The estimated sign (℮) (also referred to as ‘e-mark’) is a mark that sometimes can be found on prepackages in Europe. The e-mark indicates that the prepackages are filled according to the European Directive 76/211/EEC.
The scope of the Directive is limited to prepackages that have a predetermined nominal quantity between 5 g or ml and 10 kg or l, are filled without the purchaser present and of which the quantity of product cannot be altered without opening or destroying the packing material.
The e-mark indicates that:
The tolerable negative error is related to the nominal quantity and varies between 9% on prepackages nominally 50 g or mL or less, to 1.5% on packages nominally 1 kg or L or more. The tolerable error decreases as nominal quantity increases, and is done by alternating intervals where there is a fixed error (and thus over the interval the percentage error decreases) with intervals where there is a percentage error.
The estimated sign looks like a lower-case "e" and its shape is precisely defined by an EU directive. It must be placed in the same field of vison as the nominal quantity. This sign has been added to the Unicode list of characters, just as the symbol for the euro has been, and can be considered a new basic character in a typeface. It is character U+212E (℮).
The e-mark may be printed on prepackages if:
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Error tolerance decreases as nominal quantity increases, by alternating intervals of a given percent error with intervals of a given amount error: these interpolate between the stair-step decreases in percentage error.
Thus, for instance over the interval 50–100, the tolerable error is 4.5 g or ml. At the left end of the interval, this is 4.5/50 = 9% error (as with the interval 5–50), while at the right end of the interval, this is 4.5/100 = 4.5% error (as with the interval 100–200). The factor of 2 reduction in percentage tolerable error (9% to 4.5%) corresponds to the size of the interval (50–100).
| Table of tolerable negative errors | |
|---|---|
| Nominal quantity in g or ml |
Tolerable negative error |
| 5–50 | 9% |
| 50–100 | 4.5 g or ml |
| 100–200 | 4.5% |
| 200–300 | 9 g or ml |
| 300–500 | 3% |
| 500–1000 | 15 g or ml |
| 1000–10000 | 1.5% |
The "℮" symbol is listed in Unicode letterlike symbols and can be invoked in various operating systems as per the table below:
| Apple Macintosh | in Character Palette, search for ESTIMATED SYMBOL[1][2][3] |
| HTML or XML | ℮ or ℮[4] |
| Microsoft Windows | Alt + 212E[5] or, using the Character Map program, seach for estimated symbol. |
| Microsoft Word | U+212e or, use Insert Symbol, choose "Letterlike Symbols": the '℮' symbol is near the end of the second row. |
| OpenOffice.org | In Special Characters, in first row of Letterlike Symbols |
| TeX | \textestimated (requires the textcomp package) |
| Unicode | U+212e |