Simple vs Compound Interest " Full Comparison (2026)
When you put money in a bank or take a loan, the type of interest being used determines how much you earn or owe. Simple interest and compound interest may seem similar initially, but over time the difference is enormous. This guide gives you a complete, no-jargon comparison so you can make smarter financial decisions.
Compound Interest: A = P — (1 + r/n)^(n—t) | CI = A P
→ Calculate CI vs SI with our Free Calculator
What is Simple Interest?
Simple interest is calculated only on the original principal, regardless of how much interest has already accumulated. It grows in a straight line (linear growth). Common uses: some short-term personal loans, bonds.
What is Compound Interest?
Compound interest is calculated on principal + accumulated interest. Each period's interest becomes part of the principal for the next period. Result: exponential growth. Common uses: savings accounts, FDs, mutual funds, home loans.
Quick Comparison Table
| Factor | Simple Interest | Compound Interest |
|---|---|---|
| Calculated On | Principal only | Principal + Interest |
| Growth Type | Linear | Exponential |
| Formula | SI = PRT/100 | A = P(1+r/n)^nt |
| Good for investor? | Lower returns | ✅ Higher returns |
| Good for borrower? | ✅ Lower cost | Higher cost |
| Used In India | Short-term loans | FD, home loans, SIP |
Side-by-Side Numerical Example
1,00,000 invested at 10% for 10 years:
Simple Interest: SI = 1,00,000 — 10 — 10 / 100 = 1,00,000 interest. Total = 2,00,000
Compound Interest (annual): A = 1,00,000 — (1.10)^10 = 1,00,000 — 2.5937 = 2,59,374. CI = 1,59,374 interest. Total = 2,59,374
s Compound interest earns 59,374 MORE over just 10 years " with no extra effort!
When to Prefer Each
- ✅ As a borrower, prefer simple interest loans (lower total cost)
- ✅ As an investor, prefer compound interest savings (higher returns)
- ✅ Start investing early " time is the biggest factor in compounding
- Avoid high-interest compound debt (credit cards) " it works against you fast
Use Our Free Calculators
Compare SI vs CI Instantly " Free!
Use our compound interest calculator to project your investment growth and compare with simple interest.
Open Compound Interest Calculator →Also use our FD Calculator to calculate exactly how much your Fixed Deposit will earn with compound interest.
FAQs
Which is better for a savings account " SI or CI?
Compound interest is always better for savings. The more frequently interest compounds (daily > monthly > quarterly), the more you earn.
Do credit cards use simple or compound interest?
Credit cards use compound interest on unpaid balances " often compounded daily. This makes credit card debt extremely expensive if not paid in full each month.