How long will it take to update to macOS Big Sur?

Upgrading to a new operating system is always an exciting prospect, but it can also be time-consuming. macOS Big Sur, the latest version of the Mac operating system, offers a host of new features and improvements. However, before upgrading, it’s important to have a realistic understanding of how long the process can take. The time it takes to upgrade to Big Sur depends on several factors, including your Mac’s specs, the size of the update, and the upgrade method you use. In this article, we’ll look at the key factors that affect upgrade times and provide tips for speeding up the process. With some preparation and patience, you can minimize frustration and downtime when transitioning to the latest macOS version.

Download Size of macOS Big Sur

The most basic factor determining Big Sur upgrade time is the size of the installer file that needs to be downloaded. For reference, here are the download sizes for macOS Big Sur:

– macOS Big Sur 11.0: About 12GB
– macOS Big Sur 11.1: About 3GB
– macOS Big Sur 11.2 – 11.6: Between 3GB – 5GB

As you can see, the major 11.0 release of Big Sur is quite large, while the incremental point releases are much smaller downloads. The large 12GB file means the initial upgrade process will be longer than subsequent updates. Once you’ve downloaded the full OS, future upgrades will go much quicker.

Mac Specifications and Performance

Beyond just the download size, the overall speed of your Mac will impact total upgrade time. Here are some key hardware factors to consider:

Processor: Macs with faster processors can install updates more quickly. Models with slower CPUs may experience longer upgrade times.

RAM: Increased RAM also correlates with faster upgrade installation. Aim for at least 8GB RAM if possible.

Storage: Big Sur requires up to 14GB of available storage space for the upgrade. Ensure you have ample free space for fastest performance. An SSD drive will be much quicker than a traditional hard disk drive.

Internet connection: Faster broadband internet speeds allow you to download the installer faster. Make sure you have a reliable, high-speed internet connection before beginning.

Peripheral connections: Disconnecting peripherals and external devices can allow your Mac to focus resources on the OS upgrade.

Use Activity Monitor to check your Mac’s current performance levels if you are unsure about its specifications. Identifying hardware bottlenecks ahead of time allows you to forecast how long your particular machine will need for the Big Sur upgrade process.

Upgrade Method: Automatic Software Update

Now that we’ve looked at the key factors involved, let’s examine how different upgrade methods can impact total upgrade time:

1. Automatic Software Update

The easiest approach is to use the automatic update procedure built into macOS. Your system will automatically detect new updates and download and install them in the background.

However, there are a few drawbacks with this method:

– Your Mac controls the timing and you cannot initiate the upgrade yourself.

– It can take much longer for the automatic updater to detect and install major OS revisions.

– Your Mac will need to restart multiple times to complete stages of the installation.

Still, the automatic process involves minimal effort on your part. Just make sure your Mac is plugged in, connected to the internet, and not in use during installation. Also disable memory-intensive apps like Photoshop that could slow the upgrade.

Due to the large download size and system requirements, expect the automatic Big Sur upgrade to take 3-8 hours total, depending on your Mac’s specs. This accounts for download time, multiple restarts, and file optimization done in the background.

Upgrade Method: Download Full Installer

To gain more control over the Big Sur upgrade process, you can download the full OS installer file from the App Store. Here are the steps and timing estimates:

1. Open the App Store and search for “macOS Big Sur”. Click Download.
2. The 12GB installer file will download to your Applications folder. Download time varies based on internet speeds but expect 1-3 hours to download over a broadband connection.
3. Once downloaded, you can choose when to launch the installer. Make sure you disable antivirus software and close all open apps first.
4. Running the installer will take an additional 30-60 minutes as it optimizes files and completes the upgrade.
5. Your Mac will automatically restart multiple times during installation. After the last restart, you’ll be running macOS Big Sur!

Overall, if you have a sufficiently powerful Mac and fast internet, you can expect the direct download and upgrade process to take approximately 2-5 hours from start to finish.

Upgrade Method: USB Install Drive

Finally, creating a bootable installer drive can provide the fastest upgrade time in certain circumstances. This approach makes sense if you have another Mac available to prepare the drive.

Follow these steps to upgrade using a USB install drive:

1. On another Mac, download the Big Sur installer from the App Store.
2. Insert an empty USB drive with at least 16GB capacity. Format the drive to Mac OS Extended format.
3. Open Terminal and enter the createinstallmedia command to transfer the installer to the USB drive. This takes 5-10 minutes typically.
4. Restart your Mac and hold down the Option key to select the USB drive.
5. Launch the installer from the USB and proceed through the upgrade steps.

Since the data is loaded from the faster USB 3.0 drive, the overall process is generally quicker compared to downloading over internet or network.

Upgrade time with a USB installer drive is approximately 1-2 hours in most cases. This will be even faster if you have an SSD-based USB drive.

Tips to Speed Up Upgrade Time

Beyond just choosing the right installation method, here are some additional tips to help expedite the macOS Big Sur upgrade:

– Close all apps and windows before upgrading – this allows your Mac to focus maximum resources on the OS update.

– Disable or quit any anti-malware/antivirus software during install. They can sometimes conflict or cause slowdowns.

– Make sure you meet minimum system requirements (2GB RAM, 12GB storage) or ideally exceed them for best performance.

– Delete unused files and apps to clear storage space before upgrading.

– Use Activity Monitor to check for any rogue processes hogging CPU in the background.

– Reset NVRAM/SMC beforehand to clear any potential software issues stalling performance.

– Connect your Mac directly to a router via Ethernet cable for fastest download speeds.

– Avoid using your Mac during download/installation – let the upgrade process dedicate your machine’s resources fully.

– Back up your Mac with Time Machine so you can restore data quickly in case of issues.

Following best practices like these can help the upgrade go as quickly and smoothly as possible. The better optimized your system, the less time the install will take.


Upgrading a Mac to the latest operating system is a exciting endeavor that opens up new capabilities and features. However, Big Sur’s large download size means the upgrade process can be lengthy depending on your exact hardware configuration and chosen method. Planning ahead and understanding what factors affect upgrade timing allows you to set accurate expectations. In most cases, expect between 1-8 hours from starting your MacOS Big Sur upgrade to having the latest OS up and running. With some preparation and patience during installation, your Mac will be ready to enjoy all that Big Sur has to offer! Let us know if you have any other questions about optimizing your upgrade process.