Engineering notation is the form scientists and engineers reach for when they want numbers that map cleanly onto SI unit prefixes. This converter rewrites any value so its exponent is a multiple of three and tells you the matching prefix.
How it works
Ordinary scientific notation writes a number as a mantissa between 1 and 10 times a power of ten with any integer exponent. Engineering notation keeps the same idea but constrains the exponent to be a multiple of three. As a consequence, the mantissa can range anywhere from 1 up to just below 1000.
To convert, the tool first computes the standard base-10 exponent as the floor of the logarithm of the absolute value. It then rounds that exponent down to the nearest lower multiple of three to get the engineering exponent. Finally it divides the original number by ten raised to that engineering exponent to obtain the mantissa.
Worked example
Take 47000. Its base-10 exponent is 4 (since it is between 10⁴ and 10⁵). Rounding 4 down to the nearest multiple of three gives 3. Dividing 47000 by 10³ gives a mantissa of 47, so the engineering form is 47 × 10³. The exponent 3 corresponds to the SI prefix kilo, so 47000 hertz is naturally read as 47 kHz.
The SI prefix ladder
Engineering notation exists precisely because SI prefixes step in multiples of one thousand. Here are the most commonly encountered prefixes alongside their engineering exponent:
| Prefix | Symbol | Exponent | Example |
|---|---|---|---|
| tera | T | 10¹² | 2.4 THz |
| giga | G | 10⁹ | 3.5 GHz |
| mega | M | 10⁶ | 100 MHz |
| kilo | k | 10³ | 4.7 kΩ |
| — | — | 10⁰ | 1 Ω |
| milli | m | 10⁻³ | 47 mA |
| micro | µ | 10⁻⁶ | 2.2 µF |
| nano | n | 10⁻⁹ | 100 nH |
| pico | p | 10⁻¹² | 10 pF |
The converter covers the full ladder from yocto (10⁻²⁴) to yotta (10²⁴).
Where engineering notation is used in practice
- Electronics. Component values are always expressed in engineering notation. A resistor data sheet lists 4.7 kΩ rather than 4700 Ω; a capacitor is 2.2 µF rather than 0.0000022 F. This convention makes reading a schematic or a bill of materials much faster.
- Signal frequencies. Radio frequencies run from a few kHz (AM broadcasts) through MHz (FM, Wi-Fi) to GHz (5G, microwave ovens). Engineering notation keeps the numbers in a comfortable 1–999 range.
- Power and energy. A solar panel might produce 350 W; a national grid operates in gigawatts. Engineering notation matches these to kW, MW, or GW without ambiguity.
- Data storage and transfer. Gigabytes and megabits-per-second are engineering notation applied to information quantities.
Tips
The converter accepts scientific input like 1.2e9 or 3.3e-6 directly, so you can paste values from datasheets or code without pre-converting. Negative numbers are handled correctly — the sign is preserved and only the magnitude is used to find the engineering exponent. All processing runs locally in your browser.