Wire Section Calculator & Converter
AWG to mm² Cable Size Calculator
This AWG to mm² calculator helps you convert American Wire Gauge sizes into metric cable sections, compare conductor diameters and determine the cable size required for a 12V, 24V or 48V electrical installation.
AWG is commonly used in North America, while cable sizes in Europe are generally expressed as conductor cross-sectional area in square millimetres (mm²). Because the two systems do not use the same progression, a direct conversion is useful when selecting marine electrical cables, terminals, circuit breakers, relays and other DC components.
How to use the AWG to mm² calculator
- Select an AWG size — the calculator displays the corresponding cable section in mm² and approximate conductor diameter.
- Enter a conductor diameter — the cross-sectional area is calculated automatically and the nearest standard AWG size is shown.
- Enter a cable section in mm² — the calculator finds the closest standard AWG equivalent.
AWG versus mm² cable sizes
American Wire Gauge works in the opposite direction to what may initially seem intuitive: the smaller the AWG number, the larger the conductor. For example, AWG 10 is larger than AWG 16, while 2/0 AWG is considerably larger again.
Metric cable sizes are simpler to compare because the value directly represents the conductor cross-sectional area. A 10 mm² cable therefore has a larger conductor than a 6 mm² cable.
Wire section calculator
The wire section calculator below estimates the conductor size required for an electrical load according to system voltage, current or wattage and total cable run length, using a maximum voltage drop of 3%.
For DC electrical systems, cable length is particularly important. A longer cable has greater electrical resistance, which can increase losses and reduce the voltage available at the equipment.
Measure the complete cable run
When calculating cable length, consider the complete electrical path between the power source and the load. In a typical DC circuit this includes both the positive and negative conductors.
For example, if a device is located 3 metres from the battery and requires a 3 metre positive cable and a 3 metre negative cable, the complete conductor run is 6 metres.
12V, 24V and 48V marine electrical systems
Cable sizing is especially important on boats because many onboard systems operate at relatively low DC voltages. At the same power level, a 12V installation carries more current than a 24V or 48V installation and may therefore require a larger conductor.
This applies to equipment such as bilge pumps, navigation lights, electric winches, battery switches, relays, USB chargers, electric outboards and other high-current marine equipment.
Copper cable and operating conditions
The calculator is intended for copper conductors. Actual cable requirements can vary depending on ambient temperature, installation method, insulation type, continuous current, bundled cables and the acceptable voltage drop for the connected equipment.
For demanding marine installations and continuous high-current loads, selecting the next larger standard cable size is often preferable to operating close to the theoretical minimum.
AWG to mm² reference table
The calculator is intended for copper conductors and uses a maximum voltage drop of 3%. Actual cable requirements can vary depending on ambient temperature, installation method, insulation type, continuous current and bundled cables.
Use the tools below to convert AWG and mm² cable sizes and compare the conductor section required for your electrical installation.
