Only whether works directly before or not, after a preposition, before a to-infinitive, and as the subject of a sentence, as in it depends on whether you’re ready or I can’t decide whether to go. Only if is possible in real conditionals, as in if it rains, we’ll stay home.
Grammar Rule
Whether and if are often interchangeable, but only whether works in four specific structures, and only if is possible in real conditionals.
Whether vs If (Advanced): Rules and Examples
| Structure | Only works with | Example |
|---|---|---|
| + or not (directly after) | whether | I don’t know whether or not it will rain. |
| After a preposition | whether | It depends on whether you’re ready. |
| Before a to-infinitive | whether | I can’t decide whether to go. |
| As subject of the sentence | whether | Whether we succeed depends on hard work. |
| Real conditional | if | If it rains, we’ll stay home. |
Remember: only whether before or not, after prepositions, before to-infinitives, or as subject; only if in real conditionals.
Practice Test
Instructions
Answer each question in the test below choosing correctly between whether and if. You will get a new random set of questions every time you retake the test, plus a downloadable results summary with your name and score at the end.
B2-52. Whether vs If
No necesitas registrarte para empezar. Al finalizar verás tu calificación de inmediato, y si quieres podrás agregar tu nombre para personalizar y descargar tu resultado.
Frequently Asked Questions
Which word must you use before or not?
Whether, as in I don’t know whether or not it will rain.
Which word must you use after a preposition?
Whether, as in it depends on whether you’re ready.
Which word must you use before a to-infinitive?
Whether, as in I can’t decide whether to go.
Which word must you use in a real conditional?
If, as in if it rains, we’ll stay home.