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How to calibrate your laptop’s battery and fix inaccurate wear info

By Douglas Black , last updated on September 18, 2018

The issue I’ve been coming across recently seems to be mostly with Dell’s XPS line of laptops, though it can certainly affect others: My new XPS 13 9370, XPS 15 9575, and XPS 15 9570 showed 8, 14.5, and 10% battery wear out-of-the-box, respectively (a battery wear of 10% means that the battery is only able to charge to about 90% of its rated capacity).

Normally, batteries will only show this much wear after a year of heavy usage, and it isn’t something you should accept in a new laptop. I realized something was up when every single XPS 15 I checked out new had around 10% battery wear reported, however.

Battery calibration hasn’t been much of a necessity since lithium-ion batteries got so much smarter over the past few years. Thus, even as someone who considers themselves to know quite a bit about notebooks, properly calibrating the battery in my new XPS laptops (showing incorrect wear percentages out of the box) was something I had to do a bit of reading up on combined with some trial and error to get right, and so I thought I would write a brief guide on how to do it right the first time.

Following this protocol, I was able to reduce the reported wear levels significantly to the low single-digits and recover a good deal of battery life.

Checking your battery’s reported wear

Before bothering with a calibration, it’s necessary to check the reported health of your battery. If your battery is new and showing less than 95% of its original capacity then it is probably worth recalibrating.

Go to the Start menu and search “cmd” to show the Command Prompt (PowerShell will do fine as well). Right-click the search result to run your choice of app as an administrator. Copy and paste the following line into the command line: powercfg /batteryreport

The battery health report will be output to the Windows\system32 folder by default.

Copy the directory path and paste it into your favourite web browser to view it. Once it opens, you can scroll down a bit and you should see your battery’s health as a function of design capacity (rated capacity) and full charge capacity (actual amount the battery reports it is able to hold).

After calibration. Before calibration, the full charge capacity was only 87,000 mWh, or less than 90% of advertised.

By doing some quick math you should be able to see how healthy your battery currently is. Technically it is not good to fully charge and discharge a Li-Ion battery often (which is what calibration requires), so if your battery is not new and the wear percentage seems reasonable, it may be best to leave it. If you see only 90% of capacity on a new laptop, however, then this guide will definitely help.

The procedure

Step 1:

First, you will need to let your laptop charge to its “full” capacity. OEMs like Dell and Lenovo allow the user to set charging-thresholds on the battery in order to preserve the battery health (this is a very good practice that I encourage all OEMs to follow). Thus, to charge the laptop fully, you’ll need to find that setting and set your charging threshold temporarily to 100%. On XPS machines, this is done through Dell Power Manager or the BIOS.

You’ll need to set the charging behavior to “Standard” or change the slider manually to 100% to complete the first step. Once this is done, make sure your laptop is plugged-in and allow it to charge completely.

Step 2:

Next, you need to let the battery completely discharge until forced shut-off (not just hibernation). There are a few ways to do this, but my favourite method is the simplest: Restart the laptop in BIOS mode, then go out of the house for the day. With this method, you don’t need to worry about the laptop going to sleep or hibernating as these features are not enabled when viewing the BIOS. Additionally, power-saving states are not enabled for the CPU when in the BIOS either, meaning the laptop will run down significantly faster than it would in Windows under normal usage.

You could also use the laptop normally and let it run down until it automatically hibernates, then leave it in BIOS as described above as well. This requires your turn off all of the sleep and hibernation timers in the Power Options control panel first, however.

Step 3:

WAIT. Do not immediately charge the laptop; be sure the laptop has been sitting cool and unplugged for 3-5 hours before the next step. Failing to perform this step can result in making your reported battery wear worse.

Step 4:

Plug the laptop in and let it charge to maximum uninterrupted. You should be able to use the laptop in Windows at this point, but I let it charge in BIOS out of superstition. When you generate your battery report again, you should (hopefully) see a much higher rated capacity for your new battery.


That’s it! Using this method I was able to reduce my 9575 reporting 14% wear down to 4%, my 9570 reporting 10% down to 3.8%, and my 9370 reporting 8% wear down to 4%, and I hope it fixes the problem for you simply as well. As always, try to practice good battery care to prolong their lives: Keep them cool, don’t run them dry, and don’t charge them to maximum often. If you are interested in reading more about safety and care for Li-Ion batteries, you can check out this guide for further reading.

Did you also get an XPS laptop with double-digit battery wear? Please share your results in the comments.



Based in Hong Kong, Douglas Black is a veteran editor of Notebookcheck, university lecturer, researcher, and writer.


  1. imin

    July 18, 2018 at 11:46 am

    Nice article! But shouldn't Dell at least have a better QC prior to releasing their laptop?

    • Douglas Black

      July 18, 2018 at 11:48 am

      Absolutely — the lack of QC is, imo, one of the main reasons why companies like Apple can exist despite being noncompetitive in almost every other arena. I would guess that whoever has been supplying their batteries is the same company for all 3 XPS machines, thus why they all have incorrect wear/capacities.

  2. Matthias

    August 8, 2018 at 12:12 pm

    worked for me perfectly on my new xps 9570. from 87 to 93mWh.

    If i repeat this process, will i get to 97mWh at some point or is 93 the best result i can get for my battery and it will only get worse from this point?

    • Andrei Girbea

      August 10, 2018 at 2:11 pm

      As far as I know, it shouldn't get worse, so you could try it one more time, but it won't probably do much. 93/97 is not bad though.

      Update: Also see Kirikshi's the reply below.

      • kirikshi

        November 28, 2018 at 2:22 am

        That is not true, as any Li-Ion battery is very susceptible to complete discharge.
        It is said to resist quite low (1-2 dozens) of complete harsh discharges (as in the article) till its completely "dead" in terms of residual capacity. So, this experiment (albeit it can help with the calibration) is not a fortnight trick. No one promised that following complete discharge will damage battery (decrease capacity) less, than it rescales the calibration.
        Another reason not to risk – Li-Ion batteries show thermoelecric effect – voltage of a unified battery depends on temperature. (example: https://www.nature.com/articles/ncomms4942#f1) As a result, if you drop your charge to critical level and afterwards your laptop battery cools down – it goes below critical level, damaging the cell.
        All of this means that the procedure, even if it leads to calibration with winning around 5-10% of capacity, shouldn`t be implemented often (more than 4-5 times for the battery life).

        • Douglas Black

          November 28, 2018 at 5:22 am

          That is correct — I hoped I made it clear in the article not to do this unless your battery should be brand new but is showing unusual wear (such as the case with many Dell laptops).

        • Andrei Girbea

          November 28, 2018 at 1:29 pm

          Thanks, you're right, I was only suggesting performing this one more time. I'll edit the initial reply to make it more clearly.

  3. Will

    September 2, 2018 at 9:23 pm

    Worked great for me! Went from 90% to 96% on a brand new XPS 15 9570. Thank you!!!

  4. hp support

    September 26, 2018 at 2:28 pm

    Turn on the computer and immediately press the F2 key repeatedly, once every second until the HP PC Hardware Diagnostics UEFI menu displays. Click Component Tests in the main menu.

  5. Lacy

    November 10, 2018 at 4:28 pm

    Thanks for this article. I'm here because of my Dell XPS 15 9570, FullHD, 97Wh.
    The first weeks the battery last about 8-10h with my use case which look like this:
    60% Videos/Streams via LAN
    25% Office Work
    10% Music via external speakers
    05% Gaming

    After about ten weeks, the battery only last about 4-6h with the same use case.
    So, I just have done the "cmd" step, and the battery has a "full charged capacity"
    of 77Wh, compared to 97Wh! After ~twelve weeks just 80%! of the capacity is left.

    I hope with the steps the capacity will increase again, if not this was the first
    and last time buying such an expansive notebook from Dell…

    • Lacy

      November 13, 2018 at 12:29 am

      So, after 2.5 days, and about 6.times repeating the steps 1-4,
      the battery is now mostly "healed". From 77Wh to 89Wh in just a short time.

      I also know what one problem was.
      Like with the smartphones-batteries, I thought it would be okay to
      charge my notebook at about 15-20% up to 97-100%. But this notebook
      looks like it does not work with this way of charging.
      But, in my opinion the notebook should handle this kind of charging
      in a better way. I mean, I can not wait everytime to charge up to
      100% and then leave my flat.

      Thank you for this steps, saved my money for a new battery ;).

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