Recommended width
30.76 mil
0.781 mm
Per-inch electricals
- Resistance: 1.601e-2 Ω
- Voltage drop @ 2 A: 0.0320 V
- Power loss: 0.0640 W
For 1 in run
Resistance
1.601e-2 Ω
Voltage drop
0.0320 V
Power loss
0.0640 W
Trace width calculator
Size copper traces that survive your current and thermal targets.
Implements the IPC-2221 method to convert current and ΔT budgets into copper widths, while keeping tabs on resistive losses.
IPC-2221
Formula
10 °C
Temp rise
External layer
Layer
Why temperature rise matters
Lower ΔT limits keep copper cooler but increase required width. Mission-critical rails stay under 10 °C and often choose the conservative internal-layer profile even on external planes.
Quick presets
Input parameters
A
Copper weight
Layer type
Copper cross-section
Dimension lines scale to the computed width and copper thickness.
Copper thickness derives from the selected oz weight (1.378 mil). Because both axes use the same scale, the aspect ratio matches the real board; PNG/JPEG fallbacks are unnecessary.
Area: 42 mil² · Copper thickness 1.38 mil (0.035 mm)
Thermal headroom
ΔT 10 °C
Lower this value to widen the trace and shrink copper heating.
Copper weight comparison
0.5 oz copper
Trace = 61.53 mil / 1.563 mm
1 oz copper
Trace = 30.76 mil / 0.781 mm
2 oz copper
Trace = 15.38 mil / 0.391 mm
3 oz copper
Trace = 10.25 mil / 0.260 mm
4 oz copper
Trace = 7.69 mil / 0.195 mm
Design notes
Last verified Q3'25
- IPC-2221 is conservative—if you need higher density, consult IPC-2152 or your fab's stackup data for refined thermal models.
- Always confirm allowable current with the actual board environment (enclosure airflow, copper pour sharing, nearby heat sources).
- For redundant rails, keep current density below 35 A/mm² to avoid electromigration in high-temp cycles.