Mathematics
What is Infinity?
Infinity is the idea of something without any end or limit — larger than any number you could ever count to. It's not a number itself but a concept, and mathematicians have shown there are even different 'sizes' of infinity.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains infinity.
Key things to understand
- 1It describes something endless, beyond any finite number.
- 2It's a concept, not a number you can do ordinary arithmetic with.
- 3The counting numbers go on forever — one example of infinity.
- 4Surprisingly, some infinities are 'bigger' than others.
- 5It appears across math, from calculus to set theory.
Frequently asked questions
- Is infinity a number?
- No — it's a concept describing something without end. You can't treat it like an ordinary number in arithmetic.
- Can one infinity be bigger than another?
- Yes — mathematician Georg Cantor showed the infinity of all decimals is larger than the infinity of counting numbers.
- What does infinity look like in math?
- It shows up as endless sequences, limits in calculus, and the symbol ∞, representing values that grow without bound.