El recargo aumenta el cargo total.

Because both are masculine singular nouns.

• el recargo = the surcharge / the extra fee
• el cargo = the charge / fee
• total describes cargo, so el cargo total = the total charge

In Spanish, nouns usually need an article when you are talking about a specific thing in a general statement like this.

They are related, but they are not the same.

• cargo = a charge, fee, or amount billed
• recargo = an extra charge added on top of that, often a surcharge or markup

A helpful way to think about re- here is that it suggests something added back/on top. So:

• cargo total = the total charge
• recargo = the extra amount that increases it

Because the subject is el recargo, which is singular.

So the structure is:

• El recargo = subject
• aumenta = third-person singular verb
• el cargo total = direct object

If the subject were plural, then you would use aumentan:

• Los recargos aumentan el cargo total.

Aumenta is the third-person singular present tense of aumentar.

Conjugation in the present:

• yo aumento
• tú aumentas
• él/ella/usted aumenta
• nosotros aumentamos
• ustedes/ellos aumentan

In this sentence, el recargo is like it, so Spanish uses aumenta.

Because Spanish does not usually use a helping verb like do/does in simple present statements.

English:

• The surcharge increases the total charge.

Spanish:

• El recargo aumenta el cargo total.

The single verb aumenta already carries the meaning of increases.

In Spanish, adjectives often come after the noun.

So:

• cargo total = total charge

This is the most normal order. Putting total before the noun can sometimes change the tone or emphasis, but here el cargo total is the standard, natural phrasing.

Yes, but they sound a little different.

• incrementa sounds more formal or technical
• sube is more everyday and less formal
• aumenta is a very solid neutral choice

So all of these are possible depending on context, but aumenta works very well in billing, finance, or general explanatory language.

It is understandable, but depending on context, other phrases may be even more common.

Possible alternatives include:

• el total
• el costo total
• el importe total
• el total a pagar

For example, on a bill or checkout page, you might often see:

• El recargo aumenta el total a pagar.

Still, el cargo total is grammatically correct and understandable.

Yes. Cargo has several meanings, which can confuse learners.

Common meanings include:

• charge / fee in financial contexts
• position / post / role in work or government contexts

For example:

• un cargo bancario = a bank charge
• un cargo público = a public office / public position

So context is very important. In your sentence, cargo clearly refers to a financial charge.

A couple of things:

• The r in recargo is a single r sound, not a strong rolled rr
• The g in cargo and recargo is a hard g sound, like in go
• Stress:
  • recargo
  • aumenta
  • cargo
  • total

So a natural pronunciation would sound roughly like:

• ehl reh-KAR-goh ow-MEN-tah ehl KAR-goh toh-TAL

No. This sentence clearly says that the surcharge causes the total charge to increase.

That is because of the sentence structure:

• El recargo = the thing doing the action
• aumenta = increases
• el cargo total = the thing being increased

So the surcharge is the cause, not just something that exists while the total increases.

Yes, that would be wrong in standard Spanish.

You should say:

• El recargo aumenta el cargo total.

No a is needed because el cargo total is the direct object, not an indirect object.

The personal a is generally used with people or sometimes personified beings, not with things like cargo total.