The HGH Concentration Formula
The single formula behind every reconstitution calculator, how to rearrange it, and how to check your result.
Last updated November 11, 2026
The formula
Everything else is a rearrangement of this relationship.
| You know | You want | Formula |
|---|---|---|
| Amount and volume | Concentration | C = A ÷ V |
| Amount and concentration | Volume | V = A ÷ C |
| Concentration and volume | Amount | A = C × V |
Keep units consistent
The formula works only when the units agree. Convert mass to mg and volume to mL first, then divide. The result is in mg/mL. If your amount is in IU, the result is in IU/mL, and it stays in IU/mL unless an official, product-specific factor is available.
Worked example 1: mg and mL
10 mg in 2 mL: C = 10 ÷ 2 = 5 mg/mL.
Worked example 2: mixed units
2,500 mcg in 5,000 µL. Convert to 2.5 mg and 5 mL. C = 2.5 ÷ 5 = 0.5 mg/mL.
Worked example 3: rearranged
To hold 20 mg at 5 mg/mL: V = 20 ÷ 5 = 4 mL. These are generic numbers for practice and not a recommended mixture.
How volume changes concentration
Concentration and volume move in opposite directions when the amount stays fixed. Double the liquid and the concentration is halved. Halve the liquid and it doubles.
Checking your work
- Re-read each unit.
- Multiply C × V and compare with A.
- Ask whether the result is the right order of magnitude. A value a thousand times too big or small often points to an mg/mcg or mL/µL slip.