Which Drawings Are in the Wrong Units? Check INSUNITS Across a Folder
Published November 2026 | 74mph Solutions
You attach the site plan as an xref and it comes in 25.4 times too big. Someone's drawing was set to inches in a millimeter project. Now you wonder how many others are.
Units are invisible until something is inserted at the wrong size. A drawing can look perfect while its units are wrong.
UNITS in each one: an afternoon.
Tornado: one column, the odd ones flagged.
What "Units" Means in a Drawing
| Setting | What it controls | Where you see it |
|---|---|---|
| INSUNITS | The drawing's unit for blocks and xrefs inserted into it or from it. When two drawings differ, the insert is scaled by the conversion. | UNITS dialog, Insertion scale |
| MEASUREMENT | Imperial (0) or metric (1) hatch patterns and linetypes | MEASUREMENT at the command line |
| LUNITS, LUPREC | How lengths display: decimal, architectural and so on, and the precision | UNITS dialog, Length |
| LTSCALE | Global linetype scale, usually tied to units and plot scale | LTSCALE at the command line |
None of these scale the geometry. A drawing set to millimeters can still be drawn in inches.
Check One Drawing
Type UNITS and read Insertion scale, or type INSUNITS and read the number: 1 is inches, 2 feet, 4 millimeters, 5 centimeters, 6 meters, and 0 is unitless.
Check Every Drawing at Once With Tornado
Tornado DWG Scanner reads these settings from every drawing in a folder tree with your own AutoCAD, one row per drawing:
- Drawing units: INSUNITS, flagged when the set is mixed. Set Expected to your standard (in, ft, mm, cm, m or km) and every drawing that differs is flagged.
- Measurement system: metric or imperial, with an expected value.
- Linear unit format: LUNITS and LUPREC as a readable format, such as Dec 0.00 or Arch 1/16".
- Linetype scales: LTSCALE and PSLTSCALE, with an expected LTSCALE.
- Drawing extents: the size of what is drawn, with a computed sheet size. A metric sheet with tiny extents is a hint that the geometry was drawn in inches.
Find the odd drawing before it scales your next xref.
Free trial with no time limit. 10 files per run, all checks.
Fix the Settings in One Run With Hurricane
Export the flagged drawings from Tornado as a file list. Tornado finds Hurricane's file-list folder automatically, so the list loads straight into Hurricane's queue. Then one script sets the units on the whole list:
;Millimeter units (INSUNITS 4), metric hatch and linetypes
INSUNITS
4
MEASUREMENT
1
SCALE (25.4 from inches to millimeters), and that is a decision to make drawing by drawing. Run the script on a copy or two first. QSAVE is left out on purpose: Hurricane adds the save to every drawing.Then run the same Tornado report on the same list. When the Flagged view is empty, export it to Excel (the flag colors come with it) for your records.
What You Need
- Tornado: full AutoCAD 2018 or later on Windows (AutoCAD LT is not supported yet). Free trial: no time limit, 10 files per run, all checks.
- Hurricane: AutoCAD (2026 and all prior versions), AutoCAD LT, BricsCAD, IntelliCAD or DraftSight. Free trial: no time limit, no credit card.
- Both are local Windows programs. Your drawings never leave your PC.
FAQ
What is INSUNITS in AutoCAD?
INSUNITS is the drawing's unit for inserting blocks and xrefs: 1 inches, 2 feet, 4 millimeters, 5 centimeters, 6 meters, 0 unitless. Set it in the UNITS dialog under Insertion scale.
Why does my xref or block come in at the wrong size?
The two drawings have different INSUNITS, so AutoCAD scales the insert by the conversion, for example 25.4 from inches to millimeters.
Does changing INSUNITS scale my drawing?
No. It changes the setting only. Geometry drawn in the wrong units needs SCALE as well.
Does this work in AutoCAD LT?
Hurricane works in AutoCAD LT. Tornado needs full AutoCAD 2018 or later for now.
The next xref comes in at the right size, because every drawing in the set agrees.
Try both free. No time limit.
Related: Find Missing Xrefs | Find Missing Fonts | CAD Submittal Checklist | Check and Fix CAD Standards | Tornado features