APY Calculator

This APY calculator converts a stated nominal rate and compounding schedule into a practical yield view, then projects how the balance may grow over time.

That matters because a nominal rate on its own does not tell the full story. Compounding frequency changes the effective yield, and fees can reduce what you actually keep.

The calculator therefore shows both APY and effective net yield, along with the ending balance and the portion created by interest.

Enter the opening deposit, stated annual rate, and compounding frequency first.

Add a monthly contribution if you want to model a savings habit rather than a one-time deposit.

Use the fee field only when the account has a real annual drag so the net yield view stays realistic.

APY is derived from the nominal rate and compounding frequency using the standard annual percentage yield formula.

The growth projection converts the net annual rate into a monthly growth path so recurring deposits can be added over time.

Effective net yield compares total growth with total contributed capital after any annual fee drag is applied.

Two products can advertise similar nominal rates but still produce different APYs if one compounds daily and the other compounds monthly.

A small recurring contribution can matter more to the final balance than the difference between monthly and daily compounding over shorter periods.

APY is the most useful rate for comparing deposit products on a like-for-like basis. Effective net yield is more honest when a fee or spread drag is involved.

If balance growth is mostly coming from deposits rather than interest, the account is still useful, but the rate itself is not doing the heavy lifting.