Compound Interest Calculator
Project your savings or investment growth with regular contributions and any compounding frequency
Quick answer
Compound Interest Calculator
P = starting principal, r = annual rate (decimal), n = compounding periods per year, t = years. Each regular contribution is added and then compounds for the remaining time, so the final balance includes interest on every deposit.
Formula
A = P(1 + r/n)^(nt) + contributions compounded each period
💰 Investment Details
📊 Your Results
💡 Of your final balance, ₹10,72,418 is interest — that is the power of compounding working on both your starting amount and every contribution.
📈 Growth Over Time
Year-by-year breakdown
| Year | Total Contributed | Interest Earned | Balance |
|---|---|---|---|
| 1 | ₹1,60,000 | ₹10,965 | ₹1,70,965 |
| 2 | ₹2,20,000 | ₹27,819 | ₹2,47,819 |
| 3 | ₹2,80,000 | ₹51,053 | ₹3,31,053 |
| 4 | ₹3,40,000 | ₹81,195 | ₹4,21,195 |
| 5 | ₹4,00,000 | ₹1,18,818 | ₹5,18,818 |
| 6 | ₹4,60,000 | ₹1,64,544 | ₹6,24,544 |
| 7 | ₹5,20,000 | ₹2,19,046 | ₹7,39,046 |
| 8 | ₹5,80,000 | ₹2,83,051 | ₹8,63,051 |
| 9 | ₹6,40,000 | ₹3,57,348 | ₹9,97,348 |
| 10 | ₹7,00,000 | ₹4,42,792 | ₹11,42,792 |
| 11 | ₹7,60,000 | ₹5,40,308 | ₹13,00,308 |
| 12 | ₹8,20,000 | ₹6,50,898 | ₹14,70,898 |
| 13 | ₹8,80,000 | ₹7,75,646 | ₹16,55,646 |
| 14 | ₹9,40,000 | ₹9,15,729 | ₹18,55,729 |
| 15 | ₹10,00,000 | ₹10,72,418 | ₹20,72,418 |
Worked example
Suppose you start with ₹100,000, add ₹5,000 every month, and earn 8% annual interest compounded monthly for 15 years. Your ₹100,000 alone would grow to about ₹330,000, but the monthly contributions add roughly ₹900,000 more in deposits-plus-growth. The result is a final balance well over ₹1.9M — of which more than half is interest you never deposited. That gap between what you put in and what you end with is compounding at work.
How compound interest works
With simple interest you earn a return only on your original principal. With compound interest each period’s interest is added to the balance, so the next period earns interest on a larger amount — interest on interest. The effect is small early on and accelerates over time, which is why starting early matters more than starting big. When you also contribute regularly, every deposit begins its own compounding journey, so consistent investing usually outperforms a single lump sum.
📈Formula
A = P(1 + r/n)^(nt) + contributions compounded each period💡How it works
P = starting principal, r = annual rate (decimal), n = compounding periods per year, t = years. Each regular contribution is added and then compounds for the remaining time, so the final balance includes interest on every deposit.
ℹ️ What is Compound Interest Calculator?
A compound interest calculator shows how money grows when interest is earned on both the principal and previously accumulated interest. It is the foundation of long-term investing, retirement planning, and understanding the true cost of debt.
📐 Formula
✏️ Worked Example
- 1r = 0.08, n = 12, t = 10
- 2A = 5000 × (1 + 0.08/12)^(12×10)
- 3A = 5000 × (1.006667)^120
- 4A = 5000 × 2.2196 ≈ $11,098
- 5Total interest = $11,098 − $5,000 = $6,098
💡 How to Interpret Results
- ▸More frequent compounding (daily > monthly > annually) yields slightly more, though the difference narrows at the same APR.
- ▸The Rule of 72: divide 72 by the annual rate to estimate years to double. At 8%: 9 years.
- ▸Compound interest works against you in debt: a credit card at 24% APR, paid minimums only, can balloon principal dramatically.
- ▸Starting 10 years earlier can more than double your final balance — time is the most important variable.
- ▸Always compare APY (not APR) across savings accounts — APY already reflects compounding frequency.
❓ Frequently Asked Questions
Related tools for this workflow
Continue the calculation
📚 Related Articles & Tips
Compound Interest Explained: The 8th Wonder of the World
Discover how compound interest can work for or against you in investments, loans, and savings.
Cap Rate vs Cash-on-Cash Return
Cap rate and cash-on-cash return answer different questions. Learn how to use both on a rental property deal.
Solar Panel Payback Period Explained
Work through solar payback with net cost, bill offset, incentives, net metering assumptions, and 25-year ROI.
How to Calculate Loan EMI (Complete Beginner Guide)
Learn how to calculate monthly loan payments (EMI) with simple formulas, real examples, and practical tips for loans.
Compound Interest FAQ
Get answers to common questions about compound interest calculator
Embed This Calculator
Add this calculator to your website for free
<iframe src="https://calcitools.com/calculators/compound-interest/embed" width="100%" height="600" frameborder="0" scrolling="auto" title="Compound Interest Calculator"></iframe>Why Embed?
- ✓ Free to use on your website
- ✓ Always up-to-date with latest features
- ✓ Mobile responsive design
- ✓ No maintenance required
- ✓ Fast loading and secure