Checking a quantity before it goes into a bid
14 October 2026
A wrong quantity that looks right is worse than a crash. These are the checks that catch nearly everything, in the order they take time.
1. The scale, every time
The status bar shows the scale for the sheet on screen, for example Scale: 1:50.0 (1 pt = 17.639 mm). Compare it with the drawing's title block before you trust any figure from that sheet.
The commonest error in any take-off is a drawing printed or exported at a different size from the one in the title block. Calibrating on a known dimension rather than trusting the title block is the cure, and it takes ten seconds.
2. The outlier warning
QTac watches each item group and reports a measurement more than three standard deviations from the rest. A slab ten times the size of its neighbours is almost always a mis-click or a wrong scale, not a big slab.
Every warning you accept is written into the Assumptions sheet, so the acceptance is part of the record rather than a decision nobody remembers.
3. The working column
Every row of the Detailed Measurement sheet carries its own arithmetic, for example 108.000 sqm x 0.150 m x 1 nos = 16.200 cum. Read a dozen of them. Rows are live Excel formulas, so a reviewer can change a figure and watch the Summary move.
4. The marked-up PDF
Export it (Ctrl+Shift+E) and lay it beside the dimension sheet. Every shape carries its measurement number and item code, so you can see at a glance what was measured as what, and more usefully, what was not measured at all.
The quickest way to find a missing item: in the View tab, Show / Hide, show only one item at a time and look at the drawing.
What QTac refuses to do
- It will not measure on an uncalibrated sheet.
- It will not export while an item has no quantity, or a warning has not been acknowledged.
- It will not use an item that has not been marked as checked in the item dictionary.