To vs. Too
“To” and “too” sound alike but have different grammatical jobs. “To” functions as a preposition and in the to-infinitive, while “too” is an adverb that can mean “also” or “more than enough.”
Use “to” as a preposition or infinitive marker; use “too” for meanings such as “also” or “more than enough.”
Key details
Choose the right form
| Meaning/function | Use | Example pattern |
|---|---|---|
| preposition or infinitive marker | to | to London / to write |
| also or more than enough | too | me too / too expensive |
Further guidance
Core difference
Use “to” before a destination/receiver or as part of a to-infinitive; use “too” for “also” or for excess/degree.
Fast Test
If you can substitute “also” or “more than enough,” choose “too.” Otherwise check whether the word is the preposition/infinitive marker “to.”
Usage Boundary
The words are homophones in ordinary pronunciation, so sound alone cannot choose the spelling.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- to — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct grammar-reference evidence that to functions as a preposition and as the marker in the to-infinitive.
- too — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct dictionary and grammar evidence for too as an adverb meaning more than enough, also, or related degree senses.