Savings & Interest
Savings Calculator
See how your savings grow over time with compound interest and regular contributions — adjust compounding frequency, contribution schedule, and term to model any scenario.
Contribution Frequency
Compounding Frequency
🔒 All calculations happen instantly in your browser. No data is sent to any server.
How the calculation works
The calculator compounds interest at the selected frequency and adds contributions proportionally across compounding periods:
Balance after each period = Previous Balance × (1 + r/n) + Contribution per period
Where r = annual rate, n = compounding periods per year. This repeats for every period across the full term.
Example: $5,000 initial · $200/mo · 4.5% rate · monthly compounding · 20 years
Final balance ≈ $120,000+ — contributions total ~$53,000, rest is interest
Frequently Asked Questions
- Compound interest earns interest on both principal and previously earned interest. With monthly compounding at 5%, your $10,000 earns $500 in year 1, then $525 in year 2 (on $10,500), and so on — accelerating exponentially over time.
- Daily compounding yields slightly more than monthly, which beats quarterly. On $10,000 at 5% over 10 years: annual compounding = $16,289; monthly = $16,471; daily = $16,487. The differences are real but modest at typical savings rates.
- Profoundly. $200/month from age 25 to 65 at 6% = ~$400,000. Starting at 35 = ~$200,000. Ten extra years of compounding roughly doubles the outcome. Starting early is the single most impactful savings decision.
- High-yield savings accounts (HYSA): 4–5% (2024). CDs: 4–5%. Bond index funds: 3–5% long-term. Stock index funds: 7–10% historical average (not guaranteed). Use conservative rates for planning — over-estimating returns is a common mistake.
- No — results are in nominal (not inflation-adjusted) dollars. To estimate real purchasing power, subtract the inflation rate from your nominal rate. At 5% return and 3% inflation, the real rate is approximately 2%.
- A quick way to estimate doubling time: divide 72 by the annual rate. At 6%, money doubles in 72 ÷ 6 = 12 years. At 4%, it takes 18 years. Use the calculator for precise figures; the rule of 72 is a mental math shortcut.