# Scientific Notation Converter

> Scientific notation converter: turn decimals into scientific or engineering notation and back, with adjustable significant figures. Free, runs in your browser.

- **Canonical URL:** https://boringtoolskit.com/scientific-notation-converter/
- **Category:** Converters
- **Evidence level:** authored-methodology
- **Reviewed:** 2026-09-20
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Scientific notation = mantissa x 10^exponent, with the mantissa normalised to 1 <= |mantissa| < 10. Engineering notation uses the same mantissa but rounds the exponent down to a multiple of 3, so 1.23e-5 and 12.3e-6 are equivalent.

## Assumptions

- Inputs are treated as exact decimal values.
- Standard (not historical or survey) unit definitions are used.
- The calculation uses the factors at the precision shown in the formula panel; rounding beyond that is display-only and adds no accuracy.

## Common questions

### What does the significant-figures setting change?

It sets how many digits are kept in the mantissa. The value itself is unchanged - this only controls how precisely the same number is written, not its accuracy.

## Sources

- [SI Brochure, scientific notation conventions](https://www.bipm.org/en/publications/si-brochure)

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