Por - Rate or Unit

At its core, por acts as a mathematical link in your sentences. It establishes a relationship between two different sets of information. One set is usually a number or a frequency. The other set is a unit of time or measurement. In English, we often say "twice a week" or "five dollars a kilo". In Portuguese, you use por to create these same connections clearly. It tells the listener exactly how often something happens. It also explains the cost relative to a specific amount. Think of it like a grammar traffic light for your data. It regulates the flow of information between numbers and units. This helps you avoid confusion when ordering food or booking trips. It is a very logical and consistent pattern to learn.

1. 1Creating phrases with por is simple and follows a clear path.
2. 2Start with your primary action or quantity (e.g., três vezes).
3. 3Add the preposition por immediately after the quantity.
4. 4Follow up with the unit of time or measurement (e.g., semana).
5. 5If the unit needs a definite article, use a contraction.
6. 6Combine por + o to make the word pelo.
7. 7Combine por + a to make the word pela.
8. 8Use the plural versions pelos or pelas when necessary.
9. 9Remember that many common rates do not use articles at all.
10. 10For example, we usually say por hora rather than pela hora.
11. 11Keep the structure lean and direct for the best results.

You should reach for por in several specific real-world scenarios.

• Use it for speed limits like cem quilômetros por hora.
• Use it for your work schedule like oito horas por dia.
• It is perfect for frequency, such as duas vezes por mês.
• Use it at the grocery store for cinco euros por quilo.
• It works for distribution when you give um por pessoa.
• Use it for percentages like vinte por cento of a total.
• It is great for medication doses like um comprimido por dia.
• Use it for fuel efficiency such as dez quilômetros por litro.
• It helps in job interviews to discuss salário por mês.
• Use it when ordering coffee for a group at work.

There are times when por might seem right but is actually wrong.

• Do not use por to express a goal or a purpose.
• For example, use para when saying "this is for you".
• Avoid using por for a specific destination in most cases.
• Do not use it for "in order to" followed by a verb.
• If you are waiting for someone, use por (waiting for).
• However, do not confuse this with the rate or unit rule.
• Using por for a deadline is also a common mistake.
• For deadlines, you should usually use the preposition para.
• Think of para as a destination and por as a rate.
• If you mix them up, your meaning might change completely.

Everyone makes mistakes, so do not worry too much about them.

• A frequent error is forgetting the contractions like pelo or pela.
• People often use a instead of por for frequency.
• Saying duas vezes a semana sounds like a direct English translation.
• In Portuguese, duas vezes por semana is the correct way.
• Another mistake is adding an article where it is not needed.
• Saying por o dia instead of por dia is quite common.
• Some learners use cada and por in the same short phrase.
• Um por cada pessoa is repetitive and sounds a bit strange.
• Just say um por pessoa to keep it simple and clean.
• Even advanced students might forget por in fast-paced conversations.

You might wonder about the difference between por and cada.

• Both words help you talk about units and distribution.
• Cada means "each" and usually comes before the noun.
• Por means "per" and usually follows a specific quantity.
• You can say cinco euros cada or cinco euros por quilo.
• Use por when you have a clear rate of exchange.
• Use cada when you want to emphasize individual items separately.
• Also, contrast por with the preposition a in specific phrases.
• Some older expressions use a, but por is more modern.
• Por cento is the standard way to say "percent" today.
• Choosing the right one makes your Portuguese sound very professional.