How To Change Measurement Units In SolidWorks: The Definitive Engineering Guide
Modifying measurement units in SolidWorks requires navigating the status bar unit system menu or the Document Properties dialog box to permanently update parts, assemblies, and drawings. Establishing the correct standard before beginning parametric modeling prevents costly manufacturing errors, tolerance stack-up failures, and material misinterpretations.
Pre-Operation & Planning Checklist
Transitioning between metric and imperial systems—or adjusting precision standards—requires careful coordination across templates and active project files. Unplanned unit switches mid-design often corrupt drawing annotations and break downstream parametric relationships.
- Essential Gear & Tools: SolidWorks 2021 or newer (Standard, Professional, or Premium editions), administrative access to modify corporate file templates, and a fully defined 3D model or blank document.
- Prerequisite Knowledge & Standards: Familiarity with SI (International System of Units) and Imperial (US Customary) standards, understanding of ASME Y14.5 or ISO dimensioning standards, and knowledge of decimal place rounding limits.
- Estimated Budget & Duration: Zero capital investment required; execution takes between 30 seconds for active documents and 5 minutes for custom template updates.
Step-by-Step Procedure to Update Measurement Units
Step 1: Accessing the Status Bar Unit System Menu
Locate the status bar in the bottom-right corner of the SolidWorks interface where the active unit system is displayed (such as MMGS, IPS, or MKS). Click directly on this text indicator to open a quick-selection flyout menu showing all standard presets. Choose your desired standard from the list, including Millimeter Gram Second (MMGS), Inch Pound Second (IPS), Centimeter Gram Second (CGS), or Meter Kilogram Second (MKS).
Pro-Tip: Changing the unit system via the status bar instantly updates the active model view, but it only applies to the current document unless you explicitly save it as a template.
Step 2: Customizing Detailed Units and Precision
Open the comprehensive unit settings by navigating to the top menu bar and selecting Tools, then Options. Click on the Document Properties tab, expand the Units category, and select the specific unit definition you want to modify. Here, you can define custom lengths, angles, mass, and volume measurements independent of the presets. Set your desired decimal places ranging from zero to eight significant digits to match your manufacturing tolerances.
Warning: Altering unit precision in an active drawing does not automatically recalculate custom properties or external equations; always verify your parametric dimensions after tightening decimal tolerances.
Step 3: Modifying Mass Property and Drafting Standards
Within the same Document Properties dialog box, review the dual-dimension options if your engineering drawings require both metric and imperial callouts for international manufacturing. Select your preferred mass unit, such as grams, kilograms, pounds, or slugs, to ensure accurate volumetric and center-of-gravity calculations. Check the radio buttons for angle display formatting to ensure your drafts comply with either degree-minute-second or decimal degree standards. Click OK to commit the changes to your active workspace.
Step 4: Saving Changes as Permanent Document Templates
To prevent the need for manual adjustments in future projects, save your newly configured unit system to your company startup templates. Navigate to File, select Save As, and choose SolidWorks Templates (.prt.sldprt, .asm.sldasm, .drw.slddrw) from the save-as-type dropdown menu. Overwrite your default template file or create a new uniquely named template stored within your designated corporate template directory path.
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SolidWorks Unit System Parameters and Thresholds
| System Identifier | Length Unit | Mass Unit | Time Unit | Typical Application |
|---|---|---|---|---|
| MMGS | Millimeter (mm) | Gram (g) | Second (s) | Precision machine parts, consumer electronics, medical devices |
| IPS | Inch (in) | Pound (lb) | Second (s) | Aerospace components, heavy machinery, US standard manufacturing |
| MKS | Meter (m) | Kilogram (kg) | Second (s) | Large-scale civil structures, automotive chassis design |
| CGS | Centimeter (cm) | Gram (g) | Second (s) | Scientific research, physics modeling, specialized academic design |
Common Site Failures & Field Fixes
- Symptom: Drawings retain old dimensions after changing the part unit system.
- Root Cause: Drawing templates maintain independent unit settings separate from the referenced 3D part or assembly file.
- Actionable Fix: Open the drawing document properties, navigate to the Drafting Standard section, and manually update the unit display settings to match the part file or check the override options.
- Symptom: Mass properties and volume calculations appear orders of magnitude incorrect.
- Root Cause: A unit system switch altered the length scale (e.g., from meters to millimeters), but material density properties were entered under the wrong volumetric ratio.
- Actionable Fix: Re-apply the material from the SolidWorks Material database to force the software to recalculate density values against the current active unit system.
- Symptom: Equations and global variables break or return syntax errors.
- Root Cause: Equations hardcode dimensional suffixes, so changing units implicitly invalidates mathematical expressions referencing specific unit types.
- Actionable Fix: Open the Equations dialog box, review flagged algebraic errors, and update any unit-dependent strings to align with the newly selected measurement framework.
Frequently Asked Questions
Can I set a default unit system for all new SolidWorks files?
Yes, you can establish a permanent default unit system by modifying your system-wide document templates. Open a blank part, assembly, or drawing, configure your desired units in Document Properties, and save the file as a template in your designated file locations folder.
What is the difference between changing units in the status bar versus Document Properties?
The status bar provides a quick toggle between predefined system templates like IPS or MMGS for the active session. Document Properties allows deep customization of decimal precision, angle formatting, mass units, and custom drafting standards.
Why do my imported STEP or IGES files open with the wrong units?
Neutral file formats like STEP and IGES do not always carry strict unit metadata, causing SolidWorks to default to the last used template settings. Always verify and adjust the unit system immediately after importing neutral CAD geometry before adding features.
How do I display dual dimensions (inches and millimeters) on SolidWorks drawings?
Navigate to Tools, Options, Document Properties, and select Dimensions. Under the Dual dimension display settings, check the appropriate box to automatically show secondary bracketed dimensions on all manufacturing drawings.
Master Your CAD Workflow Today
Optimizing your SolidWorks environment with standardized measurement templates eliminates costly fabrication errors and accelerates your design-to-manufacturing pipeline. Explore our advanced technical resources to refine your parametric modeling strategies and elevate your engineering output.
