Exact conversion, no rounding
Instead of using floating-point maths, the converter reads your digits as text and moves the decimal point. That keeps every digit you typed, so 123456789012345678901 converts exactly. It then builds scientific, E and engineering notation, a full decimal expansion and a significant figures count.
Where it helps
Use it for physics and chemistry homework (Avogadro's number 6.02 × 10²³), for reading spreadsheet E values, or to match SI prefixes with engineering notation. For other number work, try the fraction calculator, the number base converter or number to words.
Frequently asked questions
What is scientific notation?
It writes a number as a × 10ⁿ where a is at least 1 and less than 10. For example 123,456 = 1.23456 × 10⁵ and 0.00045 = 4.5 × 10⁻⁴. It makes very big and very small numbers easy to read.
What is E-notation?
E-notation is the same idea typed on calculators and in code: 1.23456E+5 means 1.23456 × 10⁵. Spreadsheets and programming languages use it for large and small values.
What is engineering notation?
Engineering notation keeps the exponent a multiple of 3 (like 10³, 10⁶, 10⁻⁹), so it lines up with units such as kilo, mega and nano. 123,456 becomes 123.456 × 10³.
How do I count significant figures?
All non-zero digits count, zeros between them count, and trailing zeros count only if the number has a decimal point. 1200 has 2 (or more if written 1200.), while 1.200 has 4. Leading zeros never count.
What can I type?
Plain numbers (123456, 0.00045), E-notation (1.2e5, 6.02E23) or the written form (3.4 x 10^-5, 6.02×10^23). Digits are handled as text, so even very long numbers are converted exactly.