Compare Savings Plans with Different Rates: $3,000 Example

To compare two savings plans with different interest rates, use the same $3,000 deposit and the same time period for both. First check whether each plan uses simple interest, APY, or compounded interest, because the math changes. Then compare the ending balance, not just the headline rate, and the winner is the plan that leaves you with more dollars after fees and rules are included.

What you need before you compare

Before you start, gather these details for both offers:

• The interest rate for each plan
• Whether each one uses simple interest, APY, or compounding
• The compounding frequency, if the interest is compounded
• Any monthly fee, minimum balance rule, or bonus condition
• The time period you want to compare, such as 1 year
• The starting deposit amount: $3,000

If one offer leaves out the compounding method or fee rules, you cannot compare it fairly until you find that information. A rate by itself does not tell you the full result.

How to compare the two plans

1. Put both plans on the same timeline.

Use the same deposit amount and the same time period for both plans. That is the only way the comparison stays fair.

For example, if you want to know which plan is better after 1 year, calculate both plans for 1 year. If you compare one plan after 1 year and the other after 3 years, the answer will be misleading because the longer time gives interest more time to grow.

A clean comparison uses:

• The same principal: $3,000
• The same time period: for example, 1 year
• The same end point: the balance at the end of that period

2. Check how each interest rate works.

Before you calculate anything, confirm whether each offer uses simple interest, APY, or compounded interest.

• Simple interest means interest is calculated only on the original $3,000.
• APY already reflects compounding over a year, so it is usually the easiest number to compare for a one-year period.
• Compounded interest depends on the compounding frequency, such as monthly, quarterly, or daily.

Write down the formula you will use before plugging in numbers. That keeps the math consistent and makes it easier to check your work.

3. Calculate the ending balance for each plan.

Use the formula that matches each plan, then calculate each ending balance on the same $3,000 deposit.

For simple interest:

Ending balance = Principal + (Principal × Rate × Time)

For APY over 1 year:

Ending balance = Principal × (1 + APY)

For compounded interest:

Ending balance = Principal × (1 + Rate ÷ number of compounding periods)^(number of compounding periods × years)

Here is a worked example using a 1-year comparison and $3,000 deposited in each plan.

Plan A: 4.00% simple interest

Use the simple interest formula:

Ending balance = 3000 + (3000 × 0.04 × 1)

Ending balance = 3000 + 120

Ending balance = 3120

So Plan A ends with $3,120.00 after 1 year.

Plan B: 3.90% APY

Use the APY formula for 1 year:

Ending balance = 3000 × (1 + 0.039)

Ending balance = 3000 × 1.039

Ending balance = 3117

So Plan B ends with $3,117.00 after 1 year.

If one of your offers compounds monthly, quarterly, or daily instead of using APY, use its compounding formula and the stated frequency. The frequency changes the result, even when the headline rate looks close.

4. Compare the final dollar amount, not just the rate.

Now subtract the original $3,000 from each ending balance so you can compare the actual interest earned.

For Plan A:

3120 - 3000 = 120

Plan A earned $120.00.

For Plan B:

3117 - 3000 = 117

Plan B earned $117.00.

This is the comparison that matters. The plan with the higher rate on paper is not automatically the winner. The winner is the plan that leaves you with the larger ending balance and the larger dollar gain after the same time period.

5. Check for fees and rules that can change the result.

Before you pick the winner, check whether fees or account rules cut into the gain.

Look for:

• Monthly maintenance fees
• Minimum balance requirements
• Withdrawal limits or penalties
• Bonus interest that only applies if you meet conditions
• Promotional rates that expire after a short period

These details can change the result enough to flip the winner. For example, a plan that earns $120 in interest but charges a $5 monthly fee leaves you with less than a plan that earns $117 and has no fee.

If a fee applies, subtract it from the ending balance after interest is added. If the fee is charged monthly, include all months in the same time period you used for the comparison.

Which plan wins in the $3,000 example

Using the 1-year example above, Plan A is better because it ends at $3,120.00, while Plan B ends at $3,117.00. That means Plan A earns $120.00 and Plan B earns $117.00.

If your real offers use different rates, compounding schedules, or fees, repeat the same process with those exact terms. The winner is always the plan with the higher final dollar amount after the same deposit and the same time period.

Conclusion

For this $3,000, 1-year example, Plan A wins because it leaves you with the higher ending balance: $3,120.00 versus $3,117.00. If your actual offers have different compounding rules, fees, or minimum balance requirements, use those exact terms before deciding.