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Tera- (prefix) — Definition, Formula & Examples

Tera- is a metric prefix meaning one trillion, or 1,000,000,000,000. You see it most often in technology, where storage and data sizes are measured in terabytes (TB).

Tera- (symbol T) is the SI prefix denoting a factor of 101210^{12}, equivalent to multiplying a base unit by one trillion. It was adopted as part of the International System of Units in 1960.

Key Formula

1  T(unit)=1012  (units)1\;\text{T(unit)} = 10^{12}\;\text{(units)}
Where:
  • TT = The tera- prefix symbol, representing a factor of 10^12

How It Works

To convert a tera-unit to the base unit, multiply by 101210^{12}. For example, 1 terawatt equals 101210^{12} watts. To go the other direction, divide the base unit by 101210^{12}. The prefix follows the same pattern as other metric prefixes: kilo- (10310^3), mega- (10610^6), giga- (10910^9), tera- (101210^{12}). Each step up multiplies by 1,000.

Worked Example

Problem: A computer hard drive holds 2 terabytes (TB) of data. How many gigabytes (GB) is that?
Recall the prefixes: Tera- means 101210^{12} and giga- means 10910^{9}.
Find the conversion factor: Divide 101210^{12} by 10910^{9} to find how many giga-units fit in one tera-unit.
1012109=103=1,000\frac{10^{12}}{10^{9}} = 10^{3} = 1{,}000
Multiply: Multiply 2 TB by 1,000 GB per TB.
2×1,000=2,000  GB2 \times 1{,}000 = 2{,}000 \;\text{GB}
Answer: 2 terabytes equals 2,000 gigabytes.

Why It Matters

Tera- appears constantly in science and technology. Hard drive capacities are listed in terabytes, and global energy production is measured in terawatt-hours. Understanding this prefix helps you interpret real-world data in science classes and news reports.

Common Mistakes

Mistake: Confusing tera- (101210^{12}) with giga- (10910^{9}).
Correction: Remember the order: kilo (10310^3), mega (10610^6), giga (10910^9), tera (101210^{12}). Each prefix is 1,000 times larger than the one before it.