Scientific & Engineering Notation Calculator

Enter a number in decimal or E-notation (e.g., 1.23e-5 or 1.23×10^−5). Choose significant figures if you want rounding. Everything runs in your browser.

What this calculator does

Scientific notation takes a number and writes it as a × 10ⁿ where 1 ≤ |a| < 10. It keeps the important digits visible and moves the decimal point by powers of ten. Engineering notation uses the same idea but snaps the exponent to multiples of three (…−9, −6, −3, 0, 3, 6…), which lines up with SI prefixes like milli, kilo, and mega. This page converts both ways, shows E-notation, and gives you an approximate full decimal view so you can sanity-check the size.

It also does quick math. Drop in two values—anything from 6.022e23 to 1.2×10^−5—pick an operation, and you’ll get a normalized result with the same significant-figure control used everywhere else. If you’re comparing units or scaling results, pair this tool with the Unit Converter. For fraction cleanup before converting, the Fraction Ratio Calculator can help.

Convert a number

Rounding is to chosen significant figures.

How to use this calculator

  1. Paste any number format. Decimal, E-notation (1.2e-5), or “×10^n” style (4.7×10^3) are all accepted.
  2. Pick your mode. Scientific keeps the mantissa between 1 and 10. Engineering snaps exponents to multiples of 3 to align with SI prefixes.
  3. Set significant figures. Default is 6. Move up or down to match lab conventions or textbook rounding.
  4. Choose separators. Toggle grouped digits for readability when inspecting the decimal approximation.
  5. Use Quick math. Enter A and B, choose an operation, and you’ll get a rounded, normalized output with the steps listed.
  6. Export CSV. Save inputs/outputs to paste into lab notebooks or homework docs. If you’re juggling units, the Unit Converter pairs well.

Reading the results

Scientific vs engineering. Both are the same value—just formatted differently. Scientific notation is compact. Engineering notation is friendlier with real-world prefixes (kilo, mega, micro).

Mantissa and exponent. The mantissa carries your significant figures; the exponent shows the order of magnitude. A difference of 3 in the exponent is a thousand-fold change.

E-notation. Computers write a e n (e.g., 1.23e-5). It’s lightweight and copy-pasteable.

Full decimal (approx). Extremely large/small numbers are abbreviated to avoid unreadable strings. If you need exact rational forms first, clean up with the Fraction Ratio Calculator.

Rounding note: JavaScript numbers are IEEE-754 doubles—about 15–16 significant digits. This tool rounds to your selected figures, then normalizes the mantissa.

FAQ

Why does my decimal look slightly different after rounding?

Rounding to significant figures adjusts the mantissa, which can shift trailing digits in the decimal approximation. The exponent stays consistent with the chosen format.

What’s the difference between 1.2e3 and 1.2×10^3?

Nothing—just different notation. E-notation is keyboard-friendly; “×10^n” is typeset-friendly.

Can I enter negative numbers?

Yes. The sign is preserved and applied to the mantissa. The exponent rules are unchanged.

Why don’t you show the entire decimal for very large exponents?

To keep the page fast and readable. We cap the “full decimal” rendering for extreme magnitudes and show an explanatory note instead.