Dilution changes concentration, not the total amount
When a compatible liquid is added, the total labelled amount remains the same while it is distributed through a larger volume.
More liquid → lower concentration per mL
Less liquid → higher concentration per mL
Less liquid → higher concentration per mL
This means the liquid volume needed to contain the same amount will change. It does not mean the intended amount itself has changed.
A mathematical comparison
Example only:
10 mg in 1 mL equals 10 mg/mL. The same 10 mg in 2 mL equals 5 mg/mL.
Dilution is product-specific
Do not select a liquid or volume based only on convenience or a calculator. Compatibility, sterility, stability and the manufacturer's instructions all matter.