What is scientific notation?
Scientific notation is a short way to write very large or very small numbers. Instead of 299,792,458 (the speed of light in metres per second) you write 2.998 × 10⁸, and instead of 0.000045 you write 4.5 × 10⁻⁵. The number is split into a coefficient between 1 and 10 and a power of 10 that shows how many places the decimal point moved. Scientists, engineers and students use it to keep numbers readable and to compare their size at a glance.
How to use the converter
- Type a number in any form: normal (0.000045), E notation (6.022e23) or with "× 10^".
- Choose how many significant figures to keep, or "All" for full precision.
- Read the number in scientific, E, engineering and decimal form.
Converting by hand
Move the decimal point until only one non-zero digit is left of it. Count the moves: moving left gives a positive power, moving right gives a negative power.
299,792,458 → 2.99792458 (8 moves left) → 2.998 × 10⁸
0.000045 → 4.5 (5 moves right) → 4.5 × 10⁻⁵
The three notations
| Notation | Example | Where you see it |
|---|---|---|
| Scientific | 4.7 × 10⁴ | Textbooks, exams, science papers |
| E notation | 4.7E+4 | Calculators, Excel, programming |
| Engineering | 47 × 10³ | Electronics and engineering; the power is always a multiple of 3, matching prefixes like kilo (10³), mega (10⁶) and micro (10⁻⁶) |
Significant figures
Significant figures are the digits that carry meaning about precision. A measurement of 0.00450 m has 3 significant figures (4, 5 and the final 0). Scientific notation makes them obvious: 4.50 × 10⁻³. When you round to 3 significant figures, 299,792,458 becomes 3.00 × 10⁸.
Frequently asked questions
How do I multiply numbers in scientific notation?
Multiply the coefficients and add the powers: (2 × 10³) × (3 × 10⁴) = 6 × 10⁷.
What is the largest number supported?
About 1.8 × 10³⁰⁸, the largest number a web browser can store.
Why does Excel show 1.23E+11?
Excel switches to E notation when a number is too wide for the cell. Widen the column or change the number format.