5 A Trace Width with 1 oz External Copper
Review a Circuit Edge power path: compare minimum copper width, resistive loss and the allowance you will carry into layout.
5 A Trace Width with 1 oz External Copper
Five amperes makes copper loss and local bottlenecks harder to ignore. This preset keeps standard one-ounce copper and an external layer so the main design tradeoff is visible: accepting a wider conductor versus changing the construction. The width relation is nonlinear, so multiplying a one-ampere width by five does not reproduce this result. Use the calculated minimum as a starting requirement and compare the 15 percent margin with available routing space.
Design inputs
01 / CONFIGURECalculation workspace
02 / EXPLOREThis legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating. Results are estimates; confirm critical designs with your fabricator.
How it works · formula & assumptions
I = k × ΔT^0.44 × A^0.725; w = A / t. k = 0.048 external or 0.024 internal; A and t in mil units.
This legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating.
Medium-power distribution on standard copper
Five amperes makes copper loss and local bottlenecks harder to ignore. This preset keeps standard one-ounce copper and an external layer so the main design tradeoff is visible: accepting a wider conductor versus changing the construction. The width relation is nonlinear, so multiplying a one-ampere width by five does not reproduce this result. Use the calculated minimum as a starting requirement and compare the 15 percent margin with available routing space.
Review priorities for this case
Review power entry, protection elements and thermal reliefs as one series path. A short neck-down can become the hottest local point, while a longer wide route can dominate voltage loss. If space is limited, compare two-ounce copper using the main tool and ask the fabricator about minimum finished copper and assembly effects.
Model and limits
I = k × ΔT^0.44 × A^0.725; w = A / t. k = 0.048 external or 0.024 internal; A and t in mil units.
This legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating.
Compare before committing
Change one assumption at a time and save the resulting input set with the board revision. Compare the estimate with the full tool explanation, then check local bottlenecks and manufacturing tolerances. These case values describe one starting scenario; they do not replace the product requirements or the fabricator stackup.
Continue with our calculation methodology, fabrication review checklist and high-speed layout guide. For board-specific support, contact Circuit Edge Technologies.
Frequently asked questions
What does the trace width tool calculate?
Review a Circuit Edge power path: compare minimum copper width, resistive loss and the allowance you will carry into layout. This legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating.
Which formula does this calculator use?
I = k × ΔT^0.44 × A^0.725; w = A / t. k = 0.048 external or 0.024 internal; A and t in mil units. The Methodology page records the model and its limitations so that a design reviewer can reproduce the assumptions.
How should I check the input definitions?
Temperature rise is an increase above the local ambient, not the absolute copper temperature. A board in a sealed enclosure may already be substantially warmer than the room. Enter the ambient near the conductor and decide how much extra heating the surrounding components can tolerate. The resistance calculation uses ambient plus the selected rise, referenced to copper resistivity at 20 °C. This is an assumed operating temperature, not a solved thermal equilibrium.
What is a useful worked example?
At 1 A, 10 °C rise and 1 oz external copper, the required width is approximately 0.301 mm. A 15% margin raises this to approximately 0.346 mm. This example is a starting point for checking units, not a universal production recommendation.
Can I use the result as a fabrication or compliance approval?
This legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating. Obtain the required engineering and manufacturing review before releasing a critical design.
How can I save and share my calculation?
Copy Results includes the inputs, outputs and limitations. CSV provides a local record, while Download PDF creates a local engineering report. Share Link encodes the canonical input values in the URL. Anyone with the link can reproduce that input set.
What should I verify before design release?
Record the calculated minimum and the chosen design width as separate values. Round upward to a sensible CAD rule, then inspect the entire path at that rule. For short pulses, model the waveform and transient heating instead of entering a peak value as if it were continuous current. For sustained high power, evaluate planes, busbars, copper inserts or alternative layer allocation. Measure the prototype at the expected enclosure temperature and airflow.