指数表記計算ツール
The detailed guide below is currently available in English.
Why scientific notation exists
Scientific notation writes every number as a mantissa between 1 and 10 times a power of ten, which keeps huge and tiny values honest at a glance. Avogadro’s number becomes 6.022 × 10²³ instead of a 602,200,000,000,000,000,000,000 string whose digit count is easy to get wrong, and the width of a proton, roughly 8.4 × 10⁻¹⁶ meters, reads instantly as "a decimal fraction". Multiplying two values in this form is a joy: multiply the mantissas, add the exponents — (2 × 10³) × (3 × 10⁴) = 6 × 10⁷ — and the same logic makes addition possible after matching exponents.
よくある質問
What does the E in 6.022e23 mean?
It is calculator shorthand for "times ten to the": 6.022e23 means 6.022 × 10²³. The E-notation row shows your number in this form, which is what spreadsheets and programming languages expect.
Why must the mantissa be at least 1?
Keeping exactly one nonzero digit before the decimal point makes the form unique — every number has exactly one standard scientific notation, so two people always write it the same way.