Money Multiplier=Reserve Ratio1​

Given a reserve ratio of 10% (or 0.10):

$\text{Money Multiplier} = \frac{1}{0.10} = 10$

If the Fed purchases a $1,000 government bond and you deposit the entire amount in your bank, the total potential change in the money supply is:

$\text{Total Potential Change} = \text{Initial Deposit} \times \text{Money Multiplier}$

$\text{Total Potential Change} = \$1,000 \times 10 = \$10,000$