Does Cable Length Affect Charging Speed? Learn the Calculation.

One of the most common questions is whether the cable length affects charging speed. In this article, we will answer this question and provide some other tips on how to charge your device faster.

Let’s summarise the main points:

The length of the cable can affect the charging speed. The longer the cable, the more resistance it will have to charge your device. The shorter the cable, the less resistance it will have and thus a faster charge.

But how? 

Does Cable Length Affect Charging Speed?

does cable length affect charging speed

Are you wondering if the length of your cable affects charging speed? The cable length does affect the charging speed, but there are exceptions. So, let’s explore the matter in detail.

Relationship between cable length & charging speed

The relationship between cable length and charging speed is that the longer the cable, the slower the charging speed. That’s because, as a current travels through a wire, it decreases power. And science says it’s due to the resistance of the cable expressed in the following formula.

Cable length charging speed

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So, what does this formula mean? Resistivity measures how difficult it is to transmit an electric current through a material. The higher the resistivity, the more difficult it becomes to send an electric current.

The resistance of a wire is proportional to its length. This means that for every doubling in size, the resistance increases. The charging speed also decreases with increased cable length.

What length of charging cable should I use?

It also means the charging time of your device depends on its cable length and resistivity. If you’re using a low-resistance cable, then you’ll charge your device faster. It’s because there will be less resistance for the current to flow through.

So, in our case, a cable’s resistivity measures the material’s ability to resist the flow of electric current. The unit of measurement for resistivity is ohm-meters (Ω). A small change in length can significantly affect the charging speed.

The longer your cable is, the slower it will transfer power because there is more resistance in the wire. As a result, electrons in the cable don’t flow freely as they bump into the conductor’s atoms or ions. It disturbs the current flow, leading to energy loss and opposition to the passage of a current through a conductor. 

A longer cable has more collisions than a shorter cable. If you use a long cord to charge your phone, it’ll take much longer than if you used a shorter one. For example, a one-meter cord has less resistance than a two-meter cord. 

The longer cable delivers a few amperes ( electric current) to your device due to high resistance caused by more collisions between the metal ions and the moving electrons.

But there are some exceptions.

What role do the cable’s thickness and quality play in the charging speed?

So far, we have established that the cable’s length can affect the charging speed. However, its resistance will be low if you have a top-quality cable with chunky wires. The electric current will travel faster from the charger to your phone. 

Less resistance means that there’s increased energy. The supplied power to your device will go up.

Also, the cross-sectional area of the cable will influence the resistance and the charging speed. The larger the cross-sectional area or cord thickness, the less resistance. A thinner cord will have lots of resistance, leading to high energy loss. 

does cable length affect charging speed

And in the USA, the cable’s thickness is measured by a gauge. A thicker wire has a lower gauge, and a higher gauge means the wire is slimmer. Therefore, higher gauge cables have more resistance than lower gauge wires. So, you’re better off with a sturdy and high-quality cable.

Another cable feature that impacts charging is the material it’s made of—wire resistance doubles from silver to copper, gold, and aluminum. Silver is the least-resistant metal. Copper is the primary material for USB and charger cords because it’s cost-effective.

What about temperature? It also affects your cable’s resistance. If you’re juicing your phone where the temperature is pretty high, resistance will be higher than in a place with a low temperature. As a result, your device will charge slowly.

So, what’s the verdict? Does cable length affect charging speed? Yes, but other factors like thickness, quality, temperature, and the product’s material influence the charging rate.

What Length of Charging Cable Should I Use?

First, you should use the cable or charger that came together with your phone. It’s the most recommended cord that has the correct length.

But how can you use regular USB cables if you want a longer cable to extend to other positions in your office or home? 

What are the recommended lengths if you want to use an extension? The most common USB cable is the 2.0 and the latest 3.0./3.1. It’s vital to know the cables’  maximum length before you connect them to an extension to make a longer cord.

Maximum length of a USB 2.0 cable

If you want to connect to USB 2.0 devices (Hi-Speed or Full Speed) ), the maximum cable length should be 5 meters or nearly 16 feet and 5 inches. This means you can’t connect extension cords that exceed 5 meters, even if you want to extend your charging cable. You won’t get enough power. 

Maximum length of USB 3.0 / USB 3.1 cable

The latest USB 3.0 and 3.1 cords don’t have specific limitations regarding the maximum length between devices (SuperSpeed or SuperSpeed+). However, the ideal cable length should be 3 meters ( 9 feet and 10 inches) to get full power. The cable’s quality will also determine its charging speed.

Note the following concerning the length of charging cable you need to use.

  • Use the charger for your smartphone or laptop you received at the time of purchase.
  • If you need to replace the cable, get one with the same power rating and quality. Buy a USB-IF-certified cable as it meets high standards of quality. Or opt for Qualcomm Quick Charge cables. 
  • Consider the USB 2.0 and USB 3.0/3.1 ideal cable lengths if you want to extend your charging cords to other rooms.
  • Avoid using shoddy cables to power up your devices. It may look like they’re charging, but they’re taking ages and delivering little power.
  • The higher the quality of your cables, the better the charging speed. So, you don’t have to worry about cable length.


Do longer cables charge slower?

Yes, a longer cable results in a voltage drop. But the critical factor is the gauge of the wire. The thicker it is, the more efficient it becomes at transmitting power.

Other factors like wire material and temperature have less impact on the charging speed. That’s because USB cables are made of copper. As a result, the temperature in your charging environment won’t change whether you use a long or short cord.

And USB makers use lower gauge wire in long cables to prevent a voltage drop.

Does a shorter cable charge faster?

Yes, they’ve got less resistance. So, shorter cables can deliver power faster. But it also depends on the thickness and quality of the cord.

Are longer charging cables better?

No, if they’re substandard quality and slimmer. But modern USB cables use top-quality material to minimize the loss of energy. So, even if they’re longer, the wires can still perform efficiently.

Avoid buying cables with no-name brands. Always get USB-FI-certified cords.

Does a longer wire take longer to charge?

Yes, it depends. For example, lower gauge wires can charge faster, even if they’re longer. So, quality matters more than length. 

Brett Jones
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