# Help:Convert messages

This page describes the error and warning messages reported by Module:Convert if a problem is detected while using {{convert}} to convert a value from one unit of measurement to another.

If a problem cannot readily be resolved, please report it at one of the following.

## Error and warning messages

### Needs a number

Mouseover the message to see further information.[a]

• {{convert|123|m|ft}} → 123 metres (404 ft)
• {{convert||m|ft}}[convert: needs a number]

An input number is required. In the first example above, the input number is 123.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Needs another number

Mouseover the message to see further information.[a]

The first input number was specified, but the range used requires another number.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Invalid number

Mouseover the message to see further information.[a]

• {{convert|1|km|ft}} → 1 kilometre (3,300 ft)
• {{convert|km|ft}}[convert: invalid number]

A number to be converted can be entered as in these examples: 1.23 or 1,234 or -0.9.

Fractions are entered as in these examples: 1+2/3 (1 23) or -1-2/3 (−1 23) or 2/3 (23).

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Number overflow

Mouseover the message to see further information.[a]

• {{convert|1e290|m|ft}} → 1e290 metres (3.3×10290 ft)
• {{convert|1e310|m|ft}}[convert: number overflow]

This error occurs if a number exceeds the range of values available for calculations. The number 1e290 means 1×10290.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Invalid precision

Mouseover the message to see further information.[a]

• {{convert|21455|acre|ha|2}} → 21,455 acres (8,682.53 ha)
• {{convert|21455|acre|ha|-2}} → 21,455 acres (8,700 ha)
• {{convert|21455|acre|ha|2.5}} → 21,455 acres (8,683 ha)[convert: invalid precision]

A precision value is entered after the conversion information. For example, |2 gives a result that is rounded to two decimal places, while |-2 rounds to the nearest 100 so that two zeroes occur at the end of the number. This message will only appear if warnings have been enabled.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Precision too large

Mouseover the message to see further information.[a]

• {{convert|123|m|ft|2}} → 123 metres (403.54 ft)
• {{convert|123|m|ft|200}}[convert: precision too large]

Generally there is no reason to use a precision of more than a few decimal places, however, larger values may be used. The error shown occurs if the requested precision is higher than the maximum supported by the server.

A negative precision rounds to the nearest 10 (parameter |-1), or nearest 100 (|-2), or nearest 1000 (|-3), etc. A large negative precision produces a zero output.

• {{convert|123|m|ft|-2}} → 123 metres (400 ft)
• {{convert|123|m|ft|-200}} → 123 metres (0 ft)

Using a very small input value can cause the default precision to exceed the limit (1.234e-200 is 1.234×10−200). For such very small values, it is better to use the |sigfig= option.

• {{convert|1.234|m|ft}} → 1.234 metres (4.05 ft)
• {{convert|1.234e-200|m|ft}}[convert: precision too large]
• {{convert|1.234e-200|m|ft|sigfig=3}} → 1.234e-200 metres (4.05×10−200 ft)

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Invalid fraction

Mouseover the message to see further information.[a]

• {{convert|12.31|m|ftin|frac=8}} → 12.31 metres (40 ft 4 58 in)
• {{convert|12.31|m|ftin|frac=1}} → 12.31 metres (40 ft 5 in)
• {{convert/warning|12.31|m|ftin|frac=on}} → 12.31 metres (40 ft 5 in)[convert: invalid fraction]

A fraction denominator can be specified to display results with a fraction where appropriate. For example, |frac=8 specifies that the value should be rounded to the nearest eighth, and that a fraction should be included if necessary. A fraction denominator must be a whole number with value 2 or more. This message will only appear if warnings have been enabled.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Invalid sigfig

Mouseover the message to see further information.[a]

• {{convert|1234|ft|m|sigfig=2}} → 1,234 feet (380 m)
• {{convert|1234|ft|m|sigfig=0}} → 1,234 feet (376 m)[convert: invalid sigfig]
• {{convert|1234|ft|m|sigfig=2.5}} → 1,234 feet (376 m)[convert: invalid sigfig]

The number of significant figures in the result can be specified. For example, |sigfig=2 requests two significant figures. The number of significant figures must be a whole number with value 1 or more. This message will only appear if warnings have been enabled.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Empty option

Mouseover the message to see further information.[a]

• {{convert|123|m|ft|sp=us}} → 123 meters (404 ft)
• {{convert|123|m|ft|sp=}} → 123 metres (404 ft)[convert: empty option]

The option |sp=us specifies that US spelling should be used ("meters" instead of "metres"). However, |sp= has no effect as no value is specified. This message will only appear if all warnings have been enabled.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Invalid option

Mouseover the message to see further information.[a]

• {{convert|123|m|ft|abbr=off}} → 123 metres (404 feet)
• {{convert|123|m|ft|abr=off}} → 123 metres (404 ft)[convert: invalid option]

The option |abbr=off specifies that abbreviations are off, that is, unit names will be used instead of symbols. By contrast, |abr=off is ignored because "abr" is not the name of an option. This message will only appear if warnings have been enabled.

Pages with this error are automatically placed in Category:Convert invalid options.[b]

### Needs unit name

Mouseover the message to see further information.[a]

A unit code must be specified following the input number or numbers.

Pages with this error are automatically placed in Category:Convert invalid units.[b]

### Unknown unit

Mouseover the message to see further information.[a]

Each unit code must exactly match a known unit, case sensitive. A simplified list of unit codes is at Help:Convert units, and all available unit codes are here.

Pages with this error are automatically placed in Category:Convert invalid units.[b]

### Unit mismatch

Mouseover the message to see further information.[a]

• {{convert|123|psi|Pa}} → 123 pounds per square inch (850,000 Pa)
• {{convert|123|psi|ha}} → 123 pounds per square inch ([convert: unit mismatch])

It is only possible to convert between units that have the same type. For example, psi and Pa are each of type "pressure" so a psi value can be converted to Pa. However, a psi value cannot be converted to a unit of a different type, such as ha (hectare) which has type "area".

Pages with this error are automatically placed in Category:Convert invalid units.[b]

### Ambiguous unit

Mouseover the message to see further information.[a]

• {{convert|21|mpgus|L/km}} → 21 miles per US gallon (0.11 L/km)
• {{convert|21|mpg|L/km}} → 21 mpg[convert: ambiguous unit]
• {{convert|21|USpt|L}} → 21 US pints (9.9 L)
• {{convert|21|pt|L}} → 21 pt[convert: ambiguous unit]

Some unit codes are not supported; using them results in an message indicating that a different unit code should be chosen.

Pages with this error are automatically placed in Category:Convert invalid units.[b]

### Unit invalid here

Mouseover the message to see further information.[a]

• {{convert|123|K|C F}} → 123 K (−150 °C; −238 °F)
• {{convert|123|C F|K}} → 123 C F[convert: unit invalid here]
• {{convert|12345|ft|mi km}} → 12,345 feet (2.3381 mi; 3.763 km)
• {{convert|12345|ft|yd+mi+km}} → 12,345 feet (4,115 yd; 2.3381 mi; 3.763 km)
• {{convert|12345|ft|yd+mi km}} → 12,345 feet ([convert: unit invalid here])

Some units can only be used as outputs. For example "C F" displays a temperature in Celsius and Fahrenheit. Such a unit cannot be used with an input value, because, for example, there is no such temperature as "123 C F". Some output combinations are predefined—"C F" is one example, and "mi km" (miles and kilometres) is another. It is also possible to construct an output combination by joining unit codes with "+". However, individual units have to be specified, and an output combination cannot be used.

Pages with this error are automatically placed in Category:Convert invalid units.[b]

## Notes

1. If the mouse pointer is positioned over the convert message (mouseover), extra information will appear in a popup window.
2. A category is only included in a page if it is in the article or template namespaces.