APR, also known as annual percentage rate, is the amount earned by investors who lend their crypto tokens and is calculated using the initial investment and the interest rate. It is different from APY, another interest rate calculation, and is used to determine the interest earned from various investments or loans. The APR can vary and is determined by the amount of interest paid annually on the principal amount. It is expressed as a percentage and does not include any fees. The calculation for APR is based on simple interest and is used to compare different investment options. It is important to consider the APR when choosing a provider for staking crypto tokens.