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Unit Conversion in PCB

If you are buying PCB made in China, you may often come across some unit conversion issues? The Chinese PCB factories has their own style in making quotations, now let's review the commonly used unit conversion in PCB industry.

1. Metric System and English System

Metric System include the following unit:

  • dm

  • cm

  • mm

  • um

English System include the following unit:

  • ft

  • ln

  • mil

  • uin

PCB manufacturers often use cm/mm and inch/mil to measure line space/line width

2. Conversion

  • 1dm=10cm

  • 1ft=12in

  • 1cm=10mm

  • 1in=1000mil

  • 1mm=1000um

  • 1mil=1000uin

3. Metric and British mutual convesion

  • 1in=2.54cm=25.4mm=25400um

  • 1mil=25.5um

  • 1mil=0.0254mm

  • 1uin=0.0254um

  • 1mm=39.37mil

  • 1um=39.37uin

4. Copper foil thickness conversion

  • 1oz=35um=1.35mil

  • 2oz=70um=2.7mil

  • 1/2oz=17.5um=0.7mil

  • 1/3oz=11.7um=0.5mil

  • 1/4oz=8.8um=0.35mil

blue circuit board
blue circuit board



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