How this calculation works
A deposit ladder spreads funds across several maturity dates. Total interest alone does not show when each principal amount returns, so this page displays a sorted dated maturity schedule as well as aggregate proceeds. The calculation deliberately uses an entered simple-interest convention. It does not claim to reproduce a particular bank’s cumulative fixed-deposit or recurring-deposit product.
Interest per tranche = principal × simple annual rate × tenor days/365; maturity = start + tenor daysA worked example
Two deposits start on 1 January 2026 with principal one thousand and simple annual rate ten percent. The 365-day tranche earns one hundred and matures on 1 January 2027. The thirty-day tranche earns about 8.21918 and matures on 31 January 2026. Total modeled interest is about 108.21918, although the proceeds arrive at those different dates.
Good to know
Bank-specific compounding, payout timing, tax withholding, early closure penalties and automatic rollover are excluded. An entered nominal bank rate should not be assumed to use this simple Actual/365 convention. This page does not recommend a bank, rate or maturity mix. Confirm the actual deposit terms before comparing the model with a statement or expected payout.
Reference: BCcampus — simple interest and time (opens in a new tab) ↗
What this calculation answers
A deposit ladder spreads funds across several maturity dates. Total interest alone does not show when each principal amount returns, so this page displays a sorted dated maturity schedule as well as aggregate proceeds.
The calculation deliberately uses an entered simple-interest convention. It does not claim to reproduce a particular bank’s cumulative fixed-deposit or recurring-deposit product.
The Cumulative fixed deposit and CD calculator compounds a cumulative deposit. This maturity ladder deliberately uses simple Actual/365 tranche interest and makes no bank-specific compounding claim.
Use the right input conventions
Each tranche has a start date, principal, simple annual percentage and whole-day tenor. Interest uses Actual/365, while maturity is start plus the entered calendar-day count in a date-only UTC calculation.
Dates must be actual calendar dates between 1900 and 2400, and maturity must remain in that range. No weekend or holiday adjustment is made, even when a maturity falls on a nonworking day.
Interpret the result
The schedule sorts by unadjusted maturity date rather than by the order in which tranches were entered. Principal and interest remain separately visible so cash returning from an old deposit is not confused with new earnings.
No reinvestment after maturity is assumed. Adding all maturity proceeds therefore describes amounts returned at different dates, not a single future-value balance or an annualized portfolio return.
Work through the example
Two deposits start on 1 January 2026 with principal one thousand and simple annual rate ten percent. The 365-day tranche earns one hundred and matures on 1 January 2027.
The thirty-day tranche earns about 8.21918 and matures on 31 January 2026. Total modeled interest is about 108.21918, although the proceeds arrive at those different dates.
Where the model stops
Bank-specific compounding, payout timing, tax withholding, early closure penalties and automatic rollover are excluded. An entered nominal bank rate should not be assumed to use this simple Actual/365 convention.
This page does not recommend a bank, rate or maturity mix. Confirm the actual deposit terms before comparing the model with a statement or expected payout.
A few questions, answered
Is this the same as quarterly compounded cumulative FD interest?
No. This page explicitly uses simple Actual/365 interest for each entered tranche.
What changes in the comparison?
Lengthen the short tranche and inspect both its date and simple interest.