Savings Interest Calculator
See how much interest you'll earn on your savings over time with compound interest.
Result
- Total Deposits
- $0.00
- Future Value
- $0.00
- Total Interest Earned
- $0.00
- Interest as % of Deposits
- 0.0%
Formula & Guide
Formula
I
Total Interest
Interest = FV - Total Deposits
Future Value minus all deposits
FV
Future Value
FV = P(1+r)^n + PMT×[(1+r)^n-1]/r
Combined lump sum and annuity
Formula Variables
FV
Future Value
Total value at end of period
P
Principal
Initial deposit
PMT
Payment
Regular deposit
r
Rate
Interest rate per period
n
Periods
Number of compounding periods
Step-by-Step Scenario
Example Scenario
Initial Principal
$10,000
Monthly Deposit
$200
Interest Rate
5% annually
Time Period
10 years
1
Calculate Future Value of Principal
- FV_principal = $10,000 × (1 + 0.05/12)^(12×10)
- FV_principal = $10,000 × (1.004167)^120
- FV_principal ≈ $16,470
2
Calculate Future Value of Monthly Deposits
- Monthly rate = 5% / 12 = 0.4167%
- FV_deposits = $200 × [(1.004167)^120 - 1] / 0.004167
- FV_deposits ≈ $31,128
3
Calculate Total Future Value
- Future Value = $16,470 + $31,128
4
Calculate Total Interest
- Total Deposits = $10,000 + ($200 × 120) = $34,000
- Total Interest = $47,598 - $34,000
Additional Examples
High-Yield Savings
Principal: $20,000
Rate: 4.5%
Time: 5 years
Interest Earned
$4,876
Long-Term Investment
Monthly: $500
Rate: 8%
Time: 30 years
Interest Earned
$565,122
Characteristics of Total Interest
Compound Growth
Interest earns interest, creating exponential growth over time.
Time Multiplier
Longer periods dramatically increase total interest earned.
Regular Deposits
Consistent contributions build a larger base for compounding.
Rate Matters
Even small rate differences compound into big differences over time.
Important Notes
- Higher rates often come with more risk.
- Inflation reduces the real value of interest earned.
- Tax on interest may apply; consider tax-advantaged accounts.
- Reinvesting interest is key to compounding.
Frequently Asked Questions
Common questions about savings interest.
Total Interest = Future Value - Total Deposits. The future value includes compounded interest on your initial deposit plus interest on regular contributions.
Yes! More frequent compounding means you earn interest on interest more often, increasing total returns. Daily compounding beats monthly, which beats annual.
High-yield savings accounts offer 4-5% APY. CDs may offer slightly higher rates. Long-term investments in diversified portfolios historically average 7-10%.