Whether or Not: When You Need "Or Not" (and When You Don't)
You need or not after whether when you mean "regardless of whether": The match will go ahead whether or not it rains. You can usually drop or not when whether simply means "if" and introduces a yes/no question: I don't know whether she's coming.
Remove or not from the first sentence and it breaks: "The match will go ahead whether it rains" is incomplete. Remove it from the second and nothing is lost. That simple deletion test answers most questions about this phrase.
Quick answer: Keep or not when the sentence means "no matter whether" (We're leaving at six whether or not you're ready). Drop it when whether introduces an indirect question or choice (She asked whether the shop was open). If removing or not leaves the sentence complete, it's optional and usually better left out.
On this page
Two jobs that "whether" does
Whether is a conjunction that introduces alternatives. The confusion comes from the fact that it introduces two different kinds of clause.
Job 1: an indirect question or choice (noun clause)
Here whether means "if" and the clause acts like a noun, often the object of a verb.
- I wonder whether he's awake.
- We haven't decided whether we'll move to Melbourne.
- Whether the plan works depends on funding.
In each case, the clause answers the question "what?": I wonder what? We haven't decided what? The alternatives ("or not") are already built into the meaning, so adding or not is redundant, though not ungrammatical.
Job 2: "regardless of whether" (adverb clause)
Here whether introduces a condition that does not change the outcome. The clause acts like an adverb, modifying the whole sentence.
- I'm going to the gym whether or not I feel like it.
- Whether or not you approve, the decision is final.
These sentences say the main action happens either way. The or not is essential, because it states the second alternative. Without it, the sentence feels unfinished: "I'm going to the gym whether I feel like it" sounds as if a word is missing.
The deletion test
To decide whether you need or not, delete it and reread the sentence.
| Sentence | Without "or not" | Verdict |
|---|---|---|
| Let me know whether or not you can come. | Let me know whether you can come. | Optional; usually drop it |
| Whether or not you come, we'll start at seven. | Whether you come, we'll start at seven. | Required; keep it |
| She asked whether or not the train was late. | She asked whether the train was late. | Optional; usually drop it |
| The event is on whether or not it's sunny. | The event is on whether it's sunny. | Required; keep it |
| Whether or not the results are valid is unclear. | Whether the results are valid is unclear. | Optional; usually drop it |
If the shortened version still says exactly what you meant, cut the extra words. If it sounds broken or changes meaning, keep them.
Is "or not" ever useful in noun clauses?
Yes. Even when or not is technically optional, writers sometimes keep it for emphasis, to stress that both outcomes are in play: You need to decide whether or not you're committed to this. Here the extra words underline that "not committed" is a real option. That is a legitimate stylistic choice. The point is to use or not deliberately, not by habit.
Where to put "or not"
When or not is needed, you have two correct positions.
- Together: whether or not it rains
- Split: whether it rains or not
Both are standard. The split version is common in speech and works well when the clause is short. When the clause is long, keeping or not next to whether is clearer, because the reader doesn't have to wait for the alternative:
- ✅ Whether or not the council approves the new cycling lanes along the river, construction will begin in spring.
- Awkward: Whether the council approves the new cycling lanes along the river or not, construction will begin in spring.
Whether vs if
In casual English, if often replaces whether in indirect questions: I asked if she was free. That is acceptable in most contexts, including professional writing. But there are places where only whether works.
| Situation | Use whether | If possible? |
|---|---|---|
| After a preposition | We argued about whether to go. | ✘ No (about if to go) |
| Before a to-infinitive | I can't decide whether to stay. | ✘ No (if to stay) |
| Directly before or not | Tell me whether or not you agree. | ✘ No (if or not) |
| Clause as sentence subject | Whether it works is another matter. | ✘ No (If it works is…) |
| After the question of, the issue of | the question of whether to sell | ✘ No |
| After ask, know, wonder, see | She asked whether we'd eaten. | ✔ Yes, informal |
| "Regardless" meaning | We'll go whether it's raining or not. | ✘ No |
Ambiguity with "if"
If can also introduce a condition, which sometimes creates ambiguity.
- Let me know if you're coming. = Tell me only in the case that you're coming (you might stay silent if you're not).
- Let me know whether you're coming. = Tell me either way.
In workplace emails, that difference matters. If you need a reply regardless, whether is clearer.
Where "whether" comes from
Whether goes back to Old English hwæther, which meant "which of two." That original sense explains why the word always involves alternatives. It is related to other wh- words such as which and what. Older English also used the phrase whether or no, which survives in some regional speech and older literature, but whether or not is the modern standard.
Pronunciation
Whether is pronounced WETH-er (with the th of this). Some speakers, particularly in parts of Scotland, Ireland and the American South, pronounce the wh with a breathy sound, roughly HWETH-er, which distinguishes it from weather. For most speakers in England, Australia and much of the US, whether and weather sound identical.
24 example sentences
Everyday
- We're going camping at Wilsons Promontory whether or not the forecast improves.
- I can't remember whether I locked the back door.
- Whether you like it or not, you're helping with the dishes.
- My mum asked whether we'd be home for Christmas.
- The dog gets a walk every morning, whether it's sunny or pouring.
- I'm not sure whether this milk is still fresh.
Workplace and email
- "Please confirm whether you can attend Thursday's workshop."
- "The deadline stands whether or not the client sends feedback."
- "We're still deciding whether to open a second office in Manchester."
- "Let me know whether the figures look right to you."
- "Whether or not the merger goes through, your role is secure."
- Our manager in Austin hasn't said whether the bonus will be paid this year.
Academic
- This study examines whether early reading programs improve later outcomes.
- Whether the treaty was ever enforced remains a matter of debate.
- Participants were asked whether they had used the service before.
- The model performs well whether or not the outliers are removed.
News style
- Officials have not confirmed whether the bridge will reopen before the long weekend.
- The concert in Hyde Park will go ahead whether or not the rain eases.
- Voters will decide whether to approve the new council tax rate.
- It is unclear whether the senator will run again.
Persuasive and personal
- Whether or not you've run before, the couch-to-5K program can help.
- The question is whether we act now or wait for the next crisis.
- Everyone deserves respect, whether they agree with you or not.
- You'll feel better tomorrow whether you believe it right now or not.
US vs UK vs Australia
The grammar of whether and whether or not is the same in the United States, the United Kingdom and Australia. The deletion test, the rules about whether vs if, and the comma conventions apply equally in all three.
A few small differences in habit are worth noting:
- United States: American style guides and editors often trim redundant or not in noun clauses. If is extremely common in informal indirect questions (I asked if she was ready).
- United Kingdom: British writing follows the same patterns. The older whether or no still occasionally appears in British fiction and regional speech, though most British writers now use whether or not.
- Australia: Australian usage matches British and American norms closely. You may also hear informal phrases such as "whether you like it or lump it" in casual speech across all three countries.
In short, you can follow one set of rules for all three audiences.
Common mistakes
❌ We're leaving at noon whether you're ready. ✅ We're leaving at noon whether or not you're ready.
❌ I'm not sure if or not the store is open. ✅ I'm not sure whether or not the store is open. ✅ I'm not sure whether the store is open.
❌ We talked about if we should sell the house. ✅ We talked about whether we should sell the house.
❌ She couldn't decide if to accept the offer. ✅ She couldn't decide whether to accept the offer.
❌ The game depends on the whether. ✅ The game depends on the weather.
❌ Whether or not the plan is approved or not, we'll proceed. ✅ Whether or not the plan is approved, we'll proceed.
❌ Please advise as to whether or not the invoice has been paid. ✅ Please let me know whether the invoice has been paid.
The last example isn't strictly wrong, but as to whether or not is wordy. In business writing, cutting it down makes the request crisper. For more ways to tighten email requests, see our list of other ways to say "please let me know".
Punctuation tips
- Introductory clause: Put a comma after a whether or not clause that begins a sentence: Whether or not you agree, the policy stands.
- Clause at the end: A comma is optional: The policy stands whether or not you agree. Use one if you want a slight pause or emphasis.
- Noun clause: Don't separate a noun clause from its verb with a comma: Whether the plan works depends on funding (no comma after works).
A memory trick
"No matter? Need the 'not.'"
If you can rephrase the sentence with no matter whether or regardless of whether, you need or not: "We'll go no matter whether it rains" → "We'll go whether or not it rains." If the clause is just reporting a question ("She asked ___"), the not is optional, and usually it can go.
For the spelling, remember: weather has "eat" in it; you might eat outside if the weather is nice. Whether has no eat; it's about choices.
Practice quiz
Decide whether or not is required, optional, or wrong, or choose the correct word.
- The parade will happen whether ______ it snows. (Fill in: or not needed?)
- Can you tell me whether ______ the train stops at Reading? (Is or not required?)
- We had a long discussion about ______ to renovate. (if / whether)
- ______ the experiment succeeds depends on the temperature. (If / Whether)
- Correct this sentence: "I'm going whether you come."
- The barbecue is cancelled because of the ______. (weather / whether)
Answers
- or not is required: the meaning is "regardless of whether."
- Optional, better omitted: it's an indirect question, so "whether the train stops" is complete.
- whether: only whether can follow a preposition (about).
- Whether: a clause acting as the subject of a sentence must start with whether.
- "I'm going whether or not you come." (or whether you come or not): the "regardless" meaning needs both alternatives.
- weather: the noun for rain, sun and wind.
Related grammar guides
Small words like whether cause outsized trouble because they do several jobs. If you enjoy pinning down these distinctions, try then vs than, who vs whom and i.e. vs e.g., each of which has a quick test you can carry in your head.
The editor's rule of thumb
Read your sentence without or not. If it still makes complete sense, the two words are optional, and cutting them usually makes your writing tighter. If the sentence suddenly sounds incomplete, you are using the "regardless" meaning, and or not has to stay, either right after whether or at the end of the clause.
Frequently asked questions
Is 'whether or not' redundant?
Sometimes. When whether introduces a question-like clause after verbs such as ask, know, decide or wonder, 'or not' is usually unnecessary: 'I wonder whether she'll call' is complete. But when the meaning is 'regardless of whether,' the 'or not' is required: 'We'll play whether or not it rains.'
Is it 'whether or not' or 'whether it rains or not'?
Both orders are correct. 'Whether or not it rains' keeps the two words together, which is clearer in long sentences. 'Whether it rains or not' sounds natural in short, conversational sentences. Choose the one that reads more smoothly.
Can I use 'if' instead of 'whether'?
Often, yes, especially in informal English after verbs like ask, know and wonder. But you cannot use if directly after a preposition, before an infinitive, immediately before 'or not,' or at the start of a sentence as the subject. In those positions, whether is required.
What is the difference between whether and weather?
Whether is a conjunction used to introduce alternatives ('whether you like it or not'). Weather is a noun for conditions in the atmosphere, such as rain and sunshine, and also a verb meaning to survive a difficulty ('weather the storm'). They sound the same in most accents but are unrelated words.
Is 'whether or no' correct?
Whether or no is an older form of whether or not. It still appears occasionally in British writing and in fiction, but it sounds dated or regional to most modern readers. In everyday writing, use whether or not.
Should there be a comma before 'whether or not'?
When a whether-or-not clause comes at the start of a sentence, follow it with a comma: 'Whether or not you agree, the policy starts Monday.' When it comes at the end, a comma is optional and often left out: 'The policy starts Monday whether or not you agree.'