PNU standard
The three letters were the state, by allocation: each DETRAN drew on a reserved block — Paraná opened the system with AAA to BEZ, São Paulo held BFA to GKI, Rio de Janeiro KMF to LVE — so the letters told you where a car was first registered.
In the sample, L stands for any letter and 9 for any digit.
1990–2020
issued for: car, van, truck, bus, trailer, semitrailer
Mercosur standard
Since December 2018 the seven characters say nothing at all: allocation is national and the plate shows no geography — a deliberate break after three decades of state-coded letters. The one fixed rule of the grammar: the last character must be a numeral.
In the sample, L stands for any letter and 9 for any digit.
2018 → today
issued for: car, van, truck, bus, trailer, semitrailer
Mercosur converted
Not a new allocation but an old one in disguise: every converted plate carries a letter A–J at the fifth position, the direct encoding of the digit it replaced on the vehicle's original grey plate.
The fifth character is the old plate's second digit in disguise — 0 became A, 1 B, through 9 J — so ABC-1234 returned as ABC1C34, its original number still readable underneath. The reverse doesn't hold: newly issued plates may carry A–J too.
In the sample, L stands for any letter and 9 for any digit.
2018 → today
issued for: car, van, truck, bus, trailer, semitrailer
Mercosur state arms
Issued only between March and November 2018, mostly in Rio de Janeiro — the only Brazilian plate since 1990 to show geography again: a state flag, a coat of arms, and the municipality's name at the right edge.
The letters were already meaningless — the geography moved into print: state flag, coat of arms and the municipality's name at the plate's edge, for just nine months of 2018. It is the last Brazilian plate that says where it is from.
In the sample, L stands for any letter and 9 for any digit.
2018–2018
issued for: car, van, truck, bus