Savings Interest Calculator
Estimate savings interest earned over time with optional monthly deposits.
Savings growth
Track the projected balance against the amount you contribute over time.
How this calculator works
How to use this calculator
1. Enter your starting savings balance.
2. Enter the amount you plan to deposit each month.
3. Enter the annual interest rate.
4. Enter the number of years.
5. Click Calculate Savings Interest.
Formula used
The calculator applies monthly compounding and adds the monthly deposit after each month's interest is calculated.
Monthly rate = annual rate ÷ 12
Each month:
New balance = Current balance × (1 + monthly rate) + monthly deposit
Estimated interest = Future balance − total amount contributed
Example calculation
Example: $5,000 starting balance, $200 monthly deposit, 4% annual interest, 3 years
After 36 monthly periods:
Estimated future balance ≈ $13,272.67
Total contributed = $12,200
Estimated interest earned ≈ $1,072.67
What the result means
The future balance combines your starting amount, monthly deposits, and estimated interest. The interest figure is the portion of the final balance above your total contributions.
Frequently asked questions
When are monthly deposits added?
The calculator adds each monthly deposit after that month's interest is applied.
Does the calculator use monthly compounding?
Yes. The annual rate is divided by 12 and applied once per month.
Does this include taxes, account fees, or changing rates?
No. It assumes a constant rate and does not include taxes or fees.