Big Number Calculator – Calculate Large Numbers Online
Add and multiply arbitrarily large integers exactly, digit by digit.
About the Big Number Calculator
What is the Big Number Calculator?
A big number calculator adds, subtracts and multiplies integers of any length exactly, using string arithmetic instead of floating point.
Why use this calculator?
JavaScript numbers lose precision above 2^53. Scientific and digital-currency needs routinely exceed that, which is exactly where this shines.
How to use it
- Enter two integers (signs allowed).
- Choose +, − or ×.
- Read the exact result and digit count.
Formula
Column arithmetic implemented as string operations.
The largest exact floating-point integer is 9,007,199,254,740,991; beyond that this tool is needed.
Frequently Asked Questions
Why not just use a normal calculator?
Beyond ~16 digits, floats round numbers. String arithmetic keeps every digit.
How big can the numbers be?
Practically unlimited — the result is only limited by memory and the 200-digit display cap.
What order of operations does this use?
It follows standard PEMDAS/BODMAS rules: parentheses, exponents, multiplication and division, then addition and subtraction.
How precise are the answers?
The calculator uses double-precision floating-point math (about 15 significant digits) and rounds the display. For exact symbolic results use dedicated algebra software.
Can I enter negative numbers or decimals?
Yes. Negative values, decimals and very large or small numbers are all supported unless a field says otherwise.
What does it mean if I get an error?
Errors usually mean an invalid input, such as division by zero or a negative value where only positives make sense. Check your entries and try again.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.
How accurate are the results?
We use standard, widely accepted formulas and calculate in your browser using double-precision arithmetic. Results are rounded for readability, so treat them as reliable estimates rather than a guarantee. Real-world factors can vary the true figure.
Can I add this calculator to my own website?
Yes. Open this calculator page and use the "Add to your website" box in the sidebar to copy a ready-made iframe snippet, then paste it into any HTML page.
Does it work on a phone or tablet?
Yes. The layout is fully responsive, so it works on desktops, laptops, tablets and mobile phones, and every input adapts to touch screens.