เครื่องคำนวณดอกเบี้ยทบต้น

คำถามที่พบบ่อย

›What is compound interest?

Interest earned on both your original principal and previously earned interest. Each period the base grows, so the next period's interest grows too.

›Monthly vs annual compounding — does it matter?

Yes, but the difference is small at typical rates. Monthly compounding at 5% APR = ~5.12% effective annual yield.

›How is this different from APY?

APY = annual percentage yield, the effective rate after compounding. APR is the nominal rate before compounding. Both are useful when comparing accounts.

›Does it model taxes?

No — outputs are gross. Tax-advantaged accounts (Roth IRA, ISA) keep gains tax-free; taxable accounts pay annual tax.

›Is the calculator free?

Yes — free, no signup, runs in your browser.