Editing Template:Convert/doc (section)

==Numbers==

===Using an SI prefix: ''gigametre (Gm)'', or ''micrometre (&#x03BC;m)''===
{| class="wikitable floatright"
|+ [[Metric prefix]]es
|-
! Text
! Symbol
! Factor
|-
|quetta
| style="text-align: center;" |Q
|10<sup>30</sup>
|-
|ronna
| style="text-align: center;" |R
|10<sup>27</sup>
|-
|yotta
| style="text-align: center;" |Y
|10<sup>24</sup>
|-
|zetta
| style="text-align: center;" |Z
|10<sup>21</sup>
|-
|exa
| style="text-align: center;" |E
|10<sup>18</sup>
|-
|peta
| style="text-align: center;" |P
|10<sup>15</sup>
|-
|tera
| style="text-align: center;" |T
| 10<sup>12</sup>
|-
|giga
| style="text-align: center;" |G
| 10<sup>9</sup>
|-
|mega
| style="text-align: center;" |M
| 10<sup>6</sup>
|-
|kilo
| style="text-align: center;" |k
|10<sup>3</sup>
|-
|hecto
| style="text-align: center;" |h
|10<sup>2</sup>
|-
|deca
| style="text-align: center;" |da
|10<sup>1</sup>
|-
| colspan=2 style="text-align: center;" |(none)
|style="padding-left:0.6em; text-align:left;" | &nbsp;1
|-
|deci
| style="text-align: center;" |d
|10<sup>&minus;1</sup>
|-
|centi
| style="text-align: center;" |c
|10<sup>&minus;2</sup>
|-
|milli
| style="text-align: center;" |m
|10<sup>&minus;3</sup>
|-
|micro
| style="text-align: center;" |μ
|10<sup>&minus;6</sup>
|-
|nano
| style="text-align: center;" |n
|10<sup>&minus;9</sup>
|-
|pico
| style="text-align: center;" |p
|10<sup>&minus;12</sup>
|-
|femto
| style="text-align: center;" |f
|10<sup>−15</sup>
|-
|atto
| style="text-align: center;" |a
|10<sup>&minus;18</sup>
|-
|zepto
| style="text-align: center;" |z
|10<sup>&minus;21</sup>
|-
|yocto
| style="text-align: center;" |y
|10<sup>&minus;24</sup>
|-
|ronto
| style="text-align: center;" |r
|10<sup>&minus;27</sup>
|-
|quecto
| style="text-align: center;" |q
|10<sup>&minus;30</sup>
|}
Units can have an [[metric prefix|SI prefix]] like <code>G</code> before the unit: <code>Gm</code>, and <code>giga</code> before the name: <code>gigametre</code>. These are plain multiplication factors.

To illustrate, these are trivial calculations (from metre to metre), showing the multiplication factor:
* {{convert|12|Gm|m|abbr=on}}
* {{convert|12|μm|m|abbr=on}}

The prefix can be added before the SI unit (here: unit <code>m</code> for metre):
* <code><nowiki>{{convert|12|Gm|mi|abbr=on}}</nowiki></code> → {{convert|12|Gm|mi|abbr=on}}
* <code>Mm</code>: {{convert|12|Mm|mi|abbr=on}}
* <code>km</code>: {{convert|12|km|ft|abbr=on}}
* <code>mm</code>: {{convert|12|mm|in|abbr=on}}
* <code>&#x03BC;m</code>: {{convert|12|μm|mm|abbr=on}}
* <code>um</code>: {{convert|12|um|mm|abbr=on}} (letter "u" can be used for "&#x03BC;" here)

The prefix can be used in the output unit:
* <code><nowiki>{{convert|12000|mi|Mm|abbr=on}}</nowiki></code> → {{convert|12000|mi|Mm|abbr=on}}
* <code><nowiki>{{convert|12|in|μm|abbr=on}}</nowiki></code> → {{convert|12|in|μm|abbr=on}}

As an exception, the non-SI unit "inch" can have the "&#x03BC;" prefix too:
* <code><nowiki>{{convert|12|&#x03BC;m|μin|abbr=on}}</nowiki></code> → {{convert|12|μm|μin|abbr=on}}

{{further|Help:Convert units#SI prefixes}}

===Engineering notation: ''7 × 10<sup>6</sup> m''===

====In the unit: ''e6m''====
[[Engineering notation]] can be entered as a "prefix" to the unit:
* <code><nowiki>{{convert|70|e6m}}</nowiki></code> → {{convert|70|e6m|abbr=on}}

The same is possible for the output unit:
* <code><nowiki>{{convert|23,000,000|ft|e6m}}</nowiki></code> → {{convert|23,000,000|ft|e6m}}

Any standard unit (not a combination, multiple, or built-in unit) can have such a prefix:
* <code>e3</code> (thousand),
* <code>e6</code> (million),
* <code>e9</code> (billion),
* <code>e12</code> (trillion),
* <code>e15</code> (quadrillion).

===Scientific notation: ''1.23 × 10<sup>−14</sup>''===
In [[scientific notation]], a number is written like {{val|1.23e-14}}. The plain number has exactly one digit before the decimal point.

With {{tlf|convert}}, the input can be in e-notation such as <code>12.3e4</code>. This value is displayed as a power of ten, and the output is displayed in scientific notation, except that an output value satisfying 0.01 <= v < 1000 is shown as a normal number. In addition, if the output value is 1000 and sigfig=4 is used, the value is displayed as a normal number.
*<code><nowiki>{{convert|12.3e-15|atm|atm|abbr=on}}</nowiki></code> → {{convert|12.3e-15|atm|atm|abbr=on}}
*<code><nowiki>{{convert|0.00000005|atm|atm|abbr=on}}</nowiki></code> → {{convert|0.00000005|atm|atm|abbr=on}}

===Input with fractions: ''{{convert|1+1/2|in|mm|1}}''===
The number to convert can be written in fractions. Both <code>/</code> (keyboard slash) and <code>⁄</code> (fraction slash) are accepted:
*<code><nowiki>{{convert|1/2|in|mm|1}}</nowiki></code> → {{convert|1/2|in|mm|1}}
*<code><nowiki>{{convert|1⁄2|in|mm|1}}</nowiki></code> → {{convert|1⁄2|in|mm|1}}

With positive [[mixed number]]s (a positive integer and a fraction), use a <code>+</code> sign
*<code><nowiki>{{convert|2+1⁄2|in|mm|1}}</nowiki></code> → {{convert|2+1⁄2|in|mm|1}}

With negative mixed numbers, use a hyphen <code>-</code> and repeat it:
*<code><nowiki>{{convert|-2-1⁄2|in|mm|1}}</nowiki></code> → {{convert|-2-1⁄2|in|mm|1}}

Note that the following cases are not interpreted as mixed numbers:
*<code><nowiki>{{convert|2-1⁄2|in|mm|1}}</nowiki></code> → {{convert|2-1⁄2|in|mm|1}}. This is interpreted as a range from 2 inches to 1⁄2 inch.
*<code><nowiki>{{convert|-2+1⁄2|in|mm|1}}</nowiki></code> → {{convert|-2+1⁄2|in|mm|1}} {{nay}} This is neither a mixed number nor a range, and mathematical expressions requiring calculations are not allowed here.
*<code><nowiki>{{convert|2+½|in|mm|1}}</nowiki></code> → {{convert|2+½|in|mm|1}} {{nay}} Fractions consisting of a single Unicode character are not allowed either.

===Horizontal fraction bar: ''{{sfrac|1|2}}&nbsp;inch''===
<!-- technical restriction: TOC does not show the example horizontal bar intended here; rephrased section title-->
Using a double slash (<code>//</code>) provides a horizontal fraction bar for the original (input) unit:
* <code><nowiki>{{convert|1//2|in|mm|1}}</nowiki></code> → {{convert|1//2|in|mm|1}}
* <code><nowiki>{{convert|6+3//8|in|mm|1}}</nowiki></code> → {{convert|6+3//8|in|mm|1}}
Using a negative value for {{para|frac}} provides a horizontal fraction bar for the converted (output) unit:
*<code><nowiki>{{convert|12.7|mm|frac=-2}}</nowiki></code> → {{convert|12.7|mm|frac=-2}}
*<code><nowiki>{{convert|161.9|mm|frac=-8}}</nowiki></code> → {{convert|161.9|mm|frac=-8}}

===Thousands separator: ''1,000 mi'' or ''1000 mi''===
In input, a comma for thousands separator is accepted but not required; a gap (space) is not accepted. In output, by default, the thousand separator is the comma:
* <code><nowiki>{{convert|1234567|m|ft}}</nowiki></code> → {{convert|1234567|m|ft}}
* <code><nowiki>{{convert|1,234,567|m|ft}}</nowiki></code> → {{convert|1,234,567|m|ft}}

Set {{para|comma|off}} to remove the separator from the output:
* <code><nowiki>{{convert|1234567|m|ft|comma=off}}</nowiki></code> → {{convert|1234567|m|ft|comma=off}}

Use {{para|comma|gaps}} to use digit grouping by gap (thin space) as a thousands separator:
* <code><nowiki>{{convert|1234567|m|ft|comma=gaps}}</nowiki></code> → {{convert|1234567|m|ft|comma=gaps}}
Default behavior, for comparison:
* <code><nowiki>{{convert|1234567|m|ft}}</nowiki></code> → {{convert|1234567|m|ft}}

Setting {{para|comma|5}} will only add the separator when the number of digits is 5 or more:
* <code><nowiki>{{convert|1234|m|ft|comma=5}}</nowiki></code> → {{convert|1234|m|ft|comma=5}}
* <code><nowiki>{{convert|1234567|m|ft|comma=5}}</nowiki></code> → {{convert|1234567|m|ft|comma=5}}
Default behavior, for comparison:
* <code><nowiki>{{convert|1234|m|ft}}</nowiki></code> → {{convert|1234|m|ft}}