Compendium of Design

A Body of Knowledge
Learn from those who designed before you.

Lettering and Numbers

The clarity, style, spacing and size of lettering and numerals are vital to instrumental drawings as they ensure that each notation can be read and interpreted without mistake or uncertainty. You should take your time to draw each letter or numeral and practice your lettering skills as often as possible to become consistent in reproducing each letter or number with precision.

Making sense of your writing
Using your normal handwriting style, write down the notation below.


Underneath your normal handwritten notation, rewrite the notation using the neatest handwriting you can write using capital letters only.
Pass your writing onto someone else in the room. Look at the copy you receive in return, which version is easier to read and understand?
• Write down a small sentence with more than 5 words but mix up the letters of each word leaving only the first and last letters in the correct place.
• Write down 5 large numbers with each number containing at least 4 numbers but mix up the number so that only the first and last of each of the larger numbers is in the correct space. Remember the order of the original numbers you chose.
• Pass your sentence and numbers to someone else in the class and get them to read back the sentence and numbers.

What do you notice?
Was the person able to still read the sentence but not the numbers?
When you make notations on instrumental drawings you will need to ensure that all lettering and numerals adhere to the following standards;


Letters and numerals must be drawn legibly, with a consistent style, spacing and size, particularly numerals as unlike letters, numbers rarely fall into self-identifying patterns. This causes numbers to be read individually whereas the letters within a word are automatically decoded and rearranged by your brain.

Spacing of letters

The figures below show the suggested styles which letters and numerals should be drawn. For clarity only capital letters should be used.


The following character heights are suggested for lettering and numerals, 2.5, 3.5, 5, 7, 10, 14, or 20mm. All lettering and numerals used for titles and drawing numbers should be twice the size of dimensions and notes. Characters used for dimensions and notes should not be any smaller than 3.5mm in height for A0 sheets and 2.5mm for small A4 series sheets

All notes and captions should be positioned so that they can be read in the same direction as the title block. Use larger characters to draw attention to notes or captions. Do not underline as this has now become the international standard for hyperlinks and web references.