Reconstitution Calculator
Reconstitution & Concentration Calculator
Enter vial contents, diluent volume and target amount. Get concentration, draw volume and the matching syringe marking.
Syringe reading
5units
U-100 · 1 mL syringe
Draw volume
0.05 mL
Concentration
5,000 mcg/mL
= 5 mg/mL
Draws per vial
40
at this amount, ignoring losses
Syringe (U-100)
For laboratory research use only. Not for human or veterinary use. This tool performs arithmetic unit conversions only; verify every result against your own procedures and measuring equipment.
How the calculation works
Reconstitution math is two steps: work out the concentration of the finished solution, then work out what volume contains your target amount.
Concentration (mcg/mL) = vial contents (mcg) ÷ diluent volume (mL)
Draw volume (mL) = target amount (mcg) ÷ concentration (mcg/mL)
Syringe units (U-100) = draw volume (mL) × 100
Worked example: a 10 mg vial is 10,000 mcg. With 2 mL of diluent the concentration is 5,000 mcg/mL. For a 250 mcg target, draw volume = 250 ÷ 5,000 = 0.05 mL, which is 5 units on a U-100 syringe.
Diluent volume reference chart
The same vial gives very different syringe readings depending on how much diluent is used. Values below are U-100 syringe units for common target amounts.
| Vial | Diluent | Concentration | 100 mcg | 250 mcg | 500 mcg |
|---|---|---|---|---|---|
| 2 mg | 1 mL | 2 mg/mL | 5 units | 12.5 units | 25 units |
| 5 mg | 1 mL | 5 mg/mL | 2 units | 5 units | 10 units |
| 5 mg | 2 mL | 2.5 mg/mL | 4 units | 10 units | 20 units |
| 10 mg | 1 mL | 10 mg/mL | 1 units | 2.5 units | 5 units |
| 10 mg | 2 mL | 5 mg/mL | 2 units | 5 units | 10 units |
| 10 mg | 5 mL | 2 mg/mL | 5 units | 12.5 units | 25 units |
| 30 mg | 3 mL | 10 mg/mL | 1 units | 2.5 units | 5 units |
All unit values assume U-100 syringes (100 units per mL).
U-100 syringe unit reference
| Draw volume | Units on a U-100 syringe |
|---|---|
| 0.05 mL | 5 units |
| 0.10 mL | 10 units |
| 0.20 mL | 20 units |
| 0.25 mL | 25 units |
| 0.50 mL | 50 units |
| 1.00 mL | 100 units |
Four measurement mistakes to avoid
- Mixing up mg and mcg. 1 mg = 1,000 mcg. A 5 mg vial holds 5,000 mcg, and a 250 mcg target is 0.25 mg.
- Assuming the wrong syringe scale. U-100 and U-40 syringes are not interchangeable. Read the syringe barrel, then use the matching conversion.
- Changing diluent volume without recalculating. Every change in diluent volume changes the concentration. Record the exact volume used for each vial.
- Working at the limit of the scale. Very small draws carry a large relative error. Use the suggested diluent volume when the calculator flags a small draw.
Frequently asked questions
How is concentration calculated after reconstitution?
Concentration is the total mass in the vial divided by the total diluent volume. A 10 mg vial (10,000 mcg) reconstituted with 2 mL of diluent is 5,000 mcg/mL, or 5 mg/mL. Changing the diluent volume changes the concentration, and therefore the draw volume for any given target amount.
How do I convert a draw volume into syringe units?
On a U-100 syringe there are 100 units per 1 mL, so units = draw volume in mL × 100. A 0.05 mL draw is 5 units, 0.25 mL is 25 units, and 0.5 mL is 50 units. The calculator does this conversion for you and shows the level on the syringe graphic.
What is the difference between U-100 and U-40 syringes?
A U-100 syringe has 100 units per mL; a U-40 syringe has only 40 units per mL. Reading a U-100 result on a U-40 syringe, or the reverse, changes the volume by a factor of 2.5. This calculator is built for U-100 markings, so confirm the syringe type printed on the barrel before relying on any unit reading.
Why does the diluent volume I choose matter?
More diluent gives a lower concentration and a larger draw volume for the same target amount, which reduces the relative error from reading small markings. Less diluent gives a higher concentration and a smaller draw. The calculator warns you when a draw is small enough to be hard to measure precisely and suggests a diluent volume that brings it into a comfortable range.
How do I convert between mg and mcg?
1 mg equals 1,000 mcg. To go from mcg to mg divide by 1,000; to go from mg to mcg multiply by 1,000. When you switch the unit toggle on the calculator, the value you have entered is converted automatically so the quantity stays the same.
Does the volume of the dry powder change the result?
The calculator assumes the lyophilized cake adds negligible volume, which is standard practice for small vial sizes. If your work needs tighter accuracy, measure the final solution volume directly and enter that as the diluent volume.
Does this calculator store or send my inputs?
No. Every calculation runs in your browser. Inputs are only written to the page address if you choose to copy the link to a calculation, so you can bookmark or share the exact numbers.
Is this calculator for human or veterinary use?
No. Medtruva products and this tool are intended for laboratory research use only. The calculator performs arithmetic unit conversions and is not medical advice or a dosing tool.
For laboratory research use only. Not for human or veterinary use. Nothing on this page is medical advice.
