hand typing

Drafting IEC publications



Writing equations & formulae

Which equation editor to use

It is recommended to use MathType/Wiris for composing formulae in documents. The reason for this preference is that MathType produces consistent and repeatable results that are fit for publishing, even with complex expressions.


MS Word includes a basic equation tool in the Insert tab. However, we recommend to avoid using it because it is not capable of handling complex expressions reliably and because it does not allow to define the style settings required for IEC documents. Formulae composed using Microsoft's tool will be converted to MathType if they need to be edited by IEC staff.


IEC does not accept formulae submitted as:

  • Images or drawings
  • LaTex
  • MathCAD

Contact IEC if you need help composing or editing formulae.


Working with Math Type

To create a new equation, click on the MathType tab in Word, and select Inline or Display from the Insert Equations group. Inline equations are inserted inline with text, Display equations are inserted on a new line.


To edit an existing equation, double-click on it. The MathType workspace opens. To quit the MathType workspace, click anywhere outside of the equation. You will be prompted to save your equation: click "save" in order to save your modified equation.



Configuring how equation elements are displayed

To comply with the IEC requirements, set the parameters in the MathType workspace with the values shown below. This configuration will remain valid during subsequent sessions.


You can set these parameters manually, or you can download this MathType preferences file: IEC equations.eqp. Load this preferences file by clicking on "Equation Preferences" in the MathType tab, select "This document's equation preferences" and click on "Load From MathType Preference File…" (see image below).

Go to the folder where you saved IEC equations.eqp and select the file, click "Open", then "OK".

Note concerning Greek letters: Greek letters that do not represent variable quantities (e.g. pi and delta) are to be formatted in Arial upright. The style “User 1” can be used to accomplish this.


Note concerning superscripts/subscripts: The rules for the formatting of symbols in equations are the same as those for the formatting of symbols in the main text. If a superscript or a subscript contains a symbol representing a variable quantity, that symbol shall be formatted as such with the style “Variable” (in Times New Roman italics).


To set the parameters manually:

1) In the menu bar at the top, select Styles > Define...


2) In the menu bar at the top, select Size > Define...


3) In the menu bar at the top, select Format > Spacing