What is engineering notation?

Engineering notation is like scientific notation but restricts the exponent to multiples of 3 (0, 3, 6, 9, 12, -3, -6, etc.), aligning with SI unit prefixes like kilo (10³), mega (10⁶), giga (10⁹), milli (10⁻³), micro (10⁻⁶). This makes it convenient for engineering calculations where SI prefixes are used.

What are significant figures?

Significant figures (sig figs) are the meaningful digits in a number that carry measurement precision. In 4.20 × 10³, there are 3 significant figures. Leading zeros are not significant; trailing zeros after a decimal point are significant. Scientific notation makes sig fig counting unambiguous.

E notation is a computer-friendly way to write scientific notation using the letter E instead of '× 10^'. For example, 4.2E4 means 4.2 × 10⁴ and 5.6E-4 means 5.6 × 10⁻⁴. E notation is used in most programming languages, spreadsheets, and calculators.

How do I convert scientific notation back to a standard number?

Move the decimal point right by the exponent for positive powers, or left for negative powers. 4.2 × 10⁴: move decimal 4 places right → 42000. 5.6 × 10⁻³: move decimal 3 places left → 0.0056. This tool handles the conversion automatically in both directions.

Scientific Notation Converter

Convert between standard numbers and scientific / engineering notation. Significant figures control, E notation, and batch conversion. 100% client-side.

Significant Figures: 2

Standard —

Scientific Notation —

E Notation —

Engineering Notation —

SI Prefix —

LaTeX —

Enter any number above to convert to scientific notation.

How to Use the Scientific Notation Converter

Enter a number in any format — standard (42000), E notation (4.2e4), or already in scientific notation (4.2 × 10⁴).
Adjust significant figures with the slider (1–10 sig figs).
View all formats — standard, scientific, E notation, engineering, SI prefix, and LaTeX.
Copy any result with the inline Copy buttons on each row.
Batch mode — enter multiple numbers, one per line, and download the full conversion table as CSV.

What is Scientific Notation?

Scientific notation is a way to express any real number as a coefficient multiplied by a power of ten. The coefficient is always a number between 1 (inclusive) and 10 (exclusive). For example, the speed of light (299,792,458 m/s) is written as 2.998 × 10⁸ m/s. The number of atoms in a mole (6.022 × 10²³) would be nearly impossible to work with in standard notation. Scientific notation makes arithmetic with very large or very small numbers tractable.

Scientific vs Engineering Notation

Engineering notation is a variant of scientific notation where the exponent is always a multiple of 3. This aligns with the metric SI prefixes: 10³ (kilo), 10⁶ (mega), 10⁹ (giga), 10¹² (tera), 10⁻³ (milli), 10⁻⁶ (micro), 10⁻⁹ (nano), 10⁻¹² (pico). Engineers prefer this form because measurements can be directly expressed with SI prefix units: 42,000 Hz becomes 42 × 10³ Hz = 42 kHz rather than 4.2 × 10⁴ Hz which doesn't map directly to a unit prefix.

Understanding Significant Figures

Significant figures convey measurement precision. When you write 4.2 × 10⁴, you're saying the value is known to 2 significant figures — the actual value is somewhere between 41,500 and 42,500. Writing 4.20 × 10⁴ (3 sig figs) means the value is between 41,950 and 42,050. Scientific notation is the clearest way to express sig figs because trailing zeros are unambiguous: 4.200 × 10⁴ clearly has 4 sig figs, while "42000" is ambiguous about whether those trailing zeros are significant.

E Notation in Programming

Most programming languages use E notation for scientific numbers: 4.2e4 means 4.2 × 10⁴. Python, JavaScript, Java, C, C++, Go, Rust, and virtually every other language accept this syntax in numeric literals and printf-style formatting. JavaScript's Number.toExponential() method outputs E notation; toPrecision() applies significant figures. In spreadsheets (Excel, Google Sheets), E notation is used when numbers are too large for the cell width.

Common Scientific Constants in Notation

Speed of light: 2.998 × 10⁸ m/s
Avogadro's number: 6.022 × 10²³ mol⁻¹
Planck's constant: 6.626 × 10⁻³⁴ J·s
Electron charge: 1.602 × 10⁻¹⁹ C
Gravitational constant: 6.674 × 10⁻¹¹ N·m²/kg²
Boltzmann constant: 1.381 × 10⁻²³ J/K
Distance to sun: 1.496 × 10¹¹ m
Mass of electron: 9.109 × 10⁻³¹ kg

Frequently Asked Questions

Scientific notation expresses any number as a coefficient between 1 and 10 multiplied by a power of 10. For example, 42000 = 4.2 × 10⁴ and 0.00056 = 5.6 × 10⁻⁴. It makes very large and very small numbers easy to write, compare, and calculate with.

Engineering notation is like scientific notation but restricts exponents to multiples of 3 (0, ±3, ±6, ±9, ...), matching SI unit prefixes like kilo (10³), mega (10⁶), milli (10⁻³), micro (10⁻⁶). So 42000 Hz = 42 × 10³ Hz = 42 kHz in engineering notation.

Significant figures are the meaningful precision digits in a number. 4.2 × 10⁴ has 2 sig figs; 4.20 × 10⁴ has 3. Scientific notation makes sig figs unambiguous — trailing zeros after the decimal are always significant.

E notation uses the letter 'E' instead of '× 10^'. So 4.2E4 = 4.2 × 10⁴ and 5.6E-4 = 5.6 × 10⁻⁴. It's the format used in programming languages, spreadsheets, and calculators because it only uses ASCII characters.

Move the decimal point right by the exponent for positive powers, left for negative. 4.2 × 10⁴ → move right 4 places → 42000. 5.6 × 10⁻³ → move left 3 places → 0.0056. This tool converts automatically in both directions.