A clear explanation of the difference between "know" and "understand," including examples, usage rules, and common mistakes.
Two important verbs in English are know and understand. Both involve having information, but they are different:
- Know means having information or being aware of a fact.
- Understand means fully grasping the meaning or how something works.
Knowing is about having information.
Understanding is about making sense of it.
Know: I know the answer. (I have the answer.)
Understand: I understand the answer. (I see why it is the answer.)
Know
Use know when you have information, are familiar with something, or have a fact in your memory.
- I know her name.
- Do you know the capital of France?
- He knows how to swim.
Understand
Use understand when you grasp the meaning, reasons, or concepts behind something.
- I understand the problem now.
- She doesn’t understand the instructions.
- We need to understand why it happened.
Summary
| Situation | Use |
|---|---|
| Having information or being aware | know |
| Grasping meaning or concepts | understand |
Mistake 1: “I understand her name.”
Correction: I know her name.
Explanation: Names are facts to be known, not understood.
Why is 'I understand her name' incorrect?
Because a name is a fact to be known, not something you comprehend.
‘Know’ is used for facts like names, while ‘understand’ is for comprehension.
Mistake 2: “Do you know why 2+2=4?”
Correction: Do you understand why 2+2=4?
Explanation: The question asks for comprehension, not just knowing the fact.
Mistake 3: “I know how to solve this problem.”
(This can be correct, but if you mean you grasp the method, understand is better.)
Better: I understand how to solve this problem.
When is it better to say 'I understand how to solve this problem' instead of 'I know how to solve this problem'?
When you want to express that you grasp the method or reasoning, not just that you have the information.
'Understand' implies comprehension of the process, while 'know' may simply mean having the information.
- Know = have information or be aware.
- Understand = grasp meaning or make sense of something.
They are both correct verbs but used in different situations.
Knowing is about having information.
Understanding is about comprehending it.
Last updated: Thu Jun 12, 2025
