What is the RBT12 and why does it matter?

RBT12 is the gross revenue accumulated over the previous 12 months (Receita Bruta dos últimos 12 meses). It determines which of the six progressive bands of the annex applies, so the same monthly sale can be taxed at a different effective rate depending on the company's recent turnover.

How is the effective rate (alíquota efetiva) calculated?

It uses the progressive formula ((RBT12 × nominal rate) − deduction) ÷ RBT12. The nominal rate and the fixed deduction (parcela a deduzir) come from the band table for the chosen annex. This avoids a tax cliff when revenue crosses a band boundary.

What are annexes I to V?

Annex I is commerce (retail), Annex II is industry, and Annexes III, IV and V cover different service activities. Each annex has its own six-band table of nominal rates and deductions, so picking the right annex is essential to an accurate result.

Does this include the Fator R for annexes III and V?

This tool computes the annex you select directly. The Fator R (payroll ÷ revenue ≥ 28%) can move some service activities between Annex III and Annex V; if your accountant applies it, choose the resulting annex here to get the correct rate.

Is this an official Simples Nacional calculation?

It implements the published progressive band tables and is accurate for planning, but it is not a substitute for the official PGDAS-D declaration. Always confirm with your contador before filing, as segregation of revenue types and credits can change the result.

Brazil Simples Nacional Tax Calculator

The Brazil Simples Nacional Tax Calculator turns your accumulated revenue into the effective tax rate (alíquota efetiva) and the monthly DAS payment under the unified Simples Nacional regime for micro-enterprises (ME) and small businesses (EPP). Rather than reading the wrong column of a printed table, you select your activity annex, enter your trailing 12-month revenue, and the tool applies the official progressive formula so the rate scales smoothly with turnover.

How it works

Simples Nacional uses six revenue bands per annex, each with a nominal rate and a fixed deduction (parcela a deduzir). The effective rate is never just the nominal rate — it is computed with the progressive formula:

effective rate = ((RBT12 × nominal rate) − deduction) ÷ RBT12
DAS = monthly revenue × effective rate

Here RBT12 is your gross revenue over the previous 12 months, which selects the band. Because the deduction grows with each band, a company that just crosses into a higher band is not suddenly taxed on its whole revenue at the higher nominal rate — only the marginal portion is. This is what stops a “tax cliff” at each boundary.

Example and notes

Suppose a retail shop (Annex I) has an RBT12 of R$ 500,000 and bills R$ 40,000 this month. The R$ 360,000.01–720,000.00 band has a nominal rate of 9.5% and a deduction of R$ 13,860. The effective rate is ((500000 × 0.095) − 13860) ÷ 500000 = 6.728%, so the DAS is 40000 × 6.728% = R$ 2,691.20.

Notes: the first band (up to R$ 180,000) has a zero deduction, so its effective rate equals its nominal rate. The annexes differ substantially — service annexes (IV and V) carry higher rates — so always confirm the correct annex for your activity, and remember the Fator R can shift some service businesses between Annex III and V.