Is the word quantidade the same in Brazilian and European Portuguese?

Yes

The word "quantidade" is identical in meaning, spelling, and grammar in both Brazilian and Continental Portuguese. The only differences are pronunciation and phonetic rhythm:

• Brazilian Portuguese: Vowels are generally more open and clearly articulated. The letter "d" in "quantidade" is often palatalized, sounding like "dj" (e.g., quan-ti-da-dji), especially in many coastal and urban dialects.
• Continental Portuguese: Vowels are much more "closed" or reduced. Unstressed vowels are often swallowed or nearly silent, making the word sound more clipped and rhythmic. The "d" remains a dental/alveolar sound, not a "dj" sound.

Brazilian Portuguese Examples

1. A quantidade de açúcar está muito alta. (The amount of sugar is very high.)
2. Tem uma quantidade enorme de gente aqui. (There is an enormous quantity of people here.)
3. Você viu a quantidade de lixo na praia? (Did you see the amount of trash on the beach?)
4. A quantidade de dinheiro que ele tem é muita. (The amount of money he has is a lot.)
5. Tem uma quantidade enorme de fotos no celular. (There is an enormous quantity of photos on the cell phone.)

Continental Portuguese Examples

1. A quantidade de açúcar está muito elevada. (The amount of sugar is very high.)
2. Há uma quantidade enorme de pessoas aqui. (There is an enormous quantity of people here.)
3. Viste a quantidade de lixo na praia? (Did you see the amount of trash on the beach?)
4. O montante de dinheiro é muito grande. (The amount of money is very large.)
5. Há uma quantidade enorme de fotografias no telemóvel. (There is an enormous quantity of photos on the mobile phone.)