Why set it before you measure
Every Linear and Area group is created at the drawing's default scale at the moment you create it. Set the scale first and every measurement you draw is right from the start. Set it afterwards and you have to answer a prompt about updating the groups you already drew, and check the result.
The scale is almost always printed in the drawing's title block, for example 1:50 or 1/4" = 1'-0". Match it to a preset. If the title block gives no scale, or the sheet has been re-plotted at an odd size, use Calibrating a Drawing instead.
Where the control is
The scale select is in the header of the takeoff workspace, immediately right of the scale system select and left of Actions:
1 : 100It shows the current preset, or the custom ratio when one is active.
Choosing a preset
- 1
Check the scale system select shows the right system for the drawing (see The Scale System).
- 2
Click the scale select 1 : 100.
- 3
Pick the preset that matches the title block (e.g. 1 : 50). Under Both, the list is grouped under Metric and Architectural headings.
- 4
If the drawing already has Linear or Area groups, answer the Update Existing Groups? prompt.
The presets available depend on the scale system:
| System | Presets, in list order |
|---|---|
| Metric | None, Custom, then 1 : 200, 1 : 150, 1 : 100, 1 : 75, 1 : 50, 1 : 25, 1 : 1 |
| Architectural | None, then 3' = 1', 1' 6" = 1', 1' = 1', 6" = 1', 1-1/2" = 1', 1" = 1', 3/4" = 1', 1/2" = 1', 3/8" = 1', 1/4" = 1', 3/16" = 1', 1/8" = 1', 3/32" = 1', 1/16" = 1', 1/32" = 1', 1/64" = 1', 1/128" = 1' |
| Both | None, Custom, then the metric list under Metric and the imperial list under Architectural |
Most UK layout drawings are at 1 : 50 or 1 : 100; most US floor plans are at 1/4" = 1' or 1/8" = 1'. A quick sanity check after choosing: draw one Linear measurement across a door opening. A standard door reads about 0.90 m or 3' 0". If it reads ten times too big or too small, you have the wrong preset.
None
None switches measuring off for the drawing. Every Linear and Area figure reads zero until you pick a real scale. Use it only when a sheet is deliberately not to scale and you want that to be obvious rather than misleading.
Typing a custom ratio
When the drawing's ratio is not in the list (a 1:125 site plan, say), type it directly. Custom is available under Metric and Both only.
- 1
Click the scale select and choose Custom. The Custom Scale dialog opens.
- 2
Stay on the Manual Entry tab.
- 3
In the field after 1 :, type the second number of the ratio. For 1:125, enter 125. The dialog confirms with Scale: 1 : 125 beneath the field.
- 4
Click Apply Scale, or press Enter.
- 5
If the drawing already has Linear or Area groups, answer the Update Existing Groups? prompt.
Afterwards the scale select shows the ratio you typed, for example 1 : 125, in place of the word Custom. The same dialog has a Draw & Calibrate tab for working the scale out from a known distance; see Calibrating a Drawing.
The "Update Existing Groups?" prompt
Choosing a preset or applying a manual ratio on a drawing that already has Linear or Area groups opens this prompt:
Update Existing Groups?
Would you like to update all existing Linear and Area groups to use the new scale (1:50)?
- Yes, Update All — every Linear and Area group is set to the new scale and its lengths and areas are recalculated. Choose this when the previous scale was simply wrong.
- No, Keep Existing — existing groups keep their own scale; only groups you create from now on use the new one. Choose this when the existing measurements were correct, for example when one group was deliberately given its own scale.
Choosing a preset also clears any calibration on the drawing. If you calibrated against a scale bar and then pick a preset, the calibration factor returns to 1 and the drawing measures at the preset ratio alone.
How the scale is saved
The scale system, the scale and any calibration are saved with the drawing. They are still there when you reopen it, and they survive Actions → Reset Drawing , which clears markers, zones and AoIs but not the scale.
There is no project-wide scale. Set it on each drawing you measure. Drawings you have not yet touched open at the default for your preferred scale system.
Common issues
Measurements are out by a small, consistent amount
The preset is right but the sheet was plotted slightly off, or it was uploaded before ZeroCount read paper sizes. Use Custom → Draw & Calibrate to correct it against a scale bar or a known dimension. See Paper Size and Measurement Accuracy.
One group measures differently from the rest
That group has its own scale. Open its menu and choose Adjust Scale to change it. See Scale on Individual Linear and Area Groups.
Next steps
- Calibrating a Drawing — set the scale from a scale bar or dimension when the ratio is unknown.
- Paper Size and Measurement Accuracy — why the paper size pill matters to every measurement.
- Scale on Individual Linear and Area Groups — give one group a different scale from the drawing.
- Drawing Linear Measurements — start measuring once the scale is set.