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Electrical calculator

PCB Trace Thermal Calculator

Estimate copper trace I²R power and temperature rise with a board thermal resistance. Runs locally in your browser.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance
Input interpretation
Enter values to calculate.
Result
—
Assurance
Engineering
Declared partition coverage
PASS · 3/3 declared partitions (rise, power, invalid-domain) · Matrix
Known limitations
  • Lumped Rth; default copper ρ
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Trace I²R power and ΔT.
Scope
Uniform copper; lumped Rth
Verification
Engine tested · Source checked · v1.0.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions
Calculation 1.0.0 · CVP protocol 1.0.0-proposed
CVP identity
1/1 property · digest 2f9ad6e41010
Legacy regression
4/4 tests · Production surface contract 4/4
Reference
O1 model · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session.
Supplemental domain review
Internal · Pass · electrical-engineer
Named expert review
Not performed
CVP suite
2/2 golden · 1/1 CVP boundary · 1/1 invalid · 1/1 property · 1/1 cross-interface · 1/1 CVP contract · Manifest
Sources
  • IPC / copper resistivity practice — I²R heating
  • JEDEC / PCB thermal design notes — Lumped Rth rise
Sources
Evidence
2 legacy golden · 1 legacy boundary · legacy regression suite · 2/2 oracle-backed golden · 1/1 invalid · Artifact integrity PASS · CalculatorX electrical review
This calculator CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

ResistanceR = ρ·L/(W·t)
RiseΔT = I²R · Rth
iDefault ρ = copper 1.68e-8 Ω·m. Pairs with IPC Trace Width for sizing.

How to use

1

Enter current and copper geometry

I, length L, width W, and thickness t must be > 0.

2

Enter thermal resistance Rth

Board/ambient path in °C/W as labeled.

3

Read resistance and temperature rise

Electrical R = ρ·L/(W·t); rise follows I²R · Rth style estimates shown on the page.

Example calculations

Common configurations with formula and result.

ϟ

10 A · 0.1 m

W=1mm t=35µm Rth=50

I²R·Rth
ΔT from P·Rth

PCB Trace Thermal calculator specification

Version 1.0.0 · Engine tested · Supplemental domain review · Internal · 2026-08-08

Calculation status

Review policy · Evidence · Reviewed by CalculatorX electrical review (electrical-engineer)

Definition
Trace resistance R = ρ·L/(W·t). Power P = I²R. Temperature rise ΔT = P·Rth for a lumped board thermal resistance.
What it calculates
Trace I²R power and ΔT.
Inputs
  • I_A
  • L_m
  • W_m
  • t_m
  • Rth_C_per_W
Outputs
  • R_ohm
  • P_W
  • dT_C
Formula
ΔT=I²(ρL/Wt)·Rth
Assumptions
  • Uniform copper; lumped Rth
Units
  • A, m, °C/W → °C
Boundary conditions
  • I,L,W,t ≤0 → VALUE_MUST_BE_POSITIVE
Example
10A 0.1m 1mm 35µm
Validation cases

1 published on this page · 4/4 tests · Production surface contract 4/4 · View evidence

  • I=10 L=0.1 W=0.001 t=35e-6 Rth=50 → dT=P·50
Sources
  • IPC / copper resistivity practice — I²R heating
    Supports: R=ρL/A; P=I²R
  • JEDEC / PCB thermal design notes — Lumped Rth rise
    Supports: dT = P·Rth
Last reviewed
2026-08-08
Reviewed by
CalculatorX electrical review (electrical-engineer)
Calculation version
1.0.0

Background

Interpretation and common distinctions.

Estimate PCB copper trace heating.

Supported and not supported

Supported — Power and rise modes · API electrical.pcb.trace_thermal

Not supported — Full IPC-2152 charts, vias as heat pipes

Agent / API notes

Capability id: electrical.pcb.trace_thermal · tool id: pcb-trace-thermal · pin 1.0.0.

Other calculators in this family: Microstrip Impedance Calculator, PCB Differential Impedance Calculator, PCB Trace Width Calculator (IPC-2221), Stripline Impedance Calculator, Via Current Capacity Calculator . Explore all PCB & Signal Integrity.

→ Microstrip Impedance Calculator Compute microstrip characteristic impedance Z0 from W/H/εr, or synthesize width for a target Z0 (zero-thickness IPC-2141 / Wadell–Hammerstad). Runs locally in your browser. › → PCB Differential Impedance Calculator Estimate edge-coupled microstrip differential impedance Zdiff from W, H, S, and εr. Hammerstad/Wadell Z0 plus IPC-2141A-style coupling. Runs locally in your browser. › → PCB Trace Width Calculator (IPC-2221) Size PCB copper traces from current and temperature rise using the classic IPC-2221 I = k·ΔT^0.44·A^0.725 relation for external and internal layers. Runs locally in your browser. › → Stripline Impedance Calculator Estimate symmetric stripline characteristic impedance from W, b, and εr. Extends microstrip / Zdiff. Runs locally in your browser. › → Via Current Capacity Calculator Estimate PCB via ampacity from drill diameter, plating thickness, and temperature rise using the IPC-2221 I = k·ΔT^0.44·A^0.725 relation on the plating cross-section. ›
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Frequently asked questions

Key distinctions behind the calculation.

How to get Rth?

Use a board-level thermal estimate, measurement, or vendor guideline. v1 takes Rth as an input.