What is an octillion?

An octillion is the number 1,000,000,000,000,000,000,000,000,000 — a one followed by twenty-seven zeros. It equals one thousand septillions. Octillion-scale values appear in extreme physics calculations, such as the estimated number of atoms in the Earth (approximately 1.33 × 10⁵⁰, which involves octillion-range intermediate results) and in combinatorial mathematics where possibility spaces grow astronomically large.

Twenty-seven zeros are far beyond casual counting. Expanding or condensing numbers at this scale requires automated decimal shifting to ensure every zero is accounted for.

Tool description

This tool converts numbers expressed in octillions to their full numeric form and vice versa. Enter a value in the "Octillions" field to see it expanded with all twenty-seven zeros, or type a very large number in the "Full Number" field to determine how many octillions it represents. The conversion works both ways and updates in real time.

Examples

Octillions Full Number
1 1000000000000000000000000000
3 3000000000000000000000000000
0.5 500000000000000000000000000
1.5 1500000000000000000000000000
0.001 1000000000000000000000000

Features

  • Instant bidirectional conversion between octillions and full numbers
  • String-based math ensures perfect accuracy with 27+ digit numbers
  • Handles decimal values without floating-point precision issues
  • Runs entirely in the browser with no external dependencies
  • One-click swap to reverse the conversion direction

Use cases

  • Working with extreme-scale physics estimates in academic research
  • Expanding combinatorial results in advanced mathematics
  • Converting shorthand notation in cosmological or quantum-scale documents
  • Septillion Number Converter — for numbers with 24 zeros
  • Nonillion Number Converter — for numbers with 30 zeros