Если не заплатить штраф вовремя, сумма будет выше.

Because this is an impersonal, general condition. Russian often uses если + infinitive in notices, rules, and formal statements when the subject is not named.

So Если не заплатить штраф вовремя... means something like:

• If the fine is not paid on time...
• If you do not pay the fine on time...
• If one does not pay the fine on time...

It sounds neutral and general, which fits official-style language.

Yes, in a sense. The sentence does not explicitly say who fails to pay. The subject is left generic.

That is very common in Russian, especially in:

• instructions
• warnings
• regulations
• public notices

So the sentence is not specifically about I, you, or they. It applies to anyone in that situation.

Because the sentence is about a single completed action: paying the fine by a deadline.

• заплатить = to pay, to complete the payment
• платить = to pay / be paying / pay repeatedly or in general

Here the important idea is whether the payment gets completed on time, so the perfective verb заплатить is the natural choice.

Here штраф is the direct object of заплатить, so it is in the accusative case.

For an inanimate masculine singular noun, the accusative looks exactly like the nominative. So:

• nominative: штраф
• accusative: штраф

That is why the form does not visibly change.

Вовремя means on time, in time, or before the deadline.

In this sentence it means the fine must be paid before the allowed time runs out.

A useful detail: вовремя is written as one word.

Сумма means the amount or the total sum due.

The idea is that if you pay late, the amount you have to pay becomes larger. In English we might say:

• the amount will be higher
• the total will be higher

Using сумма makes the meaning a little broader and more natural in formal language, since the payable amount may increase because of penalties, fees, or interest.

This is the normal way to say will be higher.

• будет = will be
• выше = higher

Выше is the comparative form, and Russian often uses it after быть in sentences about prices, levels, and amounts.

So:

• сумма выше = the amount is higher
• сумма будет выше = the amount will be higher

Yes. Russian can say:

Если не заплатить штраф вовремя, то сумма будет выше.

The word то means something like then in this structure. But it is often omitted, especially when the meaning is already clear.

So both versions are correct:

• Если не заплатить штраф вовремя, сумма будет выше.
• Если не заплатить штраф вовремя, то сумма будет выше.

Because the sentence begins with a subordinate clause introduced by если.

Russian punctuation normally separates:

• the if-clause
• the main clause

So:

• Если не заплатить штраф вовремя, сумма будет выше.

This is directly parallel to English punctuation in sentences like:

• If you do not pay on time, the amount will be higher.

Yes. Russian word order is flexible, and the meaning stays basically the same.

For example:

• Если не заплатить штраф вовремя, сумма будет выше.
• Сумма будет выше, если не заплатить штраф вовремя.

The second version puts the result first and the condition second. Russian does this quite naturally.

Yes, absolutely.

• Если не заплатить штраф вовремя... = general, impersonal, formal
• Если не заплатите штраф вовремя... = directly addressed to you

So if a notice is speaking personally to the reader, it might use:

Если не заплатите штраф вовремя, сумма будет выше.

That sounds more direct, while the original sentence sounds more official and detached.