A conta de luz está na mesa.

Yes, literally conta can mean account or bill, and luz means light. But in everyday Brazilian Portuguese, conta de luz is the normal way to say electricity bill.

This is just a fixed real-world expression:

• conta de luz = electricity bill
• conta de água = water bill
• conta de telefone = phone bill

So even though the literal words may seem odd in English, the phrase is completely natural in Portuguese.

Portuguese uses articles much more often than English does. So where English might say The bill is on the table, Portuguese naturally says A conta está na mesa.

Here a means the and agrees with conta, which is feminine:

• a conta
• a mesa

Leaving out the article would usually sound unnatural in this sentence.

Because de luz here expresses the type of bill, not a specific light.

Compare:

• conta de luz = electricity bill, light bill in general
• a conta da luz = the electricity bill, the bill for the electricity

So in a dictionary-style expression, Portuguese often uses de without the article:

• conta de água
• conta de internet
• sala de aula

If you are talking about one specific bill, you may also hear:

• A conta da luz está na mesa.

That is also very common.

Portuguese has two main verbs for to be: ser and estar.

Here, estar is used because the sentence talks about location:

• A conta de luz está na mesa. = The electricity bill is on the table.

A basic rule:

• ser = identity, definition, permanent characteristics
• estar = location, condition, temporary state

So for where something is, Portuguese normally uses estar.

Na is a contraction of:

• em = in / on / at
• a = the

So:

• em + a = na

That is why:

• na mesa = on the table / in the table area

Other common contractions:

• em + o = no
• em + os = nos
• em + as = nas

Examples:

• O livro está no carro.
• As chaves estão nas gavetas.

Portuguese em can cover meanings that English separates into in, on, and sometimes at, depending on context.

So:

• na mesa usually means on the table
• no carro means in the car
• na escola means at school

You usually learn the natural English translation from context. In this sentence, since a bill is physically resting on a table, na mesa is understood as on the table.

Exactly. Mesa is a feminine noun, so it takes feminine forms:

• a mesa
• na mesa = em + a mesa

Likewise, conta is also feminine:

• a conta

This is why the sentence has feminine agreement in both places.

A simple approximate pronunciation for an English speaker is:

ah KON-tah djee looz es-TAH nah MEH-zah

A few helpful notes:

• conta: stress on the first syllable
• de often sounds like djee in many Brazilian accents before some vowels? Not here, actually before l it is usually closer to jee/dji only in some casual speech? More safely, say dji is not ideal here. A better approximation is djee only before i. In de luz, many speakers say something closer to dji looz in casual Brazilian speech, but deh looz is also a useful learner approximation.
• luz ends with a z sound
• está has stress on the last syllable: es-TA
• mesa sounds like MEH-zah

If you want a more neutral learner-friendly version: ah KON-tah deh looz es-TAH nah MEH-zah

Yes. That is also correct.

Difference:

• na mesa = on the table / at the table area
• em cima da mesa = on top of the table

Em cima da mesa is more explicit. It clearly means the bill is physically on top of the table surface.

So:

• A conta de luz está na mesa. = natural and common
• A conta de luz está em cima da mesa. = more specific

Yes, but the original order is the most neutral:

• A conta de luz está na mesa.

You might also hear:

• Na mesa está a conta de luz.

That version emphasizes na mesa a bit more, and it sounds more marked or stylistic. In normal conversation, learners should stick with:

• A conta de luz está na mesa.

You would change the noun, article, and verb:

• As contas de luz estão na mesa. = The electricity bills are on the table.

Changes:

• a → as
• conta → contas
• está → estão

Notice that de luz stays the same.

Sometimes, yes, but conta de luz is the most everyday, widely natural expression in Brazil.

Related words:

• conta = bill
• fatura = invoice / bill, often used in more formal or specific contexts
• boleto = payment slip, depending on the situation

For a beginner, conta de luz is the safest and most natural phrase to learn first.

Yes, you can say A conta está na mesa if the context already makes it clear which bill you mean.

But the meaning changes slightly:

• A conta está na mesa. = The bill is on the table.
• A conta de luz está na mesa. = The electricity bill is on the table.

So de luz adds specific information.