# Scientific Notation Converter - Standard Form, E Notation and Engineering

> Free online scientific notation converter: switch between plain numbers and a×10ⁿ, accept 3.5e6, and get engineering notation with SI prefixes and rounding.

- URL: https://qilingtools.com/en/math/scientific-notation
- Category: Math Tools (https://qilingtools.com/en/math)
- Tags: [Math](https://qilingtools.com/en/tags/math), [Education](https://qilingtools.com/en/tags/education)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

Turn very large or very small numbers into a×10ⁿ, or expand scientific notation back into a plain number. You also get engineering notation (exponent a multiple of 3, with k/M/G prefixes), the value rounded to your chosen significant figures, and how many significant figures the input has.

## How to use

1. Type a plain number (3500000) or scientific notation (3.5e6, 3.5×10^6)
2. Choose how many significant figures to keep
3. Read the scientific, plain and engineering forms

## Features

- Two-way conversion between plain numbers and scientific notation
- Accepts both e notation and ×10^ input
- Engineering notation labelled with SI prefixes (k / M / G / m / µ)
- Rounding to a chosen number of significant figures
- Counts the significant figures in the input

## FAQ

### How is scientific notation written?

As a×10ⁿ with 1 ≤ |a| < 10 — for example 3500000 = 3.5×10⁶ and 0.00042 = 4.2×10⁻⁴.

### What does 1e6 mean?

1×10⁶ = 1000000. Type 1e6 into the box to see the plain form.

### How does engineering notation differ?

Its exponent is always a multiple of 3, so 35000 becomes 35×10³, lining up with prefixes such as k (kilo) and M (mega).

### How do I count significant figures?

Start at the first non-zero digit; trailing zeros in a whole number do not count, but trailing zeros after a decimal point do. The tool reports the count for your input.

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