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SI Prefix Table

Browse the complete SI prefix table with decimal multipliers, powers of ten, symbols, scientific notation, and metric unit prefixes used in engineering, electronics, science, and mathematics.

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SI Prefix Multi-way Converter
Name
Symbol
Power
Decimal
Please check selected options.
CONVERTER RESULTS
Selected Prefix Name
Standard Symbol
Scientific Multiplier
Full Decimal Value

Input Parameters Specification

Prefix Unit NameThe official nomenclature designation (such as milli, micro, kilo, mega) declared under standard SI metrics.
System SymbolThe short-hand representation case-sensitive character (e.g. m, µ, k, M) used to denote the multiplier.
Scientific Power FactorThe base-10 exponential multiplier value (e.g. 10^-6 or 10^3) representing the scale multiplier.
Decimal Form LayoutThe long expanded plain numerical representation showing complete leading or trailing zeros.

Practical Operational Examples

Microscopic Sizing

A standard capacitor measures 1 microfarad (µF). This uses the symbol 'µ', representing a factor of 10⁻⁶ and a decimal size of 0.000001.

Computer Processing Speed

Computer CPUs operate at gigahertz (GHz) speeds. Sizing this shows a factor of 10⁹, which expands to a massive 1,000,000,000 Hz.

Grid Power Distribution

High voltage lines carry megawatts (MW) of power. This maps to a prefix of mega (M), which represents exactly 1,000,000 Watts.

Subatomic Physics

Subatomic distances are measured in femtometers (fm). The femto prefix (f) represents a tiny power of 10⁻¹⁵ meters.

Formulas & Mathematical Logic

SI Prefixes simplify writing extremely large or small numbers by using logical factors of ten.

Conversion formula: Value with prefix = Base Value / (10^Power)
Inverse conversion: Base Value = Value with prefix × 10^Power

This systematic logarithmic scaling system lets scientists write 1,000,000,000,000,000,000,000,000 grams cleanly as 1 yottagram (Yg), or 0.000000000001 seconds as 1 picosecond (ps).

How to Use This Calculator

Choose any one of the four parameters (Name, Symbol, Power, or Decimal) from its respective dropdown list.
Click the orange Convert button to instantly sync all four dropdown menus to the same selected index.
Review the synchronized outputs across all remaining dropdown menus.
Examine the resulting result cards below to see clear, high-resolution details of the chosen prefix.
Use the decimal expansions to perform manual conversions on physical engineering calculations.

About This Calculator

Instantly convert between SI metric prefix names, symbols, and exponential factors.

The CalcBoy SI Prefixes Multi-Converter is an interactive, fully synchronized lookup tool for standard metric prefixes.

The International System of Units (SI) defines a series of standard metric prefixes used to scale physical measurements across vast ranges of magnitude. Standardized in 1960 and managed by the International Bureau of Weights and Measures (BIPM), these prefixes are essential across all branches of science, chemistry, physics, and engineering. They eliminate the need to write out long, error-prone strings of leading or trailing zeros.

This unified calculator is designed as a fully reactive multi-way converter. Unlike standard calculators where you can only convert in one direction, this tool synchronizes all four standard parameters (Prefix Name, Symbol, Power of 10, and Expanded Decimal form) in real-time. Changing any single dropdown instantly updates the other three, providing a clear visual representation of that specific metric scale.

Always verify unit casing when writing engineering notes. Some symbols are highly case-sensitive; for instance, lowercase 'm' represents milli (10⁻³), whereas uppercase 'M' represents mega (10⁶). Sizing errors caused by mismatched cases can completely ruin calculations.

Main BenefitProvides highly responsive, multi-way synchronization of all metric prefix units.
Scope CoveredCovers massive yotta (10²⁴) sizes down to subatomic yocto (10⁻²⁴) scales.
Format SupportSynchronizes symbols, full names, exponential factors, and expanded decimals.
Case SensitivityLowercase symbols represent smaller sub-units, while uppercase symbols generally represent larger units.
Note: In 2022, the BIPM officially added four new prefixes to the SI system: ronna (10²⁷), quetta (10³⁰), ronto (10⁻²⁷), and quecto (10⁻³⁰) to accommodate massive global data scales.

Standard SI Prefixes Reference Table

Reference guide containing standard factors, names, symbols, and decimal values for all standard SI prefixes.

Factor Prefix Name Symbol Decimal Representation
10²⁴yottaY1 000 000 000 000 000 000 000 000
10²¹zettaZ1 000 000 000 000 000 000 000
10¹⁸exaE1 000 000 000 000 000 000
10¹⁵petaP1 000 000 000 000 000
10¹²teraT1 000 000 000 000
10⁹gigaG1 000 000 000
10⁶megaM1 000 000
10³kilok1 000
10²hectoh100
10¹decada10
10⁻¹decid0.1
10⁻²centic0.01
10⁻³millim0.001
10⁻⁶microµ0.000 001
10⁻⁹nanon0.000 000 001
10⁻¹²picop0.000 000 000 001
10⁻¹⁵femtof0.000 000 000 000 001
10⁻¹⁸attoa0.000 000 000 000 000 001
10⁻²¹zeptoz0.000 000 000 000 000 000 001
10⁻²⁴yoctoy0.000 000 000 000 000 000 000 001

Frequently Asked Questions

1. Why are some SI symbols capitalized and others lowercase?

Standard SI naming rules capitalize symbols representing multiplier values equal to or greater than Mega (10⁶, e.g. M, G, T, P), while sub-unit multipliers (e.g. m, µ, n, p) use lowercase to prevent case confusion.

2. What is the abbreviation symbol for the micro prefix?

The standard symbol is the Greek letter mu (µ). In environments where Greek letters are unavailable, it is sometimes written as the lowercase letter 'u' (e.g. uF instead of µF).

3. Are there any newer SI prefixes beyond yotta and yocto?

Yes. In November 2022, the BIPM officially established four new prefixes: ronna (R, 10²⁷) and quetta (Q, 10³⁰) for massive scales, and ronto (r, 10⁻²⁷) and quecto (q, 10⁻³⁰) for subatomic scales.

4. Why do computer storage capacities (like gigabytes) sometimes seem inaccurate?

Computers operate on a binary base-2 scale, where a kilobyte is 1,024 bytes (not 1,000 bytes). To avoid confusion, standard binary prefixes like kibibyte (KiB), mebibyte (MiB), and gibibyte (GiB) are used to represent exact base-2 scales.

5. What is the relationship between milli, micro, and nano scales?

Each of these standard sub-units is exactly 1,000 times smaller than the previous one: 1 milliunit equals 1,000 microunits, and 1 microunit equals 1,000 nanounits.

6. Why is it important to use SI prefixes in electrical engineering?

Electrical values span massive ranges (e.g., generator power lines carry megawatt loads, while semiconductor caches operate on picofarad scales). SI prefixes make calculations clean and readable, preventing errors caused by writing long strings of zeros.

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About this tool

SI Prefix Table is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.