Plan Annotation Scale Calculator
Computes legible plotted text height for a given drawing scale and model-size annotation.
Enter Values
Minimum 0
How to use this calculator
- Enter the height the text prints at on paper (mm) and the plan scale (1:N).
- Read the real-world (ground / model) height that text represents, and whether it's legible.
- Or enter a required ground height to find the plotted height to use.
How it works
Text on a scaled plan represents a real-world size: ground height = plotted height × the scale denominator. At 1:500, 2 mm of text is 1.0 m on the ground.
Keep plotted text large enough to read in print — roughly 1.8–2.5 mm or more. This is the model-to-paper relationship CAD calls the annotation scale.
Worked example
2.5 mm text at 1:500. Ground/model height = 2.5 × 500 ÷ 1000 = 1.25 m, and 2.5 mm plotted is comfortably legible.
Frequently asked questions
Why does my CAD text look the wrong size when plotted?
Because text drawn in model space scales with the drawing. Set the text height to the plotted size you want times the scale denominator (or use the CAD annotation-scale feature) so it prints at a readable size.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
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Cite this tool
Zerdly. (2026). Plan Annotation Scale Calculator. Retrieved from https://www.zerdly.com/tools/plan-annotation-scale-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.