My laptop specs say :input 19V and 6.3A, That means (120W charger), I hve recently bought a charger because my old charger broke up. So this new charger provides 19.5V with 6.5A (126W) ; That are higher than the laptop's specs. Should i look for another charger that is compatible with my laptop 100% or i should not worry about this problem.


Your laptop's specs translate to: "I need a charger with close to 19V, capable of supplying at least 6.3A. I will take less than 6.3A if my load is low, but never more than 6.3A."

This is perfectly fulfilled by your replacement charger, so you are fine.

Rule of thumb:

  • Voltage +/- 5%
  • Amperage: -0%, +infinity%


There seems to be a discussion about the overvoltage question going on in the comments - let me clarify:

No charger in the world will give a 0.000000% tolerance on the stated voltage, e.g. my HP-branded laptop charger produces between 18.4 (highest load) and 20.9 Volts (idle) while specified for 19.4 Volts. I found this out, while a checked a cheap chinese car charger and used a multimeter to compare it to the original charger.

This is why all devices (including laptops) are designed to handle a +/- tolerance on their respective stated input voltages. Laptops tend to have a very high tolerance, as they have switching power circuits inside them to cater for the many different voltages a laptop internally uses (From ca. 1.4 Volts to ca. 14 Volts)

This implies, that a charger with a small (5%) difference on the nominal voltage is very unlikely to do any harm to the device. And i did call it a rule of thumb because no universal hard limits can be given.

  • 2
    Well, 12V through a 3V bulb is 400%. The answer states within 5%... – djsmiley2k TMW May 14 '18 at 15:51
  • 1
    @Stese You will never find a power supply that delivers exactly the proper voltage in consumer product. It doesnt happen, parts and variables in the manufacturing process makes it impossible. Because of this fluctuation in voltage, consumer products are designed to work within a range above and below specification. You can easily see this for yourself. Take a multimeter and measure the voltage from a variety of power supplies and you see that none of them are exact. – Keltari May 14 '18 at 16:09
  • I've removed my answer and other comments, as I wasn't providing sources... however, i'll point out that since we don't know the laptop is capable of handling an over voltage, (since all we know is that the label says 19v) should we be stating it it will be? I think all that is needed here is to caveat that the user should check with the manufacturer first. – Stese May 14 '18 at 16:13
  • 19
    @LPChip devices will only draw as much current as needed, so amperage is not as important as long at it is higher than rated, but voltage needs to be within a safe range. Most devices are tolerant of voltages within 5 to 10% as mentioned by Eugen, but some may not be. YMMV. Here be dragons, etc. You cannot put 240V against a 24V device and expect it to be okay. – Mokubai May 14 '18 at 16:49
  • 7
    Your 120V (in the US) outlet won't even provide exactly 120V. The US acceptable tolerance range is 108V-126V (or 110V-125V for lighting circuits) – BlueRaja - Danny Pflughoeft May 14 '18 at 20:33

Not the answer you're looking for? Browse other questions tagged or ask your own question.