Wire Resistance Calculator
Every length of wire has a small resistance that adds up on long runs and heavy loads, and this calculator works it out for you. The resistance equals the material resistivity times the length divided by the cross sectional area. Pick copper, aluminium, silver or gold from the material list to load the correct resistivity, enter the wire length in metres and its cross section in square millimetres, and the tool returns the total resistance of the conductor. This matters for choosing a cable that will not overheat or drop too much voltage, for sizing battery leads, and for understanding losses in long extension runs. Because thicker wire has more area, doubling the cross section roughly halves the resistance, while doubling the length doubles it. Enter your numbers and read the answer instantly. Everything runs locally in your browser, so it is fast and private.
How to use Wire Resistance Calculator
- Select the conductor material, such as copper or aluminium.
- Enter the wire length.
- Enter the cross section area or gauge.
- Read the total resistance of the conductor in ohms.
Frequently asked questions
How is conductor resistance calculated?
It multiplies the material resistivity by the wire length and divides by the cross section area, the standard R equals rho times L over A relationship.
Why does material matter?
Copper and aluminium have different resistivity values, so aluminium of the same size shows noticeably higher resistance, which the tool accounts for by material choice.
Should I use one-way or round-trip length?
Enter the one-way length of the conductor; for a full circuit resistance you would double the length to cover both the feed and return.
What is Wire Resistance Calculator?
Every length of wire has a small resistance that adds up on long runs and heavy loads, and this calculator works it out for you. The resistance equals the material resistivity times the length divided by the cross sectional area.
Is Wire Resistance Calculator free to use?
Yes. Wire Resistance Calculator is completely free, with no sign-up and no usage limits.
Does Wire Resistance Calculator work in a web browser?
Yes. Wire Resistance Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Wire Resistance Calculator?
Yes. Wire Resistance Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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