Convert BST (British Summer Time) to BRT (Brasília Time)

Which BST is this?

BST names more than one zone. This page reads it as British Summer Time at UTC+1, which is the reading most converters take. There is one other: Bangladesh Standard Time at UTC+6, used in Bangladesh, all year.

The letters on a meeting invitation do not say which one is meant. If yours is not British Summer Time, the answer above is wrong, and not by a little:

Any converter has to pick one of these readings before it can answer, and two of them can pick differently — a page of search results for a BST conversion can show you both answers with neither being wrong. The one to trust is whichever states the zone it means rather than only the letters. Where it matters, ask which country the sender is in.

Best time to schedule a meeting

Standard 9–5 working hours overlap for 4 hours: 1:00 PM–5:00 PM BST (9:00 AM–1:00 PM BRT). Schedule meetings inside that window.

BST to BRT conversion table

About BST

British Summer Time (BST) is UTC+1. It is used in the UK from late March to late October.

British Summer Time is UTC+1, in force in the UK and Ireland from the last Sunday in March to the last Sunday in October. The abbreviation is ambiguous: BST also means Bangladesh Standard Time, UTC+6, five hours away. Within the UK it is the reason "GMT" is wrong for most of the year — the clocks are on BST from spring to autumn, and only the winter half of the year is actually GMT.

About BRT

Brasília Time (BRT) is UTC−3. It is used in São Paulo, Rio de Janeiro and most of populated Brazil.

Brasília Time is UTC−3, covering São Paulo, Rio de Janeiro and Brasília. Brazil abolished daylight saving in 2019, so the offset is now fixed year-round — but a great deal of older software, and a lot of published advice, still assumes the southern-hemisphere shift that used to run from October to February. If a Brazilian meeting time was correct last year and is an hour out now, an out-of-date time zone database is the likely cause.

Does this gap change with the seasons?

This gap is seasonal. The abbreviations themselves are fixed offsets, but the region on BST switches to GMT (UTC+0) from late October to late March. So the 4-hour figure on this page is correct for the part of the year when both places are actually on these abbreviations, and changes by an hour outside it.

BRT does not shift, so the whole change comes from one side. A recurring meeting fixed in BRT will appear to move by an hour for everyone on the other side, twice a year, without anyone changing anything.

This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.

Frequently asked questions