Metric prefixes multiply SI base units by powers of 10. Kilometer = kilo (1000) x meter. Milligram = milli (0.001) x gram. Standard worldwide. Simple and systematic.

• Prefix x base unit
• Powers of 10
• kilo = 1000x (10^3)
• milli = 0.001x (10^-3)

Large prefixes increase by 1000x each step: kilo, mega, giga, tera. Small prefixes decrease by 1000x: milli, micro, nano, pico. Symmetrical and logical! Easy to learn.

• 1000x steps (10^3)
• kilo → mega → giga
• milli → micro → nano
• Symmetrical pattern

Same prefixes work for ALL SI units. Kilogram, kilometer, kilowatt. Milligram, millimeter, milliwatt. Learn once, use everywhere. Foundation of metric system.

• Works for all SI units
• Length: meter (m)
• Mass: gram (g)
• Power: watt (W)

kilo (k) = 1000. mega (M) = million. giga (G) = billion. tera (T) = trillion. Common in computing (gigabyte), science (megawatt), everyday (kilometer).

• kilo (k): 10^3 = 1,000
• mega (M): 10^6 = 1,000,000
• giga (G): 10^9 = 1,000,000,000
• tera (T): 10^12 = trillion

milli (m) = 0.001 (thousandth). micro (µ) = 0.000001 (millionth). nano (n) = billionth. pico (p) = trillionth. Essential in medicine, electronics, chemistry.

• milli (m): 10^-3 = 0.001
• micro (µ): 10^-6 = 0.000001
• nano (n): 10^-9 = billionth
• pico (p): 10^-12 = trillionth

quetta (Q) = 10^30, ronna (R) = 10^27 for huge scales. quecto (q) = 10^-30, ronto (r) = 10^-27 for tiny scales. Added for data science and quantum physics. Largest official additions ever!

• quetta (Q): 10^30 (largest)
• ronna (R): 10^27
• ronto (r): 10^-27
• quecto (q): 10^-30 (smallest)

Prefixes are simply powers of 10. 10^3 = 1000 = kilo. 10^-3 = 0.001 = milli. Exponent rules apply: 10^3 x 10^6 = 10^9 (kilo x mega = giga).

• 10^3 = 1000 (kilo)
• 10^-3 = 0.001 (milli)
• Multiply: add exponents
• Divide: subtract exponents

Count steps between prefixes. kilo to mega = 1 step = x1000. milli to nano = 2 steps = x1,000,000. Each step = x1000 (or /1000 going down).

• 1 step = x1000 or /1000
• kilo → mega: x1000
• milli → micro → nano: x1,000,000
• Count the steps!

Large and small prefixes mirror each other. kilo (10^3) mirrors milli (10^-3). mega (10^6) mirrors micro (10^-6). Beautiful mathematical symmetry!

• kilo ↔ milli (10^±3)
• mega ↔ micro (10^±6)
• giga ↔ nano (10^±9)
• Perfect symmetry

Kilobyte, megabyte, gigabyte, terabyte. Now petabyte (PB), exabyte (EB), zettabyte (ZB), yottabyte (YB)! World data approaching zettabyte scale. New prefixes ronna/quetta ready for future.

• GB: gigabyte (phones)
• TB: terabyte (computers)
• PB: petabyte (data centers)
• ZB: zettabyte (global data)

Nanometer (nm): virus size, DNA width. Micrometer (µm): cell size, bacteria. Millimeter (mm): common measurements. Picometer (pm): atomic scale. Essential for research!

• mm: millimeter (everyday)
• µm: micrometer (cells)
• nm: nanometer (molecules)
• pm: picometer (atoms)

Kilowatt (kW): home appliances. Megawatt (MW): industrial, wind turbines. Gigawatt (GW): power plants, city power. Terawatt (TW): national/global power scales.

• kW: kilowatt (home)
• MW: megawatt (factory)
• GW: gigawatt (power plant)
• TW: terawatt (national grid)

Each step = x1000 or /1000. kilo → mega = 1 step up = x1000. mega → kilo = 1 step down = /1000. Count steps, multiply by 1000 each!

• 1 step = x1000
• kilo → giga: 2 steps = x1,000,000
• nano → milli: 2 steps = /1,000,000
• Easy pattern!

Use exponents! kilo = 10^3, mega = 10^6. Subtract exponents: 10^6 / 10^3 = 10^3 = 1000. mega is 1000x larger than kilo.

• mega = 10^6
• kilo = 10^3
• 10^6 / 10^3 = 10^3 = 1000
• Subtract exponents

Memorize pairs! kilo ↔ milli = 10^±3. mega ↔ micro = 10^±6. giga ↔ nano = 10^±9. Mirror pairs!

• kilo = 10^3, milli = 10^-3
• mega = 10^6, micro = 10^-6
• giga = 10^9, nano = 10^-9
• Perfect mirrors!

Hard drive has 2 TB capacity. How many GB is that?

tera → giga = 1 step down = x1000. 2 TB x 1000 = 2000 GB. Or: 2 x 10^12 / 10^9 = 2 x 10^3 = 2000.

Red light wavelength = 650 nm. What is this in micrometers?

nano → micro = 1 step up = /1000. 650 nm / 1000 = 0.65 µm. Or: 650 x 10^-9 / 10^-6 = 0.65.

Power plant outputs 1.5 GW. How many MW?

giga → mega = 1 step down = x1000. 1.5 GW x 1000 = 1500 MW. Or: 1.5 x 10^9 / 10^6 = 1500.

Metric system based on powers of 10 for simplicity. 1000 = 10^3 is a nice round power. Easy to remember and calculate. Original prefixes (kilo, hecto, deka, deci, centi, milli) from French metric system 1795.

quetta, ronna, ronto, quecto adopted November 2022 at 27th CGPM (General Conference on Weights and Measures). First new prefixes since 1991 (yotta/zetta). Needed for data science boom and quantum physics!

Global internet traffic in 2023 exceeded 1 zettabyte per year! 1 ZB = 1,000,000,000,000,000,000,000 bytes. That's 1 billion terabytes! Growing exponentially. Yottabyte scale approaching.

DNA double helix width ≈ 2 nm. Human hair width ≈ 80,000 nm (80 µm). So 40,000 DNA helixes could fit across a human hair! Nano = billionth, incredibly tiny!

Smallest meaningful length in physics: Planck length ≈ 10^-35 meters. That's 100,000 quectometers (10^-35 / 10^-30 = 10^-5)! Quantum gravity scale. Even quecto doesn't cover it fully!

Large prefixes from Greek: kilo (thousand), mega (great), giga (giant), tera (monster). Small from Latin: milli (thousandth), micro (small), nano (dwarf). Newest from made-up words to avoid conflicts!

Historical and practical reasons. Powers of 1000 (10^3) provide nice scaling without too many intermediate steps. Original French metric had 10x steps (deka, hecto) but 1000x steps (kilo, mega, giga) became standard for scientific work. Easier to work with: kilo (10^3), mega (10^6), giga (10^9) vs needing more intermediate names.

kilo (k) = 1000 (decimal, SI standard). kibi (Ki) = 1024 (binary, IEC standard). In computing, 1 kilobyte (kB) = 1000 bytes (SI) but 1 kibibyte (KiB) = 1024 bytes. Hard drives use kB (decimal), RAM often uses KiB (binary). Can cause confusion! Always check which system is being used.

Data explosion! Global data production growing exponentially. By 2030, estimated to reach yottabyte scale. Also, theoretical physics and cosmology need larger scales. quetta/ronna added preemptively in 2022. Better to have them ready than scramble later!

No! Can't have 'kilomega' or 'millimicro'. Each measurement uses ONE prefix. Exception: compound units like km/h (kilometer per hour) where each unit can have its own prefix. But single quantity = single prefix maximum.

µ (Greek letter mu) is official SI symbol for micro. Some systems can't display µ, so 'u' is informal substitute (like 'um' for micrometer). But official symbol is µ. Similarly, Ω (omega) for ohm, not O.

Nothing officially! quetta (10^30) is largest, quecto (10^-30) is smallest as of 2024. If needed, BIPM could add more in future. Some propose 'xona' (10^33) but not official. For now, quetta/quecto are the limits!