Question 1

Why is the effective rate different from the table's nominal rate?

Accepted Answer

The nominal rate is only the formula's starting point, it represents the tax that would be owed if RBT12 sat exactly at that bracket's ceiling. For any RBT12 below the ceiling, the deductible amount lowers the result, so the real effective rate, computed as (RBT12 x nominal rate - deductible amount) / RBT12, is always lower than or equal to the nominal one. Applying the nominal rate directly, without subtracting the deductible amount, is the most common mistake in informal calculators and always overstates the tax.

Question 2

What is the Payroll Factor and how does it choose between Annex III and Annex V?

Accepted Answer

The Payroll Factor is the ratio between payroll over the last 12 months (including owner's pro-labore and payroll charges) and RBT12. For the service activities listed in article 17 item V of LC 123/2006, a Payroll Factor of 28% or higher puts the business in Annex III, which has lower rates because CPP (employer social security) is already included in the DAS itself; below 28%, the business falls under Annex V, with higher rates because CPP is paid separately, on actual payroll. The calculator shows exactly how much more payroll, in reais, is needed to cross that 28% threshold.

Question 3

Does every service activity get tested against the Payroll Factor?

Accepted Answer

No. Only the activities listed in article 17 item V (for example, physiotherapy, insurance brokerage, expert appraisal, real estate management and leasing, and the general "other services" catch-all not covered elsewhere) are tested by the Payroll Factor to choose between Annex III and V. Services listed under item III (such as travel agencies, gyms and schools) always fall under Annex III, regardless of payroll; services under item VI (such as construction, cleaning and security) always fall under Annex IV.

Question 4

What is RBT12 and why does it determine the bracket?

Accepted Answer

RBT12 is the total gross revenue accumulated over the 12 months prior to the assessment month (it is not calendar-year revenue, it is a rolling window). It is this accumulated revenue, not a single month's revenue, that determines which of the six brackets in each annex the business falls under, and therefore which nominal rate and deductible amount apply that month.

Question 5

How does the DAS breakdown across taxes work?

Accepted Answer

The total amount paid in the DAS is internally split across up to eight taxes (IRPJ, CSLL, COFINS, PIS/Pasep, CPP, ICMS, IPI and ISS), using official percentages that vary by annex and bracket. Annex IV never allocates CPP (employer social security is collected outside the DAS, on actual payroll), and the same applies to Annex V. Only Annexes I and II allocate ICMS, and among those, only Annex II allocates IPI; only Annexes III, IV and V allocate ISS.

Question 6

What is the R$3.6 million sub-cap?

Accepted Answer

It is the accumulated revenue threshold above which ICMS and ISS stop being collected inside the DAS and instead follow the regular state or municipal rules (LC 123/2006 art. 19-A), even though the business stays in Simples Nacional (the regime's overall ceiling is R$4.8 million). Between R$3.6 million and R$4.8 million in RBT12, the business remains in Simples for federal taxes but must assess ICMS/ISS separately under its state's or municipality's own rules; this calculator flags when that threshold is crossed.

Question 7

How do I know when my business will move to a different bracket?

Accepted Answer

In DAS mode, enter the monthly revenue you expect to keep going forward in the projection field: the calculator simulates RBT12 moving month by month (replacing the oldest month in the 12-month window at each step, exactly as the rule works) and shows in how many months, at that pace, the bracket should change.

Question 8

Does the calculator handle the full Simples assessment, including the residual ICMS/ISS above the sub-cap?

Accepted Answer

Not entirely. It accurately reproduces the effective-rate formula, the Payroll Factor, and the standard per-tax breakdown, but once RBT12 crosses the R$3.6 million sub-cap, there is a separate formula (article 21 of Annexes I/III/IV/V) for assessing the residual ICMS/ISS on the slice of revenue below the sub-cap, which this calculator does not reproduce, it only flags that the effect exists. In that scenario, treat the result as an approximation and confirm the exact assessment with the business's accountant.

Simples Nacional Tax Calculator

Simples Nacional Calculator

The real effective rate, not the bracket's nominal one

Three modes for the three most common Simples Nacional decisions

Use this tool on your site

Sources and references for this tool

Frequently asked questions

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Simples Nacional Tax Calculator

Simples Nacional Calculator

The real effective rate, not the bracket's nominal one

Three modes for the three most common Simples Nacional decisions

Use this tool on your site

Sources and references for this tool

Frequently asked questions

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Simples Nacional Calculator

The real effective rate, not the bracket's nominal one

Three modes for the three most common Simples Nacional decisions

Use this tool on your site

Sources and references for this tool

Frequently asked questions

Where to go next

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Simples Nacional Calculator

The real effective rate, not the bracket's nominal one

Three modes for the three most common Simples Nacional decisions

Use this tool on your site

Sources and references for this tool

Frequently asked questions

Where to go next

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