Thickness:

• 16-gauge: 0.0598 inches (1.52mm)
• 18-gauge: 0.0478 inches (1.21mm)

Strength:

• 16-gauge: Stronger, more rigid, better load-bearing capacity
• 18-gauge: More flexible, easier to form and bend

Common Uses:
16-gauge:

• Heavy-duty appliances
• Structural components
• Vehicle body panels
• Industrial cabinets
• Heavy HVAC ductwork

18-gauge:

• Light commercial applications
• Residential ductwork
• Sheet metal crafts
• Decorative panels
• Light cabinet work

Cost:

• 16-gauge: Higher material cost due to more metal content
• 18-gauge: More economical, approximately 20% less expensive

Workability:

• 16-gauge: Requires more power to cut and form, better for welding
• 18-gauge: Easier to cut and bend, suitable for manual tools