Thermal Relief Calculator
Design thermal relief patterns for optimal soldering
Thermal Relief Parameters
Thermal Relief Pattern (Top View)
Analysis Results
Good balance - Easy soldering with adequate current capacity
Opening Ratio
74.5%
Current Capacity
3.5 A
Annular Ring
10.0 mil
Resistance
0.120 mΩ
Voltage Drop
0.120 mV
Gap Width
29.3 mil
Power Loss
0.120 mW
Thermal Relief Design Guidelines
For Better Soldering
- • Use 4 spokes minimum for symmetry
- • Spoke width: 8-12 mil typical
- • Opening ratio: 50-70%
- • Gap width: >8 mil for manufacturability
- • Consider 2 spokes for hand soldering
For High Current
- • Use wider spokes: 15-20+ mil
- • Increase spoke count to 6 or 8
- • Direct connect for very high current
- • Consider thicker copper (2+ oz)
- • Multiple vias for power distribution
Thermal reliefs isolate pads from copper planes, preventing heat sink effects during soldering. Without thermal relief, large planes can absorb heat too quickly for proper solder joints.
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