Savings Interest Calculator

See how much interest you'll earn on your savings over time with compound interest.

Calculator

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
Future Value = $47,598
4

Calculate Total Interest

  • Total Deposits = $10,000 + ($200 × 120) = $34,000
  • Total Interest = $47,598 - $34,000
Total Interest = $13,598

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.