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

Enter a decimal such as 0.00042, or a scientific value such as 4.2e-4. The results update as you type. Choose Scientific, Engineering, Standard or E-notation for the large display, then use the corresponding Copy button. All four forms also appear in the output cards.

What is the difference between scientific and engineering notation?

For a nonzero value, scientific notation gives the mantissa a magnitude from 1 up to, but not including, 10. Engineering notation uses an exponent divisible by three. For example, 0.00042 becomes 4.2 × 10⁻⁴ or 420 × 10⁻⁶. The latter has the micro prefix.

Why do trailing zeros change the significant figures?

They record the precision stated by the written number. 1.200 × 10³ has four significant figures; 1.2 × 10³ has two. Both equal 1200. The converter keeps this distinction in scientific notation and warns when another form cannot express it unambiguously.

How many significant figures does 1200 have?

This tool reads 1200 as two significant figures by convention: trailing zeros without a decimal point are placeholders. Write 1200. or 1.200 × 10³ to state four. The result flags the ambiguity; it does not determine how accurately the original quantity was measured.

Can it handle very large or very small exponents?

Yes, within the exponent limit of -999,999,999 to 999,999,999 after normalisation. For example, 1e1000 keeps its exact scientific form and expands to a 1 followed by 1,000 zeros. Standard form is omitted when it would exceed 10,000 characters; the other forms remain available.

What input formats are accepted?

Use ordinary decimals, e or E notation, or powers of ten such as 4.2 × 10^-4 and 4.2 x 10^-4. Unicode superscripts also work. A value such as 42 × 10⁻⁵ is normalised to 4.2 × 10⁻⁴. Fractions, binary notation, arithmetic expressions and attached units are not accepted.

Does it round to three significant figures?

No. It counts and preserves the significant figures in your input rather than rounding to a chosen count. Enter 1.23e4 if you already want to represent that value with three significant figures; entering 1.234e4 keeps four.

Does the SI prefix result convert physical units?

No. It names the prefix matching the engineering exponent, from quecto through quetta when one exists. For 0.00042, it shows 420 micro (µ). It does not accept unit labels or convert between metres, feet, kilograms or other units.

What is the order of magnitude?

Here it is the exponent in normalised scientific notation, using the absolute value for negatives. Zero has no order of magnitude. Exponents 6 and 3 differ by three powers of ten; the actual ratio also depends on the two mantissas, so it is exactly 1,000 only when those mantissas match.

Scientific Notation Converter

Convert a number between standard, scientific, engineering and E notation. See its significant-figure count, order of magnitude and matching SI prefix.

Scientific · 2 significant figures4.2 × 10⁻⁴0.00042 · engineering 420 × 10⁻⁶ · 420 micro

Value

Show as

Scientificabsolute mantissa in [1, 10)
4.2 × 10⁻⁴
Engineeringexponent a multiple of 3, so it maps to an SI prefix
420 × 10⁻⁶
Standardwritten out in full, no exponent
0.00042
E-notationwhat code and spreadsheets use
4.2e-4
SI prefixµ = 10⁻⁶
420 micro (µ)
Significant figures1.200 × 10³ has four; 1.2 × 10³ has two
2
Order of magnitudethe leading digit sits at 10⁻⁴
-4

Engineering notation pads the mantissa to 420 so the exponent can be a multiple of three. Only 2 of those digits are significant; the rest are placeholders, not measured figures.

Trailing zeros carry meaning. 1.200 × 10³ states four significant figures; 1.2 × 10³ states two. Converters that normalise through a float lose that distinction, which changes what the number claims about its own precision. Nothing here goes near a float: every form above is built digit by digit from what you typed.

Common questions

How do I convert a number to scientific or standard notation?: Enter a decimal such as 0.00042, or a scientific value such as 4.2e-4. The results update as you type. Choose Scientific, Engineering, Standard or E-notation for the large display, then use the corresponding Copy button. All four forms also appear in the output cards.
What is the difference between scientific and engineering notation?: For a nonzero value, scientific notation gives the mantissa a magnitude from 1 up to, but not including, 10. Engineering notation uses an exponent divisible by three. For example, 0.00042 becomes 4.2 × 10⁻⁴ or 420 × 10⁻⁶. The latter has the micro prefix.
Why do trailing zeros change the significant figures?: They record the precision stated by the written number. 1.200 × 10³ has four significant figures; 1.2 × 10³ has two. Both equal 1200. The converter keeps this distinction in scientific notation and warns when another form cannot express it unambiguously.
How many significant figures does 1200 have?: This tool reads 1200 as two significant figures by convention: trailing zeros without a decimal point are placeholders. Write 1200. or 1.200 × 10³ to state four. The result flags the ambiguity; it does not determine how accurately the original quantity was measured.
Can it handle very large or very small exponents?: Yes, within the exponent limit of -999,999,999 to 999,999,999 after normalisation. For example, 1e1000 keeps its exact scientific form and expands to a 1 followed by 1,000 zeros. Standard form is omitted when it would exceed 10,000 characters; the other forms remain available.
What input formats are accepted?: Use ordinary decimals, e or E notation, or powers of ten such as 4.2 × 10^-4 and 4.2 x 10^-4. Unicode superscripts also work. A value such as 42 × 10⁻⁵ is normalised to 4.2 × 10⁻⁴. Fractions, binary notation, arithmetic expressions and attached units are not accepted.
Does it round to three significant figures?: No. It counts and preserves the significant figures in your input rather than rounding to a chosen count. Enter 1.23e4 if you already want to represent that value with three significant figures; entering 1.234e4 keeps four.
Does the SI prefix result convert physical units?: No. It names the prefix matching the engineering exponent, from quecto through quetta when one exists. For 0.00042, it shows 420 micro (µ). It does not accept unit labels or convert between metres, feet, kilograms or other units.
What is the order of magnitude?: Here it is the exponent in normalised scientific notation, using the absolute value for negatives. Zero has no order of magnitude. Exponents 6 and 3 differ by three powers of ten; the actual ratio also depends on the two mantissas, so it is exactly 1,000 only when those mantissas match.

Accepted values are converted using their digits, without floating-point rounding. Normalised exponents must be between -999,999,999 and 999,999,999. Standard form is omitted above 10,000 characters. Trailing-zero integers use the stated significant-figure convention; the count does not certify measurement accuracy.