Common mistakes
When or if: choosing the condition word
A friend says, "When I see Nora, I'll give her your message." The speaker expects to see Nora. Change when to if, and the sentence means that seeing Nora is uncertain.
Choose when for an expected time and if for a condition that may or may not happen.
Read and practice
Read the examples and try the written questions in this guide. Listening recordings are not available for this lesson yet.
Try the written questions
when / if /wen/ /ɪf/
The short answer
Use when when you expect the event to happen. Use if when you mean "only in the case that" or when the event is uncertain.
When the meeting ends, I'll send you the notes. If the meeting ends early, I'll call you.
Why it works: The meeting is expected to end. Ending early is only a possibility.
3 more examples
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When I finish work, I'll pick up the parcel.
The speaker treats finishing work as the expected time for the next action.
Not this:
If I finish work early, I'll pick up the parcel. What changes: Finishing early is not certain, so it is the condition for picking up the parcel. -
When the weather gets cold, the lake freezes.
This is a regular or general result. When describes the usual time or situation.
Not this:
If the weather gets cold enough tonight, the lake may freeze. What changes: Tonight's temperature is uncertain, so the sentence uses if. -
Call me when you arrive at the station.
The speaker expects the other person to arrive and asks for a call at that time.
Not this:Call me
if you arrive before six. What changes: Arrival before six is the condition for making the call.
Read the full guide
First ask one question: am I naming an expected time, or am I setting a condition? That choice usually gives you the right word.
Decide whether the event is expected
Use when if you see the event as part of the plan or routine. It tells the listener when the next action will happen.
When the train arrives, we'll get on.
The train is expected to arrive. The sentence does not question that fact.
Use if for a real condition
Use if when one fact needs to be true before another action can happen. The condition may happen, but it is not guaranteed.
If the train is delayed, we'll take a taxi.
Taking a taxi depends on a delay. The speaker does not know whether there will be one.
Keep will in the result clause
After when or if, use a present form to talk about the future. Put will in the main result clause when you need it.
Correct: When she gets home, she will text us. Incorrect: When she will get home, she will text us.
If it rains tomorrow, we will stay inside.
Notice general truths and routines
For things that happen regularly, when often means every time that. If can also work when you want to focus on the condition itself.
When I drink coffee late, I cannot sleep.
If you press this button, the screen turns on. The sentence gives an instruction and its result.
Make the meaning clear in a plan
You know that Maya is coming to the office tomorrow. You want to say that you will speak to her at that time. Which word fits?
Use when: "When Maya comes to the office tomorrow, I'll speak to her." Her visit is expected. Use if only if you are unsure that she will come.
Before you go
Remember this
Use when for an expected time or a repeated result. Use if for a condition that may not happen. In future clauses with either word, use the present simple: "when it arrives" or "if it arrives," not "when it will arrive."
Practice with the written examples
You can practice with the written questions in the Learn tab. Each answer includes an explanation.
Try the written questionsListening test not available yet
This lesson does not have the recordings needed for a listening test. Use the written questions in the guide to check your understanding.
Try the written questionsQuestions about "When or if: choosing the condition word"
What is the main difference between when and if?
Use when for an event you expect to happen or for a regular event. Use if when the event is a condition and may not happen.
When I finish work, I'll pick up the parcel.
Can I use when and if with the future?
Yes. In a future clause after when or if, use the present simple: "when she arrives" or "if she arrives." Put will in the main result clause if needed.
If I finish work early, I'll pick up the parcel.
Why is "when it will rain" usually wrong?
After when in a future time clause, English normally uses the present simple. Say "when it rains" rather than "when it will rain."
When the weather gets cold, the lake freezes.
Can when and if both describe general truths?
Sometimes. "When you heat ice, it melts" describes a regular result. "If you heat ice, it melts" gives more attention to the condition.
If the weather gets cold enough tonight, the lake may freeze.
Which word should I use for an appointment?
Use when if the appointment is arranged and expected: "When I see the doctor, I'll ask about the medicine." Use if when the appointment itself is uncertain.
Call me when you arrive at the station.
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