About this calculator
Type a number such as 0.00045, 12,300 or 4.5e-4 and get it in scientific notation (standard form), E notation, engineering notation and as an ordinary decimal, with its significant figures.
The conversion is done on the digits themselves, so there are no rounding surprises.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
0.00045
- Scientific notation
- 4.5 × 10⁻⁴
- E notation
- 4.5e-4
- Engineering notation
- 450 × 10⁻⁶
- Ordinary number
- 0.00045
- Significant figures
- 2
0.00045 in scientific notation is 4.5 × 10⁻⁴.
Show the working
- Move the decimal point until there is one non-zero digit in front of it: 4.5.
- You moved it 4 places right, so the power of ten is -4.
- Result: 4.5 × 10⁻⁴.
12,300
- Scientific notation
- 1.23 × 10⁴
- E notation
- 1.23e4
- Engineering notation
- 12.3 × 10³
- Ordinary number
- 12,300
- Significant figures
- 3
12300 in scientific notation is 1.23 × 10⁴.
Show the working
- Move the decimal point until there is one non-zero digit in front of it: 1.23.
- You moved it 4 places left, so the power of ten is 4.
- Result: 1.23 × 10⁴.
6.022e23 (Avogadro's number)
- Scientific notation
- 6.022 × 10²³
- E notation
- 6.022e23
- Engineering notation
- 602.2 × 10²¹
- Ordinary number
- 602,200,000,000,000,000,000,000
- Significant figures
- 4
6.022e23 in scientific notation is 6.022 × 10²³.
Show the working
- Move the decimal point until there is one non-zero digit in front of it: 6.022.
- You moved it 23 places left, so the power of ten is 23.
- Result: 6.022 × 10²³.
What scientific notation is
Scientific notation (called standard form in UK schools) writes a number as a × 10ⁿ, where a is at least 1 and less than 10. So 4,500 is 4.5 × 10³ and 0.00045 is 4.5 × 10⁻⁴. It makes very large and very small numbers easy to read and compare.
E notation and engineering notation
E notation is how calculators and spreadsheets show it: 4.5e-4 means 4.5 × 10⁻⁴. Engineering notation always uses a power of ten that is a multiple of 3 (10³, 10⁻⁶…), so the numbers line up with SI prefixes like kilo, milli and micro: 450 × 10⁻⁶ is 450 micro.
Significant figures
Significant figures are the meaningful digits: leading zeros never count, zeros between digits do, and trailing zeros count only when there is a decimal point. So 0.00045 has 2, 1.200 has 4, and 12,300 is counted as 3 because the trailing zeros are ambiguous.
Frequently asked questions
How do I write 0.00045 in scientific notation?
4.5 × 10⁻⁴.
What does 1.5e3 mean?
1.5 × 10³, which is 1,500.
What is standard form?
In the UK, standard form is another name for scientific notation.
Can I type a number already in E notation?
Yes, for example 6.022e23 or 4.5e-4.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.