Calculadora de Ahorro — Fórmula

## How Savings Growth Is Calculated

This calculator uses the compound interest formula with regular contributions:

**FV = P(1+r)^n + PMT × [(1+r)^n - 1] / r**

Where P = initial deposit, PMT = monthly contribution, r = monthly rate, n = total months.

Ejemplo Resuelto

$5,000 initial deposit with $200/month at 4.5% APY for 10 years.

  1. Monthly rate = 4.5% / 12 = 0.375%
  2. Months = 10 × 12 = 120
  3. Initial deposit grows to: $5,000 × 1.00375^120 = $7,834
  4. Contributions grow to: $200 × (1.00375^120 - 1) / 0.00375 = $30,038
  5. Future value = $7,834 + $30,038 = $37,872
  6. Total contributed = $5,000 + $24,000 = $29,000
  7. Interest earned = $37,872 - $29,000 = $8,872