Ago counts back from now. Before counts back from another moment in the past, or it can stand alone to mean "at an earlier time".
- Ago: We moved here three years ago. The counting starts today.
- Before: She had left before Mum arrived. The counting starts at another past moment.
- Before can also stand alone: I have met her before.
Ago: counting back from now
Ago always comes after a time: two days ago, a week ago, long ago. The counting starts from the moment you are speaking, so the verb is usually in the simple past.
Our family moved here three years ago.
Mia called an hour ago.
The dinosaurs lived a very long time ago.
I saw that film two weeks ago.
Before: counting back from another moment
Before counts back from a point in the past, not from now. It often goes with the past perfect (had left, had finished).
Leo had finished his drawing before the bell rang.
The train had left before we reached the station.
Sam woke up before the alarm rang.
Before can also come at the end of a sentence with no time after it. It then means "at any time earlier".
Have we met before?
I have never seen a purple cow before.
Have you been here before?
Before can also start a time or a clause: before dinner, before we left.
Easy way to tell them apart
Ask: am I counting back from today?
- Yes, from today? Use ago, after the time. (two days ago)
- No, from another moment in the past? Use before. (two days before the party)
I visited Rome two years ago. (counting from now)
I visited Rome two days before the party. (counting from the party)
💡 The OddLingo Trick
Ago sounds like "a-go": a time that has gone. And it always has its time right in front of it: a week ago, never just ago.
Before needs an anchor. If you cannot say "before what?", it is probably ago.
⚠️ Common Mistakes
Ago needs a time in front of it.
❌ We moved here ago.
✅ We moved here three years ago.
Do not use ago with the present perfect.
❌ I have lived here three years ago.
✅ I moved here three years ago.
Do not use before to count from today.
❌ I started school ten years before.
✅ I started school ten years ago.
📌 Good to know
- Ago is only for the past. For the future, say in three days.
- Since and for are close cousins. See since vs for.
💬 In a conversation
Sam: When did you get your cat?
Mia: Two months ago.
Sam: Did you have a pet before?
Mia: A goldfish named Gary. He wanted to be a dog.