What is 0.00045 in scientific notation?

0.00045 is written as 4.5 × 10⁻⁴ in scientific notation, or 4.5e-4 in E-notation. The decimal point moves four places to the right, so the exponent is -4.

How do you convert a decimal to scientific notation?

Move the decimal point until exactly one non-zero digit is to its left — that is the mantissa. The number of places you moved the point gives the exponent: positive if you moved left, negative if you moved right.

What is the difference between scientific and engineering notation?

Scientific notation requires the mantissa to satisfy 1 ≤ |m| < 10, so the exponent can be any integer. Engineering notation restricts the exponent to multiples of 3 (…, -6, -3, 0, 3, 6, …) so it aligns with SI prefixes like milli, micro, kilo, mega.

E-notation is a compact form used by calculators, spreadsheets, and programming languages. 4.5e-4 means 4.5 × 10⁻⁴. The letter 'e' stands for 'times ten to the power of'.

How are significant figures related to scientific notation?

Writing a number in scientific notation makes its significant figures unambiguous — every digit in the mantissa is significant. 1200 is ambiguous (2, 3, or 4 sig figs), but 1.2 × 10³ clearly has two.

What is the order of magnitude of a number?

The order of magnitude is the exponent of the number written in scientific notation. 0.00045 has order of magnitude -4; 123,456 has order of magnitude 5.

Scientific Notation Converter

Scientific notation expresses numbers as a mantissa multiplied by a power of ten, making very large or very small values easy to read and compare. This converter handles all three common conventions in one place: scientific notation where 1 ≤ |m| < 10, engineering notation where the exponent is a multiple of 3 (aligning with SI prefixes like kilo, mega, micro, nano), and E-notation used in spreadsheets and programming languages. Enter a decimal, a mantissa-and-exponent pair, or an E-notation string, and the tool returns every canonical form, the order of magnitude, and a count of significant figures. Ideal for physics, chemistry, astronomy, electronics, and any field where numbers span many orders of magnitude.

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calendar_today Updated: April 2026

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function Enter a number

Input Mode

Decimal Value

Any real number: 0.00045, 6022000000000000000000000, -1.5, etc.

analytics All canonical forms

Scientific notation

4.5 × 10^-4

1 ≤ |m| < 10

Engineering notation 450 × 10^-6

Exponent is a multiple of 3 — aligns with SI prefixes (µ, m, k, M, G).

E-notation 4.5e-4

Decimal 0.00045

Sig Figs

Order of Magnitude

-4

Step by step

Input Values

Input Mode

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Decimal Value

Mantissa (m)

Exponent (n)

E-notation

tips_and_updates Tips

• Scientific notation requires 1 ≤ |mantissa| < 10.
• Engineering notation uses exponents that are multiples of 3 to match SI prefixes (kilo, mega, micro, nano).
• E-notation is the form used by calculators and programming languages: 4.5e-4 means 4.5 × 10⁻⁴.
• Shifting the decimal point left makes the exponent more positive; shifting right makes it more negative.
• Significant figures are counted from the first non-zero digit; leading zeros never count.

How to Use This Calculator

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Choose Input Mode

Pick decimal, scientific (m × 10^n), or E-notation.

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Enter the Number

Type the value in the form that matches your chosen mode.

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Read All Forms

See scientific, engineering, E-notation, and plain decimal forms side by side.

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Check Sig Figs

Inspect significant figure count and order of magnitude.

The Formula

Scientific notation writes any nonzero real number as a mantissa between 1 and 10 multiplied by an integer power of 10. Engineering notation restricts the exponent to multiples of 3 so it aligns with SI prefixes.

value = m × 10^n, 1 ≤ |m| < 10

lightbulb Variables Explained

m Mantissa (coefficient)
n Exponent (integer power of 10)

tips_and_updates Pro Tips

Scientific notation requires 1 ≤ |mantissa| < 10.

Engineering notation uses exponents that are multiples of 3 to match SI prefixes (kilo, mega, micro, nano).

E-notation is the form used by calculators and programming languages: 4.5e-4 means 4.5 × 10⁻⁴.

Shifting the decimal point left makes the exponent more positive; shifting right makes it more negative.

Significant figures are counted from the first non-zero digit; leading zeros never count.