Scientific notation calculator: convert between decimal, scientific, E and engineering notation, and add, subtract, multiply or divide with sig-fig rules.
299792458 is 2.99792458 × 10⁸ in scientific notation, 2.99792458e8 in E notation and 299.792458 × 10⁶ in engineering notation, with 9 significant figures.
299792458 has 9 significant figures.
The point moves 8 places left to sit after the first significant digit, so the exponent is 8.
Engineering notation lowers the exponent to a multiple of 3 (6); E notation writes “× 10^” as e: 2.99792458e8.
Scientific notation writes a number as a × 10ⁿ with 1 ≤ |a| < 10, so 299,792,458 becomes 2.99792458 × 10⁸: the decimal point moves 8 places left and the exponent counts the moves. E notation writes the same number as 2.99792458e8, and engineering notation keeps the exponent a multiple of 3 (299.792458 × 10⁶) so it lines up with SI prefixes such as mega. In the UK this form is called standard form.
The digits you type set the significant figures, and they are kept: 0.005600 converts to 5.600 × 10⁻³ with four. For arithmetic, products and quotients keep the fewest significant figures of the inputs, and sums and differences keep the least precise decimal place, the rules in OpenStax Chemistry 2e §1.5. For example, 1.2 × 10⁵ × 3.45 × 10⁻² = 4,140 is reported as 4.1 × 10³.
Trailing zeros in a whole number without a decimal point, as in 93,000,000, are treated as placeholders; type 93,000,000. or 9.300 × 10^7 when they were measured.
Checked against: SI defining constant c = 299 792 458 m/s (BIPM SI Brochure 9th ed.); notation forms by hand
Checked against: Calculator Soup scientific notation converter: 357,096 = 3.57096 × 10^5
Checked against: Calculator Soup scientific notation converter: 0.005600 = 5.600 × 10^-3, trailing zeros kept as significant
Checked against: Omni Calculator scientific notation page: 0.00057 = 5.7 × 10⁻⁴; engineering form by moving to the next lower multiple of 3
Move the decimal point until one non-zero digit is left of it, and count the moves. Moving left gives a positive exponent and moving right a negative one. 357,096 needs 5 moves left, so it is 3.57096 × 10⁵; 0.005600 needs 3 moves right, so it is 5.600 × 10⁻³. Keep every significant digit, including the trailing zeros after a decimal point.
Multiply or divide the leading numbers and add or subtract the exponents, then renormalize. (1.2 × 10⁵) × (3.45 × 10⁻²) = 4.14 × 10³, and (6.0 × 10⁴) ÷ (1.5 × 10⁻²) = 4.0 × 10⁶. With measured values, round the answer to the fewest significant figures among the inputs: 1.2 has two, so the product is 4.1 × 10³.
Rewrite both numbers with the same power of ten, add or subtract the leading numbers, then renormalize. 1.225 × 10⁵ + 3.655 × 10³ = 1.225 × 10⁵ + 0.03655 × 10⁵ = 1.26155 × 10⁵. For measurements, round to the least precise decimal place: 122,500 is known to the hundreds, so the sum is 126,200, or 1.262 × 10⁵.
E notation is scientific notation for calculators, spreadsheets and programming languages, where E (or e) stands for “times ten to the power”. 6.02E23 means 6.02 × 10²³, and 5.6e-3 means 5.6 × 10⁻³ = 0.0056. Excel shows numbers of 12 or more digits this way in the General format, and most languages accept it in number literals.
Engineering notation restricts the exponent to multiples of 3, so the leading number is between 1 and 1,000. 0.00057 is 5.7 × 10⁻⁴ in scientific notation but 570 × 10⁻⁶ in engineering notation, which reads directly as 570 micro-units. The multiples of 3 match the SI prefixes from quecto (10⁻³⁰) to quetta (10³⁰), the range set by the 2022 General Conference on Weights and Measures.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 10 worked examples whose answers come from independent sources; for example, “Speed of light, 299,792,458 m/s (default)” is checked against SI defining constant c = 299 792 458 m/s (BIPM SI Brochure 9th ed.); notation forms by hand.
OpenStax, Chemistry 2e, §1.5 Measurement uncertainty, accuracy, and precision (significant-figure rules); BIPM, SI prefixes (SI Brochure, 9th edition, and CGPM 2022 Resolution 3); NIST SP 811, Guide for the Use of the International System of Units (SI), chapters 7 and 10 (expressing values and printing numbers).
10 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
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