Now that you understand how compound interest works, it’s time to run the numbers.

A high-yield savings account allows your savings to earn interest over time. How much you earn depends on factors such as your starting balance, APY, contributions, and how long your money stays in the account.

For this module, we'll use a 3.1% APY as a hypothetical example. Remember, HYSA rates are generally variable and can change.

Imagine you deposit $4,000 into an HYSA with a 3.1% APY and make no additional deposits.

Estimated Yearly Interest

A simple way to understand the approximate annual earnings is:

Starting Balance × APY

$4,000 × 0.031 = $124

At a 3.1% APY, $4,000 would earn approximately $124 over one year if the balance remained unchanged.

Breaking It Down

Using the APY to estimate equivalent growth over shorter periods:

Estimated Monthly Interest at the Start:

$4,000 × [(1.031)^(1/12) − 1]

≈ $10.19

Estimated Daily Interest at the Start:

$4,000 × [(1.031)^(1/365) − 1]

≈ $0.33

These daily and monthly figures describe the approximate equivalent growth rate at the starting balance. Actual banks may calculate and compound interest differently, so always review an account's terms.

Now imagine you:

Start with: $4,000
Contribute: $100 every month
APY: 3.1%
Save for: 5 years

Over five years, you would personally contribute:

$4,000 + ($100 × 12 × 5)

= $10,000 contributed

Using our calculator's assumption of monthly contributions and a constant 3.1% APY:

Estimated Ending Balance: $11,133.56

Estimated Interest Earned: $1,133.56

That means more than $1,100 of the estimated ending balance came from interest rather than your deposits.

Of course, a real HYSA's APY may rise or fall during those five years, so this is an educational projection rather than a guaranteed return.

Now it's your turn.

Use the EverFaith™ HYSA Savings Calculator to create your own savings scenario