laboratory and research use only. They are not medical devices. No substances are included with or sold alongside any product, and nothing on this page constitutes medical advice or instructions for administering any substance to humans or animals.

    This calculator divides the numbers you enter and makes no recommendation about them.