Interest Calculator

Interest
₱19,101.60
balance ends at ₱119,101.60
Final balance₱119,101.60
If simple₱18,000.00
Effective annual rate6.00%
[ CALCULATION ]
Principal₱100,000.00
Rate a year6.00
Term years3
Compounds once a year1
Effective annual rate what the rate costs over a year once it compounds6.00
Balance at the end ₱100,000.00 × (1 + 6.00% ÷ 1)^3₱119,101.60
Interest ₱119,101.60 − ₱100,000.00₱19,101.60
If it were simple interest ₱1,101.60 less₱18,000.00
[ WHAT THIS IS ]

Interest on a lump sum that sits untouched. Simple interest is charged on the original amount and grows in a straight line; compound interest is charged on the balance, which already includes what has been added, so it accelerates.

Both figures are always computed, whichever you pick, because the gap between them is usually what you are trying to see. And the rate carries its own period — per year or per month — because a monthly rate read as an annual one is off by a factor of twelve.

[ QUESTIONS ]

The lender quoted me 3% — is that a year or a month?

Ask, because the difference is enormous. Philippine lending is very often quoted per month, and 3% a month is 36% a year before compounding and 42.58% after. Reading a monthly rate as an annual one understates what you will pay by roughly twelve times, which is why the period is a field here rather than an assumption.

What is the difference between simple and compound interest?

Simple interest is charged on the original amount only, so it grows in a straight line. Compound interest is charged on the balance, which already includes the interest added so far, so it accelerates. Over one compounding period they are identical; over any longer term compound is always more. Both figures are shown here whichever you choose.

What is the effective annual rate?

What a nominal rate actually costs over a year once compounding is counted. 6% compounded monthly is 6.17% effective, because each month you begin paying interest on the previous month’s interest. It is the figure to compare two offers on — nominal rates with different compounding frequencies are not comparable.

Is this the same as a loan calculator?

No. This grows a lump sum that sits untouched. A loan is amortised — you make regular payments against a shrinking balance, so the interest falls each period. Use the Loan Calculator for anything with a monthly payment.

Can I enter part of a year?

Yes. Type 0.5 for six months, or 2.25 for two years and three months. Simple interest scales exactly; compound interest applies the formula across the fraction of a period.

[ THE MATHS ]
Simple
I = P × r × t
Compound
A = P (1 + r/n)nt
[ WORKED ]
₱100,000 at 6% for 3 years
Simple — 100,000 × 6% × 3 ₱18,000.00
Compound, once a year ₱19,101.60

₱1,101.60 apart over three years. Over thirty the same rate would put them ₱270,000 apart.

[ A MONTHLY RATE IS NOT ANNUAL ]
3% read as a year 3.00%
3% a month, nominal 36.00%
3% a month, compounded 42.58%

On ₱100,000 over a year that is ₱3,000 against ₱42,576. Always ask which period a quoted rate is for.

[ NEXT ]
21Loan CalculatorAmortised payments against a shrinking balance
24Savings CalculatorRegular deposits compounding over time
32Percentage CalculatorThe percentage arithmetic underneath
[ IMPORTANT ]

An actual quotation includes fees, insurance and documentary stamp tax, so an offer letter will normally differ from a figure computed here. Nothing you type here is sent to our servers — the calculation runs entirely in your browser.