Future Time Clauses: When, Before, After, Until and More

Hello English learners, and welcome to a new lesson! Today, you’ll learn how future time clauses work, which expressions introduce them and how to avoid one of the most common mistakes English learners make.

Which sentence is correct?

I’ll call you when I arrive.
I’ll call you when I will arrive.

The first one is correct.

This is because English has a special rule for talking about the future after words such as when, before, after, until and as soon as.

Although we are talking about the future, we normally use a present tense in the time clause, not will.

Table of Contents

What Are Future Time Clauses?

A future time clause tells us when a future action will happen.

These clauses commonly begin with:

when, while, before, after, until, as soon as, once, by the time, the moment

Look at this example:

I’ll call you when I get home.

There are two parts:

Main clause:

I’ll call you.

Time clause:

when I get home

Although getting home refers to the future, we use the present simple:

✔ when I get home

✘ ~~when I will get home~~

A useful basic pattern is:

future form + time word + present tense

I’ll tell you when I know.
We’ll leave after the meeting finishes.
She’ll stay here until the rain stops.

The time clause can also come first:

When I know, I’ll tell you.
After the meeting finishes, we’ll leave.

Notice the comma when the time clause comes at the beginning.

Future Time Clauses with WHEN

We use when to talk about something that we expect to happen at a particular time in the future.

I’ll make dinner when I get home.
When I finish work, I’ll give you a call.

Remember:

✔ I’ll phone you when I arrive.

✘ ~~I’ll phone you when I will arrive.~~

Future Time Clauses with WHILE

We use while when two actions or situations happen during the same period of time.

While I’m on holiday, my neighbour will water my plants.
I’ll prepare dinner while you set the table.

Because while often refers to an action already in progress, we frequently use the present continuous:

I’ll call you while I’m travelling home.
She’ll look after the children while we’re having dinner.

Future Time Clauses with BEFORE

We use before when one future event will happen earlier than another.

Katie will finish her homework before she goes to bed.
I’ll call you before I leave the office.

Again, there is no will after before:

✔ I’ll speak to her before she leaves.

✘ ~~I’ll speak to her before she will leave.~~

Future Time Clauses with AFTER

We use after when one action happens later than another.

Jill will call you after she finishes her meeting.
After the guests leave, we’ll tidy up.

We can also use the present perfect when we want to emphasise that the first action will be completed before the second begins:

I’ll call you after I’ve spoken to David.

Compare:

I’ll call you after I finish work.
I’ll call you after I’ve finished work.

Both are correct. The present perfect gives slightly more emphasis to the completion of the first action.

Future Time Clauses with UNTIL

We use until to show that an action or situation continues up to a particular point in the future.

We’ll wait here until the rain stops.
I’ll keep practising until I feel more confident.

Be careful with negative sentences.

Compare:

I’ll stay here until you come back.
I won’t leave until you come back.

Both mean that I will remain here up to the moment you return.

Future Time Clauses with AS SOON AS

We use as soon as when one action will happen immediately after another.

I’ll call you as soon as I arrive at the hotel.
As soon as I hear anything, I’ll tell you.

Think of as soon as as meaning:

immediately when

Future Time Clauses with ONCE

Once means when something has happened or been completed.

Once you finish the form, send it to me.
We’ll make a decision once we have all the information.

We often use once when the second action depends on the first one being completed.

Future Time Clauses with BY THE TIME

We use by the time to talk about something that will already have happened before another future point.

By the time you arrive, dinner will be ready.
She’ll have finished the report by the time the manager returns.

Notice something interesting here:

The main clause can contain the future perfect, but the clause after by the time still uses a present tense.

✔ By the time you arrive, I’ll have finished.

✘ ~~By the time you will arrive, I’ll have finished.~~

Future Time Clauses with THE MOMENT

The moment means as soon as and is particularly common in spoken English.

I’ll let you know the moment I hear anything.
The moment she arrives, we’ll start.

We can also use:

the minute

the second

I’ll phone you the minute I know.
The second he walks through that door, tell me.

These expressions add a sense of immediacy.

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Do We Always Use the Present Simple?

The present simple is the most common tense in future time clauses.

However, other present forms are possible.

Present continuous

Use it when an action will be in progress:

I’ll text you while I’m waiting for the train.

Present perfect

Use it when you want to emphasise completion:

We’ll go out after I’ve finished this email.
Call me when you’ve spoken to Sarah.

So the broader rule is:

After a future time expression, we normally use a present tense rather than a future tense.

Download the Future Time Clauses – Practice Worksheet in PDF here

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