Scientific & Engineering Notation Converter (SI Prefix, E-Notation)
Convert numbers between decimal, scientific (a × 10^b), engineering (exponent multiple of 3), SI-prefixed (12.3k, 4.7µ), and E-notation (1.5e-9) — with adjustable significant figures, exact BigInt mantissa math, full SI prefix table from yocto to quetta (plus binary IEC prefixes), batch list conversion, and rounding-mode selection. 100% client-side & offline.
About Scientific & Engineering Notation Converter (SI Prefix, E-Notation)
Convert numbers between decimal, scientific (a × 10^b), engineering (exponent multiple of 3), SI-prefixed (12.3k, 4.7µ), and E-notation (1.5e-9) — with adjustable significant figures, exact BigInt mantissa math, full SI prefix table from yocto to quetta (plus binary IEC prefixes), batch list conversion, and rounding-mode selection. 100% client-side & offline. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
Which notation forms does this converter support?
Five forms, all kept in sync: plain decimal, scientific (a × 10^b with 1 ≤ |a| < 10), engineering (exponent is always a multiple of 3, mantissa 1 ≤ |a| < 1000), SI-prefixed (12.3k, 4.7µ, 2.5Qi), and E-notation (1.5e-9). Type any of them and the others update live.
How does significant-figure control work?
Pick how many significant figures (1–50) you want and the converter rounds every form consistently. The rounding mode is selectable (half-up, half-even, down, up, half-down) so you can match IEEE 754, banking, or scientific conventions. Trailing zeros are preserved when sig-figs demand them (e.g. 1.200 × 10³ at 4 sig-figs).
Does it stay exact for very large or very small numbers?
Yes. The mantissa is parsed as a BigInt (sign + integer-digits + fractional-digits) and the exponent is handled as a separate integer, so values like 6.02214076e23 (Avogadro) or 1.616255e-35 (Planck length) convert without float round-off. SI prefix output uses the same exact core, with fallback to scientific form when the exponent falls outside the yocto (10⁻²⁴) … quetta (10³⁰) range.
Which SI and binary prefixes are included?
All 24 metric SI prefixes from quetta (10³⁰) down to yocto (10⁻²⁴), including the micro (µ) sign. As an optional toggle, all 8 binary IEC prefixes from kibi (Ki = 2¹⁰) to yobi (Yi = 2⁸⁰) are available for byte-style values. When the exponent lies outside the prefix range, the converter falls back to scientific notation so you never get a misleading result.
What extra features does this tool have compared to other notation converters?
(1) Decimal ↔ scientific ↔ engineering ↔ SI-prefix ↔ E-notation, all live. (2) Significant-figure control (1–50). (3) Rounding-mode selector (5 modes). (4) Exact BigInt mantissa — no float rounding for huge/tiny values. (5) Full SI prefix range yocto → quetta. (6) Binary IEC prefix toggle (Ki–Yi). (7) Batch list conversion (one input per line → all forms). (8) Copy each form individually. (9) History (localStorage, last 20). (10) Shareable URL. (11) Auto-detect input form. 100% client-side and offline — your numbers never leave the device.
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