How to Use Wire Size and Voltage Drop Calculator (AWG) Online for Free: Step-by-Step Guide
Calculate the voltage drop of a copper or aluminium wire and the smallest AWG size that stays under 3%. Free, private and no sign-up.
How to Use Wire Size and Voltage Drop Calculator (AWG) Online for Free
Calculate the voltage drop of a copper or aluminium wire and the smallest AWG size that stays under 3%. This guide shows what Wire Size and Voltage Drop Calculator (AWG) does, how to use it step by step, what to watch out for, and which related tools on shobfree.com can help next.
Quick answer
Open Wire Size and Voltage Drop Calculator (AWG), type your numbers or pick the options you need, check the result that appears, and then use it. Wire Size and Voltage Drop Calculator (AWG) is free, needs no account and runs in your browser, so what you type or add stays on your device.
What Wire Size and Voltage Drop Calculator (AWG) does
- Calculate the voltage drop of a copper or aluminium wire and the smallest AWG size that stays under 3%.
- Choose the AWG size, enter the current in amps, the one-way length in feet and the supply voltage.
- The calculator gives the resistance, the voltage drop in volts and percent, the voltage at the load and the smallest wire size that keeps the drop under 3%.
Choose the AWG size, enter the current in amps, the one-way length in feet and the supply voltage. The calculator gives the resistance, the voltage drop in volts and percent, the voltage at the load and the smallest wire size that keeps the drop under 3%.
How to use Wire Size and Voltage Drop Calculator (AWG), step by step
- Fill in the boxes. Type your numbers or pick the options you need.
- See the result. The answer updates right away as you change a value.
- Use it. Copy the result or note it down. Nothing is sent anywhere.
These three steps are the same on a phone and on a computer. If something looks wrong, change one setting and look at the result again; Wire Size and Voltage Drop Calculator (AWG) updates as you go.
A worked example
A 100 ft run of 10 AWG copper carrying 20 A at 120 V has a resistance of 0.999 Ω per 1,000 ft, a drop of 4.0 V (3.33%) and 116 V at the load. That is above 3%, so 8 AWG (2.1%) is the smallest size that works.
Tips for a good result
- Change one value at a time, so you can see which input moves the result.
- Double-check the units and the currency or period before you trust a number.
- Treat the result as an estimate and confirm important figures with the official source.
- Run a best case and a worst case, then keep both numbers for your planning.
Who is this for?
Wire Size and Voltage Drop Calculator (AWG) is useful for anyone who needs calculate the voltage drop of a copper or aluminium wire and the smallest AWG size that stays under 3% without installing software or paying for a subscription. Students, freelancers, office staff and small-business owners use tools like this for quick, one-off jobs where a full application would be too much.
Frequently asked questions
Why twice the length?
Current flows out and back, so the circuit is twice the one-way distance.
What drop is acceptable?
About 3% for branch circuits and 5% overall.
Is aluminium different?
It has higher resistance, so it needs a larger size for the same drop.
Does it check ampacity?
No. Check the wire's current rating separately.
Do I need to create an account to use Wire Size and Voltage Drop Calculator (AWG)?
No. Open the page and start. There is no sign-up, no email and no payment.
Can I use Wire Size and Voltage Drop Calculator (AWG) on my phone?
Yes. The page adapts to small screens, and everything runs in your phone's browser, so the same steps work on a laptop or a phone.
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Privacy
Wire Size and Voltage Drop Calculator (AWG) works inside your browser. Your files, text and numbers are not uploaded to a server, and there is nothing to delete afterwards.
