Open the PCB Trace Width, Via Current & Microstrip
Calculate PCB trace width for a given current and temperature rise (IPC-2221), the current a trace can carry, via current capacity and resistance.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
What is the PCB Trace Width, Via Current & Microstrip?
Choosing a trace width should not be guesswork: too narrow and the trace overheats or drops too much voltage, too wide and you waste board space. This calculator uses the IPC-2221 relationship I = k·ΔT^0.44·A^0.725 to find the minimum width for a current, temperature rise, copper weight and layer position (external or internal), and the reverse — the current a given width can carry. It also shows the resistance, voltage drop and power loss over the trace length at your operating temperature, and a practical width with a 25% margin.
Further tabs estimate the current capacity and resistance of a plated via from its hole size and plating thickness, and the characteristic impedance of a microstrip from its width, height, copper thickness and dielectric constant using the IPC-2141 approximation. The IPC-2221 data is conservative for modern boards with copper planes; IPC-2152 and your manufacturer's stack-up tool give more precise figures for critical designs.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
IPC-2221 for external and internal layers, 0.5–3 oz copper.
Maximum current for a chosen width and temperature rise.
Resistance, drop and heat for the actual trace length.
Via capacity/resistance and microstrip Z₀ estimate.
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It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
How it compares
A plain look at this tool next to the usual alternative.
| This maker tool | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What temperature rise should I use?
10 °C is common; 20–30 °C for tolerant designs.
What is 1 oz copper?
35 µm (1.378 mil) thick.
Is IPC-2221 still valid?
It is conservative; IPC-2152 is more accurate.
Is it free?
Yes.
How do I use the PCB Trace Width, Via Current & Microstrip?
1. Pick the tab and enter current, rise and copper weight. 2. Read the minimum width and the practical width with margin. 3. Check the voltage drop and power loss. 4. Use the via and impedance tabs where relevant.
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IPC-2221 trace width and current, via capacity, resistance, voltage drop and microstrip. Free to use.
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