PCB DC POWER DELIVERY TOOL

PCB Voltage Drop Calculator

Calculate PCB trace resistance, voltage drop, delivered load voltage, power loss, and design headroom using finished copper geometry, conductor temperature, parallel paths, and optional series resistance.

One-way or round-trip path mm, inch, mil, Celsius, and Fahrenheit Parallel routes and added series resistance
Calculate Voltage Drop Review Validation Practice
DC POWER PATH LOAD-POINT CHECK
ONE-WAY LENGTH L CURRENT I SOURCE LOAD COPPER RESISTANCE OPTIONAL RETURN PATH
SUPPLY 12.00 V
LOAD CURRENT 5.00 A
ESTIMATED DROP 137.7 mV

INTERACTIVE DC ROUTE CHECK

Calculate PCB Trace Voltage Drop and Power Loss

Use finished dimensions and conductor temperature. Results update immediately and compare the calculated loss against your selected voltage-drop limit.

Geometry Units
Temperature Units
Drop Limit Format

POWER PATH INPUTS

Electrical and Copper Geometry

V
A
mm
mm
C
qty
mOhm
%
Path Definition

ACTIVE ROUTE MODEL

One-Way Copper Trace

DC RESISTANCE
VIN
I dV
LOAD
Total Copper Length
100.0 mm
Cross-Section per Path
0.0700 mm2
Current per Path
5.00 A
Resistivity at Temperature
19.273 nOhm m
Layer location is intentionally excluded.

For the same finished length, width, thickness, and temperature, DC copper resistance does not require an external or internal layer multiplier. Layer placement matters for thermal behavior and current capacity, which should be checked separately.

Inputs are within the calculator screening range
ESTIMATED TOTAL VOLTAGE DROP 137.7 mV 1.147% of the 12.00 V supply
DESIGN STATUS Good voltage headroom

Calculated loss is comfortably below the selected limit.

Total Path Resistance 27.532 mOhm
Copper-Only Resistance 27.532 mOhm
Delivered Load Voltage 11.862 V
Total Power Loss 688.31 mW
Delivery Efficiency 98.85%
Current Density per Path 71.43 A/mm2
Allowed Voltage Drop 360.0 mV
Remaining Headroom 222.3 mV
MODEL TYPE Temperature-Corrected Copper DC Resistance

CALCULATION BASIS

Temperature-Corrected Copper Resistance Model

The calculator separates copper resistance from optional added series resistance, then applies Ohm’s law to the complete current path.

01

Copper Cross-Section

A = W x T

Finished trace width and finished copper thickness determine the conductive area of each identical path.

02

Resistance at 20 C

R20 = rho20 x L / A

The model uses copper resistivity of 1.724e-8 ohm meter at 20 C.

03

Temperature Correction

R(T) = R20 x [1 + 0.00393(T - 20)]

Copper resistance is adjusted using the near-room-temperature linear coefficient.

04

Voltage and Power Loss

dV = I x R, P = I2 x R

Total resistance includes the effective parallel copper path plus any entered connector, via, or contact resistance.

Path length matters.

Choose One-Way Conductor when evaluating only the routed power trace. Choose Power and Return when both conductors have the same entered geometry and length. For different return geometry, calculate each segment separately or add the measured return resistance as series resistance.

INPUT QUALITY

Use Finished Geometry and the Real Current Path

Accurate route definition is more important than adding unnecessary decimal places to the output.

Measure the Electrical Length

Enter the actual routed conductor length, including meaningful neck-down sections. Do not substitute straight-line board distance.

Use Finished Copper Geometry

Finished width and thickness may differ from artwork and base foil because of etching, plating, and fabrication compensation.

Use Conductor Temperature

Enter the expected copper temperature, not only room ambient. Copper resistance increases as the conductor becomes hotter.

Add Non-Trace Resistance

Use the optional series-resistance input for connectors, contacts, vias, shunts, or measured return resistance that is not represented by the trace geometry.

RESULT INTERPRETATION

Use the Voltage-Drop Limit as a Design Gate

The status compares calculated loss with the limit you enter. It does not replace regulator tolerance, transient, or thermal analysis.

PASS

Below 70% of the Limit

Useful preliminary headroom remains for geometry tolerance, temperature variation, and unmodeled connections.

REVIEW

70% to 100% of the Limit

The route meets the entered limit but has limited margin. Confirm finished geometry and worst-case current.

FAIL

Above the Entered Limit

Reduce length or current, increase copper cross-section, add parallel paths, or lower series resistance.

ENGINEERING BOUNDARY

What the Calculator Includes and What Hardware Must Verify

Included in the Estimate

  • Finished copper width, thickness, and electrical length
  • Temperature-corrected copper resistivity
  • One-way or matched power-and-return path
  • Equal current sharing across identical parallel paths
  • Optional added series resistance and user-defined drop limit

Verify Outside the Calculator

  • Trace heating, copper spreading, airflow, and enclosure conditions
  • Neck-downs, planes, nonuniform current sharing, and via arrays
  • Regulator tolerance, load transients, ripple, and ground bounce
  • Connector, cable, fuse, shunt, and contact resistance tolerance
  • Worst-case measurement at the actual load point

DC DROP IS ONLY ONE PART OF POWER INTEGRITY

Use the result to screen a route, then validate the complete supply path under real load and temperature conditions.

Engineering Validation Technical Whitepapers Reference Platforms

RELATED ENGINEERING TOOLS

Continue the PCB and System Design Check

Use each calculator for its own engineering decision rather than repeating the same input model across multiple tools.

PCB VOLTAGE DROP FAQ

Practical Questions About PCB Power-Path Loss

Calculate copper loss early, then verify the full rail at the actual load point.

The answers below focus on path length, finished copper, temperature, return paths, parallel conductors, and voltage-drop limits.

Discuss a PCB Power Path
Should PCB voltage drop use one-way or round-trip length?

Use one-way length when checking only the power conductor. Use round-trip when power and return use the same geometry and length. Otherwise model each segment separately.

Does an internal PCB layer have higher DC resistance?

Not when finished copper length, width, thickness, and temperature are identical. Internal placement changes thermal behavior, but it does not justify an arbitrary DC resistance multiplier.

Which copper thickness should I enter?

Use finished copper thickness. Outer-layer plating and fabrication tolerance can make the finished value different from the starting foil weight.

Why does conductor temperature change voltage drop?

Copper resistance rises with temperature. The calculator applies a linear temperature correction using a coefficient of 0.00393 per degree Celsius near room temperature.

How should I include vias and connectors?

Add measured or estimated combined resistance in the Additional Series Resistance field. For complex via arrays, use the dedicated PCB Via Current Calculator first.

Can this calculator replace power-integrity validation?

No. It estimates steady-state DC loss. Final validation should include regulator tolerance, transient behavior, return-path review, thermal testing, and load-point voltage measurement.