∞ Big Number Calculator
Ordinary calculators silently round anything past about 15 digits. This one uses true big-integer arithmetic, so a 40-digit addition or a 25-digit multiplication comes out digit-perfect, every time.
Just type whole numbers — as long as you like — pick add, subtract or multiply, and read the exact result plus its digit count.
How to use this calculator
Type two whole numbers of any length, pick add, subtract or multiply, and press Calculate for the exact result.
- Type the first big integer, as many digits as you like.
- Choose Add, Subtract or Multiply.
- Type the second big integer.
- Press Calculate and read the exact result and its digit count.
Frequently asked questions
What does this big number calculator compute?
It adds, subtracts and multiplies integers of unlimited size with exact precision using BigInt arithmetic, so no digits are ever rounded away the way ordinary calculators round past 15 digits.
Can you show a worked example?
123456789123456789123456789 plus 987654321987654321987654321 equals exactly 1111111111111111111111111110, all 28 digits correct.
Can I use decimals?
No. This tool handles whole integers only, because exactness is its whole point. For decimal arithmetic use the standard calculator pages instead.
Is there a size limit?
Practically none. You can enter hundreds of digits and the result stays exact, though extremely long inputs may take a moment to process.