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PCB Trace Width Calculator

(PCB Track Width Talculator)

 

 This PCB track width calculator determines approximations to the ANSI/IPC-D-275 and IPC-2221 design standards for PCB trace / track width.

 This calculator is accurate up to 35A current, up to 400mils of trace width, from 10C to 100C temperature rise, and copper of 0.5oz/ft to 3oz/ft. Outside of this ranges, calculator won't produce accurate results.

PCB trace widths are calculated using following formula;

where:

W  = Minimum required track width in mils
I    = Maximum current in Amps
dT = Maximum allowable temperature rise above ambient in C
h   = Thickness of the copper cladding in oz/ft^2
k   = 0.024 for inner layers and k= 0.048 for outer layers

Input Data
Parameter	Value	Unit
Current through trace ( < 35A )		mA A
Cu Thickness (0.5 to 3oz/ft)		oz/ft mil mm um
Trace length		mm inches cm mil
Maximum voltage		V mV
Ambient temperature		C F
Temperature Rise ( <100C )		C F

Results
Parameter	Internal Tracks	External Tracks	Unit
Required Minimum Trace Width			mil mm um
Required Minimum Track Clearance*			mil mm um
Trace resistance			Ohm mili Ohm
Voltage drop			Volts mili Volts
Power dissipation			Watts mili Watts

 

This calculator uses following constants as inputs.

Resistivity of Copper = 19.2 nano Ohm * meter at 25 C for less than oz Copper

Resistivity of Copper = 18.0 nano Ohm * meter at 25 C for 1oz Copper and over

Temperature Coefficient of Copper (Resistivity)= 0.0039 K^-1

Density of Copper = 8490 kg/m^3

Resistivity of Copper = 19.2 nano Ohm * meter at 25 C used between oz and 1oz Copper. Since these Cu thicknesses for PCBs are non standard, there may be small error with this value.

Note *:

Track clearances are based on IPC-2221A standard and these values are for A7 catagory.

(A7 - External Component lead termination, with conformal coating (any elevation))

Download IPC-2221 standard documents from here.