Engineering Notation & SI Prefix Converter — Scientific, Engineering & k/M/µ/n Forms
Convert a number between plain decimal, scientific notation, engineering notation (exponent a multiple of 3) and SI-prefix form (1.5k, 4.7µ, 2.2M, 3.3n) — all shown at once, live in your browser. Type in any form, set the significant figures, and copy any representation.
How to Use
- Type a number in any form: plain (1500), scientific (2.2e6), engineering (47e3) or SI-prefix (4.7k, 3.3µ).
- Read off the plain decimal, scientific, engineering and SI-prefix forms — they all update instantly.
- Use the significant-figures control to round the mantissa to the precision you need.
- Click any value (or its Copy button) to copy it to the clipboard.
Four ways to write the same number
Every value here is shown in four equivalent forms at once. Plain decimal is the everyday way of writing a number out in full. Scientific notation writes it as a single non-zero digit, a decimal point, and a power of ten — 4.7×10⁴ — which is compact and great for very large or very small magnitudes. Engineering notation is the same idea but the exponent is forced to a multiple of three, so the mantissa runs from 1 to 999 and the powers line up with the metric system: 47×10³. SI-prefix form then replaces that power of ten with its letter — 47k, 4.7µ, 2.2M — the way component values and measurements are normally quoted. Type in any of the four and read off the others; nothing is uploaded.
How engineering notation and SI prefixes line up
The SI prefixes are names for powers of one thousand. Going up: kilo (k, 10³), mega (M, 10⁶), giga (G, 10⁹), tera (T, 10¹²), then peta, exa, zetta and yotta (Y, 10²⁴). Going down: milli (m, 10⁻³), micro (µ, 10⁻⁶), nano (n, 10⁻⁹), pico (p, 10⁻¹²), then femto, atto, zepto and yocto (y, 10⁻²⁴). Because each prefix is exactly three orders of magnitude apart, engineering notation — whose exponent is always a multiple of three — maps onto them one-to-one. To convert, find the multiple of three at or below the number's order of magnitude, shift the decimal point to suit, and swap in the matching prefix. Watch the case: lowercase m is milli (10⁻³) but uppercase M is mega (10⁶), and micro can be typed as µ or as a plain u.
Quick reference
About the Engineering Notation & SI Prefix Converter — Scientific, Engineering & k/M/µ/n Forms
Working on everyday tasks? The Engineering Notation & SI Prefix Converter — Scientific, Engineering & k/M/µ/n Forms is a free browser tool that gives you the answer in seconds. Convert a number between plain decimal, scientific notation, engineering notation (exponent a multiple of 3) and SI-prefix form (1.5k, 4.7µ, 2.2M, 3.3n) — all shown at once, live in your browser. Type in any form, set the significant figures, and copy any representation.
How it works
Type a value, then pick what you want to change it into. The answer appears straight away. It all happens on your own device, so it is fast and nothing you type is sent away. Just check that you picked the right “from” and “to” so you get the answer you wanted.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
What is the difference between scientific and engineering notation?
Both write a number as a mantissa times a power of ten. Scientific notation keeps exactly one non-zero digit to the left of the decimal point (so the exponent can be any integer): 47000 = 4.7×10⁴. Engineering notation restricts the exponent to a multiple of three so it lines up with the SI prefixes, which means the mantissa can be 1 to 999: 47000 = 47×10³. Engineering form is the one electronics and engineering use because 10³ is "kilo", 10⁻⁶ is "micro", and so on.
What are the SI (metric) prefixes?
They are names for powers of one thousand: kilo (k, 10³), mega (M, 10⁶), giga (G, 10⁹), tera (T, 10¹²) and on up to yotta (Y, 10²⁴) for big numbers; and milli (m, 10⁻³), micro (µ, 10⁻⁶), nano (n, 10⁻⁹), pico (p, 10⁻¹²) and down to yocto (y, 10⁻²⁴) for small ones. So 1.5 k = 1500 and 4.7 µ = 0.0000047.
How do I type micro?
Use the µ symbol or just the letter "u" — both are read as micro (10⁻⁶). For example "2.2u" and "2.2µ" both mean 0.0000022. Prefixes are case-sensitive everywhere else: "m" is milli (10⁻³) but "M" is mega (10⁶).
Why does engineering notation show 47×10³ instead of 4.7×10⁴?
Because the exponent must be a multiple of three. Shifting 4.7×10⁴ to the nearest lower multiple of three (10³) moves the decimal point one place right, giving 47×10³. The mantissa is then between 1 and 999, which maps directly onto the kilo prefix: 47×10³ = 47 k.
Is anything uploaded?
No. The whole conversion runs in your browser with JavaScript — nothing is sent to a server.
How do I use the Engineering Notation & SI Prefix Converter — Scientific, Engineering & k/M/µ/n Forms?
Just type or paste your value. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Do I need to install or sign up for anything?
Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.
Is my information private?
Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.
Common Use Cases
Electronics & circuit design
Read resistor, capacitor and frequency values in the engineering/SI form schematics use — 4.7 kΩ, 100 nF, 2.2 µF, 16 MHz.
Reading datasheets
Convert a quoted value like 1.5 µs or 3.3 mV into plain decimal or scientific notation to plug into a formula or spreadsheet.
Science & lab work
Move between scientific notation from a calculator and the SI-prefixed units used in reports and measurements.
Learning notation
See the same number side by side in scientific and engineering forms to understand why the exponent jumps in threes.
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