Returns the given value converted to a number. TONUMBER ("42") TONUMBER ("42") returns 42.

When the sole parameter is a number, it is returned unchanged. When it is a logical value, FALSE is converted to 0 and TRUE is converted to 1.

When the value is a text string, a direct conversion is attempted (meaning that "42.1" is converted to 42.1), and an error is returned if the conversion is unsuccessful (meaning that "test" cannot be converted to a number, nor can "test4"). Spaces surrounding the number are ignored, and the empty text string is converted to 0.

The configured locale is taken into account when converting text strings, meaning that if said locale is German, a decimal comma (",") should be used as a decimal separator. If said locale is Australian English, a decimal point (".") should be used. Thousands separators must not be used and negative numbers must use a leading minus sign ("-").

Scientific notation is supported, meaning that the number may be followed by "e" and an exponent. "6.82e-7", for example, is interpreted as "6.82 times ten to the power of -7," which can be expressed as 6.82 * POWER (10, - 7)6,82 * POWER (10; - 7) in a formula.

Temporal values are converted to sequential serial numbers, which is the representation temporal values use internally. The conversion is exact, meaning that the resulting number can be converted back to the original temporal value using the TOTEMPORAL function.

Colors are converted as though the number is a raw color value. Such a value is a 32-bit number incorporating color components adhering to the ARGB color model. The least significant eight bits represent the blue color component, the next eight bits represent the green color component and the eight following bits represent the red color component. The most significant eight bits represent the alpha value, where a value of 0 means that the color is fully transparent and a value of 255 means that the color is fully opaque.

This function is not commonly supported by spreadsheets.