Brazil CDB Calculator

Estimate gross and net return for a fixed-rate or CDI-linked Brazilian CDB, including regressive IR, IOF and transparent assumptions.

How to estimate CDB return

Enter the amount, calendar-day term, business days and CDB rate type. For CDI-linked CDBs, use the CDI percentage and an annual CDI expectation you enter yourself.

The calculator converts the annual rate to a 252-business-day daily rate, estimates gross value, then deducts IOF and IR according to calendar-day term.

Fixed-rate CDB vs CDI-linked CDB

For fixed-rate CDBs, the simulation uses the annual fixed rate entered. For CDI-linked CDBs, the daily rate comes from your annual CDI expectation multiplied by the CDI percentage.

The tool does not fetch offers, rankings or current CDI; it only applies the assumptions you enter.

IR and IOF on CDB

IOF may reduce returns on short redemptions up to 30 calendar days under the regressive table from Decree 6,306/2007.

IR follows regressive rates of 22.5%, 20%, 17.5% or 15% by term and applies to positive yield after IOF.

What 100% of CDI means

A CDB at 100% of CDI follows the CDI rate used in the simulation. Since the rate is entered manually, the result depends directly on your annual CDI assumption.

FGC on CDB: what to watch

CDB/RDB appears among FGC-covered products, but the guarantee has limits, conditions and depends on the institution or conglomerate. Coverage does not change the return formula and does not remove every risk.

Official sources checked

Sources revalidated on 2026-06-26 for the current calculation version. The CDI shown in the calculator is not fetched from these sources.

Law 11,033/2004 - IRDecree 6,306/2007 - IOFBanco Central - SGSFGC - guarantee

Related calculators

Use other tools to compare fixed-income products or analyze cash flows.

Fixed income comparatorCompound interestIRR calculatorFixed income guide

Important notice

This tool estimates results from rates you enter. It does not fetch offers, recommend investments, or replace contract reading, income statements, or professional guidance.

FGC has limits and conditions; check the official source before investing.

Frequently asked questions

How do I estimate a CDB at 100% of CDI?
Enter 100 in % of CDI and provide your annual CDI expectation. The calculator applies that rate over 252 business days, then estimates IR and IOF by calendar-day term.
Does the calculator use the current CDI?
No. Annual CDI is a user-entered assumption; the tool does not fetch current rates or daily history.
When does IOF stop being charged?
Under the table used in this version, the rate reaches zero on day 30. For terms above 30 days, estimated IOF is zero.
Which IR rate applies to CDB?
The rate depends on calendar days: 22.5% up to 180 days, 20% from 181 to 360, 17.5% from 361 to 720 and 15% above 720 days.
Does CDB have FGC guarantee?
CDB/RDB appears among covered products, but the guarantee has limits and conditions. It does not change return or make every investment risk-free.
Do fixed-rate and CDI-linked CDBs use the same formula?
Both compound over business days, but the daily rate comes from different assumptions: annual fixed rate for fixed-rate CDBs and entered annual CDI times CDI percentage for CDI-linked CDBs.