Quick answer: “Know something like the back of your hand” means to know something extremely well.
Know something like the back of your hand means to know a place, subject, or thing extremely well, in great detail, through long familiarity.
Origin & History
The phrase suggests such deep familiarity that you could recognise the back of your own hand instantly, without needing to look closely — a natural comparison for effortless knowledge.
It is commonly used about places, routes, subjects, and skills that someone has known for a long time.
Idioms like this are the kind of expression documented in general reference works such as the Cambridge Dictionary, which record how figurative meanings develop in everyday English.
Example Sentences
| Sentence | Context |
|---|---|
| The taxi driver knows the city like the back of his hand. | Driving, local knowledge |
| After ten years here, I know this office like the back of my hand. | Work |
| She knows the recipe like the back of her hand. | Cooking, skill |
| He knows the rules of the game like the back of his hand. | Sport, games |
| The guide knows the trail like the back of her hand. | Travel, expertise |
How to Use It
The idiom is used with ‘know’ conjugated for tense and subject, followed by ‘like the back of’ plus the correct possessive: ‘my hand’, ‘his hand’, ‘her hand’.
Common Mistakes
Mistakes to Avoid
know like back of hand.
know like the back of your hand. — Both articles/possessives, ‘the’ and ‘your’, are needed.
know as the back of your hand.
know like the back of your hand. — The comparison word is ‘like’, not ‘as’.
know like the palm of your hand.
know like the back of your hand. — The fixed noun is ‘back’, not ‘palm’.
Similar Idioms
Practise This Idiom
Practice English Idioms
Use these exercises to master idioms in context:
Want to understand the grammar behind this? Explore our Grammar guides.
Quick Check: Know something like the back of your hand
2 questions — test what you just learned.
1. What does “Know something like the back of your hand” mean?
2. Complete the sentence: “The taxi driver knows the city _____.”
Frequently Asked Questions
What does "know something like the back of your hand" mean?
To know a place, subject, or thing extremely well, in great detail, through long familiarity.
Where does "know something like the back of your hand" come from?
The phrase suggests such deep familiarity that you could recognise the back of your own hand instantly, without needing to look closely — a natural comparison for effortless knowledge.
Can you give an example of "know something like the back of your hand" in a sentence?
"The taxi driver knows the city like the back of his hand." Another: "After ten years here, I know this office like the back of my hand."
Is "know something like the back of your hand" formal or informal?
It is informal to neutral, and common in everyday spoken and written English.
What CEFR level is "know something like the back of your hand"?
B2. It suits learners who are comfortable with figurative, idiomatic language at this level.
What are common mistakes with "know something like the back of your hand"?
A common mistake is saying “know like back of hand” instead of “know like the back of your hand”. Both articles/possessives, ‘the’ and ‘your’, are needed.
What idioms are similar to "know something like the back of your hand"?
Related expressions include Know the ropes, Know something inside out, Up to speed.
Can "know something like the back of your hand" be used in writing?
Yes, it appears in blogs, informal articles, and everyday written messages, though very formal writing may prefer a more direct wording.
How do I practise idioms like "know something like the back of your hand"?
Use LexFizz Flash Cards and Flip Tiles, and try using "know something like the back of your hand" in a sentence of your own to connect the idiom to a real situation.
Can this idiom be shortened in casual speech?
It's sometimes shortened informally to ‘know it like the back of my hand’, but the full comparison with ‘hand’ should stay in place.