Turn this distinction into automatic recall
Falando teaches Brazilian Portuguese through grammar, vocabulary, audio, examples, and spaced review, so confusing pairs stop feeling like guesses.
Quick answer
Diminuir often describes something becoming less. Reduzir often presents deliberate action toward a lower target.
A reliable test is to identify the job of the word before translating from English.
What each word does
diminuir
to decrease, lessen, or become smaller
Use diminuir for a quantity, sound, speed, pain, or intensity going down.
reduzir
to reduce or cut
Use reduzir for deliberately bringing a quantity, cost, risk, or scope down to a lower level.
How to choose
- diminuir: Choose diminuir if the sentence points to a quantity, sound, speed, pain, or intensity going down.
- reduzir: Choose reduzir if the sentence points to deliberately bringing a quantity, cost, risk, or scope down to a lower level.
Examples
A chuva diminuiu à tarde.
The rain eased in the afternoon.
Precisamos reduzir o desperdício.
We need to reduce waste.
Common trap
Both can be transitive or intransitive in many contexts. Reduzir sounds more planned or technical; diminuir is broader in daily speech.
Practice it in context
Pick one sentence from your real life and write it twice: once with diminuir, then once with reduzir. If both versions feel possible, name the meaning shift.
Turn this distinction into automatic recall
Falando teaches Brazilian Portuguese through grammar, vocabulary, audio, examples, and spaced review, so confusing pairs stop feeling like guesses.