Я всё понял верно.

• Я = I
• всё = everything
• понял = understood
• верно = correctly / right

So the sentence is literally I understood everything correctly.

Понял is the past tense of the perfective verb понять.

That means it refers to a completed result: I understood / I got it.

Compare:

• понимаю = I understand / I am understanding now, in general
• понимал = I was understanding / I used to understand / I understood in an ongoing or descriptive sense
• понял = I understood / I got it as a completed event

In this sentence, the speaker is talking about reaching understanding, so понял is the natural choice.

Yes. In Russian, past tense verbs are formed with -л, and they agree in gender and number, not person.

Here:

• понял = masculine singular
• поняла = feminine singular
• поняло = neuter singular
• поняли = plural

So if a man says this, he says Я всё понял верно.
If a woman says it, she says Я всё поняла верно.

Notice that the verb form itself does not show I/you/he in the past tense, which is one reason Я is often included.

These are different words, even though in casual writing ё is often written as е.

• всё = everything
• все = all / everyone

So here всё is correct because the meaning is everything.

Examples:

• Я всё понял. = I understood everything.
• Все поняли. = Everyone understood.

Also, всё is pronounced with ё: roughly vsyo.

It is the direct object of понял, so it is in the accusative case.

However, with всё, the accusative looks the same as the nominative, so you do not see a form change.

You can think of it as:

• что? = what?
• понял что? = всё

So: I understood what? Everything.

Here верно means correctly, accurately, or right.

It is very close to правильно, and in many situations they are interchangeable.

• Я всё понял верно.
• Я всё понял правильно.

Both mean roughly I understood everything correctly.

A small nuance:

• правильно is the more common everyday word for correctly
• верно can sound a bit more like accurately / properly / that’s right

In this sentence, верно sounds natural and slightly concise.

Russian word order is flexible, but different orders sound more or less natural depending on emphasis.

Я всё понял верно is a normal order, with верно placed at the end as the final piece of information: correctly.

Other possible orders:

• Я верно всё понял.
• Я всё верно понял.

These are also grammatical, but the emphasis shifts slightly.

A very common neutral conversational version is:

• Я всё правильно понял? = Did I understand everything correctly?

So the word order in your sentence is natural, but not the only possibility.

Sometimes, yes, but in this sentence Я is often kept.

Because past tense Russian verbs do not show person clearly, понял by itself could mean:

• I understood
• you understood in some contexts
• he understood

So Я helps make the subject explicit.

If the context is already very clear, a speaker might say simply:

• Всё понял верно.

But standing alone, Я всё понял верно is clearer and more complete.

In practice, it means I understood everything correctly.

English can place correctly in different spots, but the Russian sentence is about the quality of the understanding: the speaker got the meaning right.

So the natural interpretation is:

• I understood everything correctly
• I got everything right

Yes, but the meaning changes.

• Я всё понял верно. = I understood everything correctly
• Я понял верно. = I understood correctly / I got it right

Without всё, the sentence becomes more general and less explicit about everything.

In real conversation, Russian often drops words that are understood from context, so Я понял верно can work, but всё makes it clear that the speaker means the whole thing.

A simple learner-friendly pronunciation is:

ya fsyo POH-nyal VYER-na

A few useful notes:

• Я sounds like ya
• всё sounds like fsyo
• понял is stressed on the first syllable: ПО-нял
• верно is stressed on the first syllable: ВЕР-но

The letter ё in всё is important for pronunciation, even though Russians often write все instead of всё in informal text.