Alright, figuring out what wire gauge you need for DC current is fairly simple; anybody can do it. We will show you exactly how to figure out DC wire size by the “back of the napkin” calculation. If you don’t have a napkin, don’t worry. To make things simpler, we have created two very useful resources for DC wire size calculation, namely:
- DC Wire Size Calculators. In the 1st calculator, you input wattage and voltage (Example: 500 watts, 12V), and you get the required AWG or kcmil wire size. In the 2nd calculator, you input the amp draw (Example: “I’m running 50 amp DC current, what size wire do I need?”), and you get the wire gauge for copper and aluminum wires.
- DC Wire Gauge Charts. In the 1st chart, we specify the copper and aluminum wire sizes for 12V, 24V, and 48V voltages and wattages ranging from 1 watt to 5000 watts. In the 2nd chart, we specify the DC wire gauges amp draw ranging from 1 amp to 1000 amps.
Here is a very important note about DC wire sizing:
- Wires don’t care about voltage.
- Wires care only about amps.
With DC current, we usually get these two types of questions regarding the wire sizing:
- “I have a 1500-watt device on a 12V battery. What size wire do I need?” As we see here, we know the wattage (1500W) and voltage (12V). Using the electric power equation, we can calculate the amp draw. When we have the amp draw, we can look at wire ampacity charts, and see which wire can handle that amount of amps.
- “I need a 30 amp wire for a 12V battery. What gauge should I use?” In this case, we already have the amp draw (12V voltage is irrelevant). Now we simply match the amps with the wire that can handle those amps.
How To Calculate The DC Wire Size (2 Examples)
Let’s solve 1 example for each of these situations to illustrate how DC wire sizing is done:
1st Example: Let’s say you have a 1000-watt device you want to run with a 12V DC battery. What size wire do you need? Alright, let’s first use this electric power equation to figure out the amp draw:
Amp Draw = Watts / Volts
Insert 1000 watts and 12 volts like this:
Amp Draw (1000W, 12V DC) = 1000 Watts / 12 Volts = 83.33 Amps
We see that we need a wire that can handle at least 83.33 amps. Now, let’s look at the NEC 310.16 Table here that contains the ampacities of copper and aluminum wires. Here is the screenshot:
As we can see, we can use either 4 AWG copper wire (since it has 85A ampacity) or 2 AWG copper wire (since it has 90A ampacity); both need to have more than 83.33A ampacity.
Note: The conductivity of copper is higher than the conductivity of aluminum; that’s why you will usually need thinner copper wires (lower AWG gauge) than aluminum wires.
2nd Example: Now, let’s imagine that we are looking for a 50 amp wire for a 12V battery. We already have the amp draw; it’s 50 amps. We only need to match that amperage with the correctly sized wires. Again, we check the NEC 310.16 table, and see which wires can handle at least 50 amps (here is the screenshot):
For a 50 amp 12V DC current, we need 8 AWG copper wire (it has a 50A ampacity) or 6 AWG aluminum wire (this one also has a 50A ampacity).
Alright, you can do some of these calculations quite easily, but you have to match the resulting DC amp draw with the wire gauges.
To make things easier, we have programmed 2 calculators that do this calculation automatically, and give you the DC wire size (both for copper and aluminum wires) right away. The 1st calculator solves problems akin to the 1st Example we had (insert wattage and voltage, get wire size), and the 2nd calculator solves problems akin to the 2nd Example we have (insert amps, get wire size).
Very important: Below the calculators, you will also find two charts. Namely, we have calculated DC wire sizes for 1-5000 watt power at 12V, 24V, and 48V, and summarized the results in the 1st Chart. We have also calculated the DC wire sizes for 1-1000 amp services, and summarized the results in the 2nd Chart. These two charts are practically “we have done the math for you” resources you can freely use.
Let’s start with the two calculators:
1st DC Wire Size Calculator (Insert Wattage And Voltage, Get DC Wire Size)
Here is how this calculator works:
Let’s say that you have a 1500-watt heater and want to run it with a 12V battery. This is a DC circuit; what size DC wire do you need? Just slide the wattage slider to ‘1500’ and the voltage slider to ’12’, and you get the result:
1500-watt 12V heater has a 125.00 amp draw. To facilitate this DC current, you need either 1 AWG copper wire (130A ampacity) or 00 (same as 2/0) AWG aluminum wire (135A ampacity).
Here is the 2nd DC wire size calculator where you have known amps:
2nd DC Wire Gauge Calculator (Insert Amps, Get DC Wire Size)
This online DC wire gauge calculator is also easy to use:
Let’s say you are looking for a 150 amp DC wire. The batteries can have 12V, 24V, and 48V voltages; the voltage doesn’t really matter here since we already have the amps. What DC wire size do you need for 150 amps? Just slider the amps slider to ‘150’ and you get the result:
For a 150 DC amp draw, you need either 0 (same as 1/0) AWG copper wire (150A ampacity), or 000 (same as 3/0) AWG aluminum wire (155A ampacity).
Based on these calculators, we have calculated the DC wire sizes for you, and summarized the results in these 2 charts:
1st DC Wire Size Chart For 1-5000W At 12V, 24V, And 48V
| DC Wattage: | DC Wire Size At 12V: | DC Wire Size At 24V: | DC Wire Size At 48V: |
| 1 Watt | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 10 Watts | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 50 Watts | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 100 Watts | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 200 Watts | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 300 Watts | 12 AWG Copper Wire, or 10 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 400 Watts | 10 AWG Copper Wire, or 8 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 500 Watts | 8 AWG Copper Wire, or 6 AWG Aluminum Wire |
12 AWG Copper Wire, or 10 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 600 Watts | 8 AWG Copper Wire, or 6 AWG Aluminum Wire |
12 AWG Copper Wire, or 10 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 700 Watts | 6 AWG Copper Wire, or 4 AWG Aluminum Wire |
10 AWG Copper Wire, or 10 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 800 Watts | 4 AWG Copper Wire, or 3 AWG Aluminum Wire |
10 AWG Copper Wire, or 8 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 900 Watts | 4 AWG Copper Wire, or 3 AWG Aluminum Wire |
8 AWG Copper Wire, or 8 AWG Aluminum Wire |
14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 1000 Watts | 4 AWG Copper Wire, or 2 AWG Aluminum Wire |
8 AWG Copper Wire, or 6 AWG Aluminum Wire |
12 AWG Copper Wire, or 10 AWG Aluminum Wire |
| 1200 Watts | 3 AWG Copper Wire, or 1 AWG Aluminum Wire |
8 AWG Copper Wire, or 6 AWG Aluminum Wire |
12 AWG Copper Wire, or 10 AWG Aluminum Wire |
| 1400 Watts | 1 AWG Copper Wire, or 1/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
10 AWG Copper Wire, or 10 AWG Aluminum Wire |
| 1500 Watts | 1 AWG Copper Wire, or 2/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
10 AWG Copper Wire, or 8 AWG Aluminum Wire |
| 1600 Watts | 1/0 AWG Copper Wire, or 2/0 AWG Aluminum Wire |
4 AWG Copper Wire, or 3 AWG Aluminum Wire |
10 AWG Copper Wire, or 8 AWG Aluminum Wire |
| 1800 Watts | 1/0 AWG Copper Wire, or 3/0 AWG Aluminum Wire |
4 AWG Copper Wire, or 3 AWG Aluminum Wire |
8 AWG Copper Wire, or 8 AWG Aluminum Wire |
| 2000 Watts | 2/0 AWG Copper Wire, or 4/0 AWG Aluminum Wire |
4 AWG Copper Wire, or 2 AWG Aluminum Wire |
8 AWG Copper Wire, or 6 AWG Aluminum Wire |
| 2200 Watts | 3/0 AWG Copper Wire, or 250 kcmil Aluminum Wire |
3 AWG Copper Wire, or 1 AWG Aluminum Wire |
8 AWG Copper Wire, or 6 AWG Aluminum Wire |
| 2400 Watts | 3/0 AWG Copper Wire, or 250 kcmil Aluminum Wire |
3 AWG Copper Wire, or 1 AWG Aluminum Wire |
8 AWG Copper Wire, or 6 AWG Aluminum Wire |
| 2500 Watts | 4/0 AWG Copper Wire, or 300 kcmil Aluminum Wire |
2 AWG Copper Wire, or 1/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
| 2600 Watts | 4/0 AWG Copper Wire, or 300 kcmil Aluminum Wire |
2 AWG Copper Wire, or 1/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
| 2800 Watts | 250 kcmil Copper Wire, or 350 kcmil Aluminum Wire |
1 AWG Copper Wire, or 1/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
| 3000 Watts | 250 kcmil Copper Wire, or 350 kcmil Aluminum Wire |
1 AWG Copper Wire, or 2/0 AWG Aluminum Wire |
6 AWG Copper Wire, or 4 AWG Aluminum Wire |
| 3500 Watts | 350 kcmil Copper Wire, or 500 kcmil Aluminum Wire |
1/0 AWG Copper Wire, or 3/0 AWG Aluminum Wire |
4 AWG Copper Wire, or 3 AWG Aluminum Wire |
| 4000 Watts | 400 kcmil Copper Wire, or 600 kcmil Aluminum Wire |
2/0 AWG Copper Wire, or 4/0 AWG Aluminum Wire |
4 AWG Copper Wire, or 2 AWG Aluminum Wire |
| 4500 Watts | 500 kcmil Copper Wire, or 700 kcmil Aluminum Wire |
3/0 AWG Copper Wire, or 250 kcmil Aluminum Wire |
3 AWG Copper Wire, or 1 AWG Aluminum Wire |
| 5000 Watts | 600 kcmil Copper Wire, or 900 kcmil Aluminum Wire |
4/0 AWG Copper Wire, or 300 kcmil Aluminum Wire |
2 AWG Copper Wire, or 1/0 AWG Aluminum Wire |
Now, if you know the wattage and voltage of your DC circuit, you can just check this chart to see which wire you should be using:
Let’s say you want to run an 800-watt device using a 12V battery. Just look at the chart, and you can see that you should be using:
4 AWG copper wire, or 3 AWG aluminum wire. If you are using higher 24V voltage, you would need thinner wires; namely, both 10 AWG copper wire or 8 AWG aluminum wire can be used.
If you have a 750-watt device on a 48V battery (quadruple the voltage, that means 1/4 of the amperage), you should be using even thinner 14 AWG copper or 12 AWG aluminum wires.
Let’s look at the amps-based chart as well:
2nd DC Wire Gauge Chart For 1-300 Amp Currents
| DC Amps: | DC Wire Size: |
| 1 Amp | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 5 Amps | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 10 Amps | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 15 Amps | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 20 Amps | 14 AWG Copper Wire, or 12 AWG Aluminum Wire |
| 30 Amps | 10 AWG Copper Wire, or 10 AWG Aluminum Wire |
| 40 Amps | 8 AWG Copper Wire, or 8 AWG Aluminum Wire |
| 50 Amps | 8 AWG Copper Wire, or 6 AWG Aluminum Wire |
| 60 Amps | 6 AWG Copper Wire, or 4 AWG Aluminum Wire |
| 70 Amps | 4 AWG Copper Wire, or 3 AWG Aluminum Wire |
| 80 Amps | 4 AWG Copper Wire, or 2 AWG Aluminum Wire |
| 90 Amps | 3 AWG Copper Wire, or 2 AWG Aluminum Wire |
| 100 Amps | 3 AWG Copper Wire, or 1 AWG Aluminum Wire |
| 150 Amps | 1/0 AWG Copper Wire, or 3/0 AWG Aluminum Wire |
| 200 Amps | 3/0 AWG Copper Wire, or 250 kcmil Aluminum Wire |
| 250 Amps | 250 kcmil Copper Wire, or 350 kcmil Aluminum Wire |
| 300 Amps | 350 kcmil Copper Wire, or 500 kcmil Aluminum Wire |
| 350 Amps | 500 kcmil Copper Wire, or 700 kcmil Aluminum Wire |
| 400 Amps | 600 kcmil Copper Wire, or 900 kcmil Aluminum Wire |
| 450 Amps | 700 kcmil Copper Wire, or 1250 kcmil Aluminum Wire |
| 500 Amps | 900 kcmil Copper Wire, or 1500 kcmil Aluminum Wire |
| 600 Amps | 1500 kcmil Copper Wire, or You Need 2 Or More Aluminum Wires |
| 700 Amps | You Need 2 Or More Copper Wires, or You Need 2 Or More Aluminum Wires |
| 800 Amps | You Need 2 Or More Copper Wires, or You Need 2 Or More Aluminum Wires |
| 900 Amps | You Need 2 Or More Copper Wires, or You Need 2 Or More Aluminum Wires |
| 1000 Amps | You Need 2 Or More Copper Wires, or You Need 2 Or More Aluminum Wires |
This chart is pretty self-evident as well. If you know what the amp draw in your DC circuit is, you can immediately tell what wire gauge you should be using.
Example: Let’s say that you want to know what size wire to use for 200 amps DC service. From the chart, you can quickly see that you would need 3/0 AWG copper wire or 250 kcmil AWG aluminum wire for 200A service.
Hopefully, with these two calculators and charts, you can now figure out what size DC wire you need. If you need any help with calculating this, you can turn to us in the comment section below, give us some numbers, and we will help you out.