Monthly Deposit Savings Calculator
Calculate your savings growth with regular monthly deposits and compare different compounding frequencies
This calculator helps users determine how long it will take to reach a savings goal with regular monthly deposits, while comparing different compounding frequencies (monthly, quarterly, semi-annually, or annually).
1. Key Features
✅ Inputs:
Initial deposit
Monthly deposit amount
Annual interest rate (%)
Target savings goal
Compounding frequency options (monthly, quarterly, semi-annually, annually)
✅ Outputs:
Time required (in years & months) to reach the goal
Total contributions (sum of all deposits)
Total interest earned
Comparison table showing how different compounding frequencies affect growth
2. How It Works (Formula)
The future value of a savings plan with regular deposits + compounding interest is calculated using:
Future Value Formula
Where:
= Future Value (target amount)
= Initial deposit
= Monthly deposit
= Annual interest rate (decimal)
= Compounding periods per year
= Time in years
Since we solve for , logarithmic methods or iterative calculations are used.
3. Compounding Comparison
The calculator compares how different compounding frequencies impact growth:
| Compounding | Periods/Year (n) | Impact on Growth |
|---|---|---|
| Annually | 1 | Slowest growth |
| Semi-Annually | 2 | Moderate growth |
| Quarterly | 4 | Faster growth |
| Monthly | 12 | Fastest growth |
Example:
$10,000 goal, $200/month, 5% interest:
Monthly compounding: Reached in ~7.1 years
Annual compounding: Reached in ~7.4 years
4. Example Calculation
Scenario:
Initial deposit = $1,000
Monthly deposit = $150
Annual interest rate = 6%
Target amount = $25,000
| Compounding | Time Required | Total Deposits | Interest Earned |
|---|---|---|---|
| Monthly (n=12) | 10.2 years | $19,360 | $5,640 |
| Quarterly (n=4) | 10.4 years | $19,720 | $5,280 |
| Annually (n=1) | 10.7 years | $20,260 | $4,740 |
Conclusion: More frequent compounding reduces time needed and increases interest earned.
5. Benefits of This Calculator
✔ Visual Comparison – See how compounding frequency affects growth.
✔ Better Financial Decisions – Choose accounts with higher compounding rates.
✔ Adjustable Inputs – Test different deposit amounts & interest rates.
✔ Goal Tracking – Know exactly when you’ll reach your target.
6. Applications
Retirement planning (401k, IRA growth)
Emergency fund building
Saving for a house/car down payment
Education fund (529 plans)