Hong Life CalculatorsUnderstanding the maturity value calculator — concept and principle
Maturity value is what you receive at the end of an investment or loan term: the principal plus all interest. This calculator handles both simple interest, common for promissory notes and short deposits, and compound interest, and shows the difference between them.
How it is calculated
- Term in years t = days ÷ days in the year (365 or 360).
- Simple interest: MV = P × (1 + r × t).
- Compound interest: MV = P × (1 + r ÷ m)^(m × t), with m compounding periods a year.
- Interest earned = MV − P.
The principle
With simple interest, interest is calculated only on the original principal, so it grows in a straight line with time. With compound interest, interest is added to the balance at each period and itself earns interest, so growth curves upward. For terms under a year the two are very close; over many years compounding pulls ahead. A 360-day year, used for many money-market instruments, makes each day worth slightly more interest than a 365-day year.
Worked example
Default inputs: principal 10,000 USD, 4.5% a year, 180 days, 365-day year, simple interest, monthly compounding for comparison.
- t = 180 ÷ 365 ≈ 0.493 years.
- Simple MV = 10,000 × (1 + 0.045 × 0.493) ≈ 10,221.92 USD; interest 221.92 USD.
- Compound MV = 10,000 × (1 + 0.045 ÷ 12)^(12 × 0.493) ≈ 10,223.97 USD.
- Compound minus simple ≈ 2.06 USD.
- Because simple interest is selected, the maturity value shown is 10,221.92 USD.
| Principal (amount invested or lent) | Maturity value |
|---|---|
| 2,500 | $2,555.48 |
| 5,000 | $5,110.96 |
| 7,500 | $7,666.44 |
| 10,000 | $10,221.92 |
| 12,500 | $12,777.40 |
| 15,000 | $15,332.88 |
| 20,000 | $20,443.84 |
How to read the result
Use the interest type your contract states. Certificates of deposit and savings accounts usually compound; notes and many short-term deposits use simple interest. The small difference here shows that for a few months the choice barely matters, but for multi-year terms it does.
Common mistakes
- Entering the term in months or years instead of days.
- Using a 365-day year when the contract specifies 360 (or the other way round).
- Forgetting that taxes on interest reduce what you actually keep.
- Ignoring early-withdrawal penalties.
Frequently asked questions
What is the maturity value of a note?
The face value (principal) plus the interest due at the end of the term.
Why does a 360-day year give more interest?
The annual rate is divided over fewer days, so each day earns a bit more.
Is APY the same as maturity value?
No. APY is an annual rate including compounding; maturity value is the final amount in money.
Sources: Brigham & Houston, Fundamentals of Financial Management (time value of money) · FDIC, Truth in Savings (Regulation DD) consumer information