Taxa anual vs. anuidade
While both terms effectively translate to "annual fee" in English, usage depends on context. Taxa anual is a broad descriptive term for any rate or charge applied yearly, often involving percentages. Anuidade is a specific noun usually referring to a subscription-style payment required to maintain a service, such as a credit card or professional license.
Taxa anual
B1Taxa anual implies a general rate, percentage, or administrative charge calculated on a yearly basis. It is commonly used when discussing interest rates (like APR), taxes, or specific service charges.
A taxa anual de juros deste empréstimo é de 10%.
(The annual interest rate of this loan is 10%.)
A prefeitura cobra uma taxa anual para a licença de funcionamento.
(The city hall charges an annual fee for the operating license.)
Verifique qual é a taxa anual efetiva antes de investir.
(Check what the effective annual rate is before investing.)
Esta escola cobra uma pequena taxa anual de materiais.
(This school charges a small annual materials fee.)
Anuidade
B2Anuidade is the specific name given to the recurring payment made to keep a contract or membership active for a year. It is the standard word for credit card fees and professional association dues.
Estou procurando um cartão de crédito sem anuidade.
(I am looking for a credit card without an annual fee.)
Os médicos precisam pagar a anuidade ao conselho todos os anos.
(Doctors need to pay the annual fee to the board every year.)
A anuidade desta revista ficou mais cara.
(The annual subscription fee for this magazine became more expensive.)
Você pode parcelar a anuidade em doze vezes.
(You can pay the annual fee in twelve installments.)
Summary
In short, use anuidade when talking about the specific price you pay to a gym, a credit card company, or a professional board to stay a member for the year. Use taxa anual when referring to interest rates, government taxes, or general administrative charges that occur once a year.