WireSizer - DC Voltage Drop

WireSizer makes it easy to choose the right wire size every time. It's fast, accurate, and intuitive!

Simply set your DC voltage, current, and circuit length with quick flicks of your finger — no keyboard needed! Instantly see the correct wire gauge for your desired voltage drop.

Perfect for boats, RVs, trucks, cars, radios, and other low-voltage DC systems up to 60 VDC. Ideal for both professionals and DIY enthusiasts.

Others agree!

"This app is a joy to use! ...you'll be able to get the right wire gauge to use every time. Nice." - Cruising World Blog

"It is a must have for your electrical toolbox." - i-marineapps

Using properly sized wire is important! Undersized wire can lead to equipment malfunction, or even fire! Oversized wire will add to cost and can be harder to work with. And unlike "online" wire gauge calculators, WireSizer will work wherever or whenever you need it.

After you select your circuit details, WireSizer will automatically calculate the minimum wire size for different percentages of voltage drop under normal or "engine compartment" operating conditions using copper wire. Wire gauge recommendations include commonly available sizes in AWG, SAE and ISO/Metric.

WireSizer allows you to select voltages up to 60 VDC, current up to 500 amps, and total circuit length in feet or meters up to 600 feet (or 200 meters).

Results calculated are for voltage drops between 1 and 20 percent (which you can "flip" through to find the one which is best for your purpose), and wire sizes between 4/0 and 18 gauge AWG and SAE, and 0.75 to 92 mm.

WireSizer will also let you select whether the wire is going to run through an engine compartment or a similarly "hot" environment, is sheathed, bundled, or in conduit, and select the wires insulation rating (60C, 75C, 80C, 90C, 105C, 125C, 200C) to fine tune your results.

And finally, the voltage drop calculation results are compared with the safe current carrying capacity (or "ampacity") of the wire, to make sure the wire suggested is suitable.

WireSizer gauge calculation results meet ABYC E11 specifications (standard requirement for boats, excellent guidelines for other uses) provided you have clean connections, and are using good quality wire. ABYC specifications meet or exceed NEC where applicable, and correspond to ISO/FDIS.

* * * NOT FOR USE WITH AC CIRCUITS * * *

If you have any questions (or complaints!), please email us.

Ad free, and will cost less than the wire scraps you probably throw away at the end of the day.