Wire Gauge (AWG) Calculator
Calculate the correct wire gauge for your application. Get voltage drop, power loss, and current capacity based on AWG standards.
Calculator
How to Use This Calculator
This wire gauge calculator helps you select the correct AWG wire size for your electrical application based on current, length, and acceptable voltage drop.
- Enter Current — The maximum current your circuit will carry
- Enter Wire Length — One-way distance (calculator accounts for round trip)
- Set System Voltage — Your DC or AC RMS voltage
- Set Max Voltage Drop — Typically 3% for branch circuits, 5% total
- Select Material — Copper is standard; aluminum for cost savings
- Click Calculate — Get recommended gauge and detailed specifications
Use the AWG Table tab to browse standard wire gauges and their properties.
Understanding the AWG System
American Wire Gauge (AWG) is the standard wire sizing system used in North America. The gauge number is inversely related to wire diameter — smaller numbers mean larger wires.
Key Relationships
- Every 3 gauges: Wire area doubles (or halves)
- Every 6 gauges: Wire diameter doubles (or halves)
- Every 10 gauges: Resistance changes by factor of 10
Common Wire Gauges
| AWG | Typical Use | Max Current |
|---|---|---|
| 22-24 | Signal wiring, low-power electronics | 0.5-3 A |
| 18-20 | LED strips, small motors, sensors | 5-10 A |
| 14-16 | Automotive, 12V systems, speakers | 15-25 A |
| 10-12 | Branch circuits, appliances | 30-55 A |
| 6-8 | Sub-panels, large appliances | 65-100 A |
| 2-4 | Service entrance, welding | 100-180 A |
Application Guidelines
Automotive and 12V Systems
- Use 3% max voltage drop for optimal performance
- Consider temperature rise in engine compartments
- Use stranded wire for flexibility and vibration resistance
- Always fuse at the source, rated for wire capacity
Solar and Battery Systems
- Low voltage = high current = thick wires needed
- Keep cable runs as short as possible
- Use 2% voltage drop for efficiency
- Consider temperature derating for hot environments
Audio and Speaker Wiring
- Speaker impedance affects current requirements
- Long runs need heavier gauge to prevent damping
- Minimum 16 AWG for runs over 50 feet
- Use oxygen-free copper (OFC) for best conductivity
Household Wiring (NEC Requirements)
- 14 AWG minimum for 15A circuits
- 12 AWG minimum for 20A circuits
- 10 AWG for 30A circuits (dryers, AC)
- Always follow local electrical codes
Safety Guidelines
Important Safety Notes
- Always use wire rated for your application environment
- Never exceed the ampacity rating of a wire
- Use appropriate fuses or breakers at the source
- Consider temperature derating in hot environments
- Follow NEC or local codes for permanent installations
Temperature Derating
Wire ampacity is typically rated at 30°C ambient. For higher temperatures:
- 40°C: Derate to 82% of rated capacity
- 50°C: Derate to 71% of rated capacity
- 60°C: Derate to 58% of rated capacity
Bundling Derating
When multiple wires are bundled together, they cannot dissipate heat as effectively:
- 4-6 conductors: 80% of rated ampacity
- 7-9 conductors: 70% of rated ampacity
- 10+ conductors: 50% of rated ampacity
Frequently Asked Questions
What voltage drop is acceptable?
The NEC recommends no more than 3% voltage drop for branch circuits and 5% total from the service entrance. For sensitive electronics, 2% or less is preferred. 12V systems are more sensitive — even 0.5V drop is over 4%.
Can I use aluminum wire instead of copper?
Yes, but aluminum has about 61% the conductivity of copper, so you need a larger gauge (typically 2 sizes up). Aluminum also requires special connectors rated for aluminum to prevent oxidation and fire hazards.
Why does wire length matter so much?
Voltage drop is proportional to wire length. In DC circuits, you must account for the round-trip distance (out and back), which doubles the effective length. This is why solar and automotive applications often need surprisingly heavy gauge wire.
What's the difference between stranded and solid wire?
Solid wire is easier to terminate and better for permanent installations. Stranded wire is more flexible and resists fatigue from vibration, making it better for automotive, robotics, and portable applications.
Verify Your Component Selections
After calculating your component values, use Schemalyzer to verify your schematic design. Our AI-powered analysis catches common errors and suggests improvements.
Try Free Schematic Review