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Convert decimals and E notation both ways (2.5e-4, 5e23). Every digit is kept, big numbers are written in full, and a slider rounds to 1 to 15 sig figs.

📘 How to Use

  1. Type a number such as 2300000 into Decimal Number (Standard), and Scientific Notation (E-Notation) shows 2.3e+6.
  2. Type a value such as 1.5e-3 into Scientific Notation (E-Notation), and Decimal Number (Standard) shows 0.0015.
  3. To round, move the Significant Figures slider (the right end means no rounding).

Scientific Notation Converter

No rounding

When the part dropped is exactly 5, the last digit kept is made even (2.25 at 2 figures gives 2.2e+0, 2.35 gives 2.4e+0).

SI Prefix Reference

Prefix Symbol Factor (Exponential)
GigaG1e+9
MegaM1e+6
Kilok1e+3
Millim1e-3
Microμ1e-6
Nanon1e-9

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Article

Convert Scientific Notation: Tame Massive Numbers

Stop counting zeros. Quickly switch between standard decimals and scientific notation (E-notation) while maintaining perfect precision.

💡 Why Use This Converter?

Reading extremely large or small numbers is prone to human error, whether you're debugging code or writing a lab report.

  • Let It Count the Zeros: Turn 0.00000045 into 4.5e-7, or write 5e23 out as all 24 digits.
  • Eliminate Errors: Prevent "off-by-one" mistakes in your calculations and data entry.
  • Control Precision: Use the Significant Figures slider to match your specific reporting requirements.

📘 How to Use It

  • Convert Decimals to Scientific: Enter a standard number like 1000000 to see it as 1e+6.
  • Convert Scientific to Decimal: Input 2.5e-4 to generate 0.00025.
  • Adjust Sig Figs: At the right end ("No rounding") every digit you entered is kept. Pick 1 to 15 to round to that many significant figures. When the part dropped is exactly 5, the last digit kept is made even (2.25 at 2 gives 2.2e+0, 2.35 at 2 gives 2.4e+0).
  • Paste Any Common Form: 1.2E+05, 1.2×10^5, 1.2×10⁵, 120,000 and the Indian grouping 1,20,000 are all read as the same number. A comma is read only as a thousands separator, so use a dot for decimals. A single comma counts as a separator only with one to three digits (not starting with 0) before it and exactly three after it, as in 1,234: for 1,5 or 0,125 the tool shows no result and a note asking for a dot instead.

🧐 FAQ

What does the "e" stand for? It means "times ten raised to the power of": the number after the e is the power of 10. For example, 5e+2 represents 5 × 10², which equals 500.

Why do trailing zeros appear or disappear? With the slider at "No rounding", the result shows exactly the digits you entered, with no padding. Zeros after a decimal point are kept (1.500 gives 1.500e+0). Zeros at the end of a whole number may be significant or may only mark the place value, and the digits alone do not tell you which. With no rounding, the tool treats them as place value and drops them, so 2300000 gives 2.3e+6. If those zeros are significant (a measured value, for example), choose the number of significant figures on the slider: the result then keeps exactly that many digits, trailing zeros included (2300000 at 6 gives 2.30000e+6).

Is there a size limit? Digits are shifted as text instead of being stored as floating-point numbers, so no digit you enter is lost. Once the number is written in E notation, its exponent (the number after "e") can range from -100000 to +100000.

📚 The Backstory

Scientific notation is often called "Standard Form" in the UK. "E" notation lets you write an exponent on a single line of plain text, without superscripts. It already appears in IBM's 1956 programmer's manual for FORTRAN on the IBM 704 (5.0E3 = 5.0 × 10³), and FORTRAN itself was released in 1957. The HP-35 of 1972, which the IEEE commemorates as the first handheld scientific calculator, could display numbers in a form close to scientific notation.