Through or Thru: Which Is Correct?
Updated · Which One Is Correct editorial team
Quick answer: When deciding between through and thru, you must know which is the correct choice for your context. Through is the standard spelling used in formal writing and most situations. Thru is an informal variant reserved for signs, abbreviations, and specific phrases like drive-thru. Using the standard form ensures your writing looks professional and clear to all readers.
The Short Answer
Through is the standard spelling; thru is an informal variant used on signs and in drive-thru.
People often confuse these because they sound identical and both appear in everyday language. The visual difference matters less than the register, as using the informal form in a formal letter can seem unprofessional or careless to the reader.
Side-by-Side Comparison
| Form | Status | Use it when |
|---|---|---|
| through | Standard | Formal writing and general communication |
| thru | Informal | Road signs and casual abbreviations |
| through | Noun | Indicating a complete passage from one side to another |
| thru | Noun | Rarely used as a noun even in casual contexts |
Correct Example Sentences
- The light traveled through the glass window to reach the floor.
- We need to drive through the busy intersection carefully.
- She called through the receiver to ask for directions.
- The road goes through the center of the city quickly.
- Please go through the door to enter the room.
- The rain poured through the cracks in the wall.
- We will meet through the tunnel at noon.
- The beam shone through the dark night sky.
- You must go through the gate to get to the park.
- This tunnel runs through the entire mountain range.
Common Mistakes and Fixes
- I will send you an email thru this afternoon.
- I will send you an email through this afternoon.
- The car drove thru the tunnel without stopping.
- The car drove through the tunnel without stopping.
- She walked thru the crowded market to find her friend.
- She walked through the crowded market to find her friend.
- We must go thru the security checkpoint before boarding.
- We must go through the security checkpoint before boarding.
- The light shines thru the window all day long.
- The light shines through the window all day long.
- Please sign the document thru the post office.
- Please sign the document through the post office.
Related Word Pairs
- Whether or Whether:
- Whether introduces a clause while or joins two words.
- Then or Than:
- Then indicates time whereas than compares options.
- Affect or Effect:
- Affect is a verb and effect is a noun.
- Fewer or Less:
- Fewer counts items and less measures volume.
- Your or You're:
- Your shows possession and you're is short for you are.
- They're or There:
- They're contains an apostrophe and refers to people while there refers to a place.
- Its or It's:
- Its shows possession and it's short for it is.
- Who or Whom:
- Who asks about a subject and whom asks about an object.
Frequently Asked Questions
Is thru ever correct to use?
Thru is technically incorrect in formal writing but acceptable on street signs and in casual contexts like drive-thru or phone-thru. It functions as an accepted abbreviation in specific informal settings where space is limited or style is casual.
