# PCB Design Calculators

Free, no sign-up PCB design calculators from Flux: a voltage divider calculator and a resistor color code calculator for 4-, 5- and 6-band resistors.

Free and no sign-up needed — handy for quick checks. When you're working on a full board, Flux can handle these calculations for you inside the editor.

### Voltage Divider Calculator

Work in either direction: get the output voltage from a resistor pair, or start from a target voltage and get the resistor values plus the nearest standard E-series parts, along with current and power dissipation.

[Open Calculator](https://www.flux.ai/p/tools/voltage-divider-calculator)

### Resistor Color Code Calculator

Decode 4-band, 5-band and 6-band resistors by setting each color band, and get the resistance, tolerance and temperature coefficient — or go the other way and turn a resistance value into its color code.

[Open Calculator](https://www.flux.ai/p/tools/resistor-color-code-calculator)

### PCB Trace Width Calculator

Size copper for current with IPC-2221: pick an external or internal conductor, enter the current, allowed temperature rise and copper thickness, and get the minimum trace width plus cross-section, resistance, voltage drop and power loss.

[Open Calculator](https://www.flux.ai/p/tools/trace-width-calculator)

### Online Gerber Viewer

Open a Gerber package or ZIP straight in your browser to check copper, solder mask, silkscreen and drill layers, flip between top and bottom views, and isolate a single layer — nothing is uploaded to a server.

[Open Viewer](https://www.flux.ai/p/tools/online-gerber-viewer)

### Via Current Capacity Calculator

Size plated through-hole vias for current with IPC-2221: enter the finished hole diameter, plating thickness and allowed temperature rise, and get the current capacity per via, plus barrel cross-section, voltage drop and power loss.

[Open Calculator](https://www.flux.ai/p/tools/pcb-via-size-calculator)

### PCB Impedance Calculator

Get characteristic or differential impedance for seven trace types — microstrip, embedded microstrip, stripline, asymmetric stripline and edge or broadside coupled pairs — plus propagation delay, capacitance and inductance per inch.

[Open Calculator](https://www.flux.ai/p/tools/pcb-impedance-calculator)