Нет бы мне измерить дверной проём — шкаф не поместился.

In this sentence, нет бы is a fixed colloquial expression used to show regret, annoyance, or criticism about something someone should have done but didn’t do.

So:

Нет бы мне измерить дверной проём
roughly means:
I should have measured the doorway / If only I had measured the doorway / Why didn’t I just measure the doorway?

This is not the ordinary literal meaning of нет. In this pattern, нет бы + dative + infinitive, the whole phrase acts like an idiomatic way to comment on a missed sensible action.

It often sounds slightly emotional, self-critical, or reproachful.

Examples:

• Нет бы спросить заранее. — I should have asked beforehand.
• Нет бы тебе позвонить! — You should have called! / Why didn’t you call?

Because in the construction нет бы + person in dative + infinitive, the person who was supposed to do the action is usually put in the dative.

So:

• мне = for me / as for me
• измерить = to measure

Together, нет бы мне измерить means something like:

• I should have measured
• Why didn’t I measure?

This dative + infinitive structure is common in Russian in impersonal or semi-impersonal expressions.

Compare:

• Мне пора идти. — It’s time for me to go.
• Тебе бы отдохнуть. — You should rest.
• Нет бы мне проверить размеры. — I should have checked the dimensions.

Because after нет бы, Russian normally uses the infinitive, not a finite verb.

Structure:

• нет бы + dative + infinitive

So Russian says literally something closer to:

• No, for me to measure the doorway... but idiomatically:
• I should have measured the doorway.

This is just how the construction works. You do not normally say:

• Нет бы я измерил... in this meaning.

The infinitive presents the action as the thing that would have been sensible to do.

Измерить is the perfective infinitive. Here that makes sense because the speaker is talking about a single completed action they should have done once: measure the doorway.

• измерить = to measure once / to take the measurement
• измерять = to be measuring / to measure repeatedly / as a process

Since the meaning is I should have measured it (before bringing the шкаф), perfective is the natural choice.

Compare:

• Надо было измерить дверной проём. — I should have measured the doorway.
• Он долго измерял дверной проём. — He was measuring the doorway for a long time.

Because дверной проём means the doorway / door opening, which is exactly what matters when checking whether furniture will fit through.

• дверь = the door itself
• дверной проём = the opening in the wall for the door

If you are moving a wardrobe, the important thing is usually the width/height of the opening, not the physical door panel.

So:

• измерить дверь could mean measure the door itself
• измерить дверной проём means measure the opening to see whether something can pass through

It is in the accusative case, because it is the direct object of измерить.

The infinitive измерить takes a direct object:

• измерить что? — measure what?

Answer:

• дверной проём

Because проём is an inanimate masculine noun, its accusative singular looks the same as the nominative singular:

• nominative: дверной проём
• accusative: дверной проём

So the form does not change, even though the case function is accusative.

Yes, шкаф не поместился means the wardrobe/cabinet didn’t fit.

The verb is поместиться, a perfective verb meaning:

• to fit
• to be accommodated
• to be able to go into a space

So here it means the шкаф could not fit through the doorway / into the available space.

A useful contrast:

• помещаться — imperfective, general or repeated ability
  Шкаф не помещается. — The wardrobe doesn’t fit.
• поместиться — perfective, result in a specific situation
  Шкаф не поместился. — The wardrobe didn’t fit.

In this sentence, the speaker is talking about a completed real-life outcome, so perfective past is natural.

The dash connects two closely related thoughts:

1. Нет бы мне измерить дверной проём
2. шкаф не поместился

The second part gives the consequence or reason for the regret in the first part.

So the dash works a bit like:

• and as a result
• because in the end
• turns out

Natural English equivalents:

• I should have measured the doorway — the wardrobe didn’t fit.
• If only I’d measured the doorway: the wardrobe didn’t fit.

In Russian, the dash is often used to link clauses dramatically or expressively, especially in colloquial writing.

Yes, Нет бы мне измерить дверной проём — шкаф не поместился is fairly colloquial and expressive.

A more neutral version would be something like:

• Надо было измерить дверной проём: шкаф не поместился.
• Мне следовало измерить дверной проём: шкаф не поместился.

Comparison:

• Нет бы мне измерить... — colloquial, emotional, self-reproachful
• Надо было измерить... — common, neutral
• Мне следовало измерить... — more formal/bookish

So if you want everyday spoken regret with a slight emotional flavor, нет бы is very natural.

Yes. It can be used about yourself, someone else, or even in a more general way.

Examples:

• Нет бы мне проверить адрес. — I should have checked the address.
• Нет бы тебе предупредить! — You should have warned me!
• Нет бы ему позвонить заранее. — He should have called in advance.

The person is typically in the dative:

• мне
• тебе
• ему
• нам, etc.

Very often this sounds like mild criticism or exasperation.

Yes, but the given order is very natural.

Current sentence:

• Нет бы мне измерить дверной проём — шкаф не поместился.

Possible variations:

• Нет бы мне дверной проём измерить — шкаф не поместился.
• Шкаф не поместился — нет бы мне измерить дверной проём.

But the original version is the smoothest and most standard for this idea.

Russian word order is flexible, but changing it changes the emphasis:

• putting шкаф не поместился first highlights the bad result first
• keeping измерить дверной проём together makes the missed action clear and easy to process

So learners should treat the original order as the best default.

Yes, шкаф can mean different kinds of tall storage furniture depending on context:

• wardrobe
• closet
• cabinet
• cupboard

In this sentence, the exact English word depends on the situation. Since it’s about not fitting through a doorway, wardrobe or cabinet are both plausible translations.

The important thing for the Russian is simply:

• шкаф = a large piece of furniture used for storage

So the grammar and meaning of the sentence do not depend on choosing one exact English furniture word.