Maturity Amount
$ {{ format(maturityAmount) }}
After tax & inflation: $ {{ format(realMaturityAmount) }}
$ {{ format(principal) }} Principal $ {{ format(netInterestEarned) }} Interest (net)
$
% / yr
yrs mos
%
%
YearInterest ($)Ending ($)
{{ r.year }} {{ format(r.interestCum) }} {{ format(r.ending) }}
MonthInterest ($)Ending ($)
{{ r.period }} {{ format(r.interestCum) }} {{ format(r.ending) }}
Categories: Calculator , Finance
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Fixed-term deposits lock a lump sum for an agreed tenure and pay interest at a stated nominal rate. Because earnings compound at set intervals, the final balance grows faster than simple interest. Depositors value these products for predictable, low-risk returns and bank-level capital protection.

This calculator lets you enter principal, annual rate, tenure, and compounding frequency, then applies compound-interest mathematics, subtracts withholding tax, and discounts the result for inflation. A reactive engine instantly updates tables and an interactive charting layer to reveal growth trends and balances.

A traveller planning a three-year sabbatical, for example, can model how quarterly compounding compares with annual-payout offers before choosing a bank. Interest rules differ across jurisdictions; confirm local tax treatments before investing.

Technical Details:

Compound interest multiplies earnings because accrued interest is periodically added to the principal and itself earns interest. The effective yield therefore depends on nominal rate r, compounding frequency n, and time t. Adding tax reduces the interest portion, while discounting by inflation converts the maturity value to present-day purchasing power.

M=P⁢1+rnn⁢t
M – maturity value; P – principal; r – annual nominal rate (decimal); n – compounding periods per year; t – years invested.
FrequencyPeriods / Year (n)Typical Context
Annually1Long-term bonds, certificates
Semi-annually2Savings bonds, high-yield deposits
Quarterly4Retail fixed deposits
Monthly12Money-market linked deposits

Higher n values raise the effective annual yield because interest accrues more often, though differences narrow as n approaches infinity.

  • Principal – lump-sum deposit (USD or local currency).
  • Interest rate – quoted annual nominal rate, percent.
  • Tenure – investment length as years + months.
  • Compounding – annual, semi-annual, quarterly, or monthly.
  • Tax rate – withholding on earned interest, percent.
  • Inflation rate – expected annual inflation, percent.

Example (P = 10 000, r = 4 %, n = 4, t = 3 yrs, tax = 10 %, inflation = 2 %):

M=10000⁢ 1+0.04412 =11274.29 1274.29×1−0.10=1146.86 11274.291+0.023 =10623.84
  • Tax applies only to interest, not principal.
  • Inflation remains constant over the tenure.
  • Interest is credited precisely at each period end.
  • Early withdrawal penalties are not modelled.
  • Zero interest yields equal principal maturity.
  • Inflation above nominal rate yields real losses.
  • Extremely short tenures may skip compounding events.
  • Negative rates or inflation are mathematically allowed but rarely practical.

Formulae follow classical time-value-of-money treatments in Brigham & Ehrhardt’s Financial Management and actuarial tables issued by ISO 56 000-1. Inflation adjustment mirrors Fisher’s real-rate relation.

This computation uses only client-side arithmetic; no entered data leaves your device.

Step-by-Step Guide:

Follow these steps to project your deposit’s future value.

  1. Enter Principal in your currency.
  2. Select the annual Interest rate and Compounding frequency.
  3. Add tenure in years and months; partial years are allowed.
  4. (Optional) Expand Advanced to apply tax and inflation percentages.
  5. Review the highlighted maturity figures and switch tabs for schedules or charts.
  6. Download CSV schedules before closing the page to keep a permanent record.

FAQ:

Is my data stored?

No, all calculations happen locally; refreshing clears inputs.

Why is net interest lower?

The calculator deducts withholding tax from gross interest to reflect take-home earnings.

How are leap years handled?

Months are counted individually; leap days have negligible effect on compound totals.

Can I model monthly deposits?

No; the tool assumes a single upfront principal. Use a recurring deposit planner for staged contributions.

What if inflation is zero?

The real maturity equals the nominal maturity; purchasing power remains unchanged.

Glossary:

Principal
Initial lump-sum deposit.
Nominal Rate
Stated annual interest percentage.
Compounding
Frequency of interest crediting.
Maturity
Balance at tenure end.
Real Value
Inflation-adjusted maturity amount.

No data is transmitted or stored server-side.