The best cloud backup solutions can help you avoid disastrous data loss. Each service constantly copies your personal data from your computer (or multiple computers) to far-off cloud storage servers that can be reached from anywhere you can get internet access.
This is necessary to have because you can't count on local backup drives to always protect your data. An external backup drive attached to your PC, or as a stand-alone backup device on your home network, may fall victim to the same flood, fire or theft that takes out your computer, leaving you with nothing.
Conscious of this, many businesses and other enterprises rely on "off-site" backups to minimize the threat of physical disasters. Cloud-backup services provide this same peace of mind to consumers. Here's more on the merits of cloud services versus external hard drives as backup solutions.
Each cloud-backup service we've tested — Acronis True Image, Backblaze, Carbonite Safe, CrashPlan for Small Business, IDrive Personal and SpiderOak One — uses industry-standard encryption on their own servers to protect your data.
Each service also lets you encrypt your data with your own private key. But if you lose that key, the service can't help you recover the data.
Top 3 best cloud backup solutions
1. IDrive is the best cloud backup solution right now
IDrive ranks highly on every review due to its great features and fair pricing. The software is available for Windows, macOS, Android and iOS, and there are command-line scripts for Linux machines. Best of all, iDrive currently has an amazing offer for Tom's Guide readers, who can get the 10TB plan for just $3.98 for the first year; that's a massive 95% off.
2. Backblaze is the easiest cloud backup solution
Backblaze is the easiest cloud storage solution to use — just set it and forget it. It has a useful restore-by-mail feature and rapid upload speeds. This is a great choice if you're looking for the best bang for your buck.
3. Acronis True Image is a powerful and versatile option
Acronis True Image, recently renamed as Acronis Cyber Protect Home Office, is the most powerful online-backup solution available for consumers, and now includes antivirus software and ransomware protection.
Some cloud-backup services let you back up operating-system files and applications, while others back up smartphones and tablets. Most can back up files to a local drive, and some even let you share files with other people or provide file-syncing or dead-storage functions.
Because restoring terabytes of lost data can take days, some of these services will express-ship you a hard drive with your recovered data to save time. (IDrive also lets you "seed" an initial backup in the other direction.)
— BackBlaze is ending its USB flash-drive restore option, but you can still get restored files shipped to you on a USB-capable external hard drive.
— IDrive is now offering Tom's Guide readers 95% off its 10TB plan, which comes to $3.98 for the first year.
— Carbonite has slashed prices by 30%, bringing the price of its entry-level subscription plan to $60 per year.
But while some of these services back up an unlimited number of devices, and others give you unlimited online storage, none gives you unlimited space for an unlimited number of devices for a single flat price. That would just be too good to be true.
One last thing: Cloud backup services aren't always the same thing as cloud-based file-syncing services like Dropbox or Microsoft OneDrive. Nor are they exactly like file-archiving services such as Amazon Glacier. We explain the differences between these categories at the end of this buying guide.
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What are the best cloud backup services?
Based on our testing, our Editor's Choice is IDrive ($3.98 for the first year for Tom's Guide readers). It backs up an unlimited number of PCs, Macs, smartphones and tablets for a reasonable price. IDrive is the best choice if you have multiple computers and phones.
Our value pick is Backblaze, which gives you unlimited storage for just $70 per year but backs up only one machine (and an external drive) per subscription. This is the best cloud backup service if you have a single Mac or PC and don't want to worry about the details.
For more on which solution better fits your needs, check out our analysis of whether IDrive or Backblaze is right for you.
Acronis is best for power users, offering a breathtaking assortment of useful features. It's rather complicated and can get expensive for the average home computer user, but it gives you more options than you can possibly think of.
CrashPlan for Small Business technically isn't for home users and costs $10 per month per machine. You'll get an unlimited cloud backup space, extensive security and scheduling options and very fast speeds. However, you won't get mobile-device backups or any drive-shipping options, and CrashPlan's networked-drive backups don't work on Windows.
SpiderOak is famed for its security and encrypts your data with a unique key that only you have. (Don't lose it.) Subscriptions are quite pricey, so get SpiderOak only if protecting your data from prying eyes is your top priority.
Carbonite was once synonymous with cloud-backup software, and it still has a rich feature set. Its consumer offerings seem affordable, but read the fine print: To get anything like iDrive or Backblaze's level of service, you'll have to pay more.
The best cloud backup service you can get today
IDrive offers the most bang for the buck, backing up an unlimited number of machines to either a 5TB or a 10TB ($3.98 for the first year for Tom's Guide readers) limit, which should be enough for most people. It's our Editor's Choice for best cloud backup service.
IDrive's upload speeds are fast, its mobile apps actually back up the devices they run on (and recognize faces in photos for easy tagging), it provides a generous file-syncing option and it even lets you mail in a full drive instead of spending days uploading data.
IDrive also keeps old copies of each file forever, which is handy, but you'll have to mind those storage caps. It also has two-factor authentication, which is an essential feature every online service provider should offer.
Read our full IDrive Personal review.
Backblaze is one of the cheapest cloud-backup solutions, gigabyte for gigabyte, and that's despite a recent price hike. It's definitely the easiest to use — you literally can just set Backblaze and forget it.
We also like the generous restore-by-mail feature and its rapid upload speeds. Backblaze even lets you locate a lost or stolen computer by geolocating the Wi-Fi network it connects to.
But Backblaze is starting to be left behind as competitors add features such as cloud syncing, file sharing and backups of networked drives. It's also not ideal for anyone who has multiple machines to back up, unless you happen to have have nearly unlimited storage needs. In that case, the reasonable yearly cost to back up each machine may be worth multiple Backblaze subscriptions.
Read our full Backblaze review.
Acronis True Image, recently rebranded as Acronis Cyber Protect Home Office, may be the most powerful and versatile online-backup solution available, with a terrific desktop application and an insane number of backup and security options.
It offers mobile-device, external-drive and social-media backups, as well as syncing and sharing options. It will save an image of your primary hard drive — applications, OS and all — to the cloud. It also includes antivirus software, ransomware protection, a vulnerability scanner and a bootable file-restoration tool.
Yet Acronis True Image/CPHO can be the most frustrating of the best cloud backup services, with prices that rapidly ratchet up as you add devices and storage, and weak web and mobile interfaces. But may be the best option if you're a power user or someone who's shopping for antivirus software as well.
Read our full Acronis True Image review.
CrashPlan had the best cloud backup service for consumers until it quit the market in 2017. Its plan for small businesses retains that service's very fast upload and download speeds, and adds business-friendly features such as support for Red Hat and Ubuntu Linux and unlimited (if you want) retention of old versions of files.
Almost everything is customizable, including frequency of backups, retention of deleted files, account security and where to download restored files. CrashPlan supports full-drive-image backups to local drives and backs up Linux/macOS-formatted networked drives. And you get unlimited backup space for unlimited devices as long as you're willing to pay $10 per month per computer.
What you won't get are the consumer-friendly features that made CrashPlan for Home so appealing, such as drive shipping and mobile-device backups. The mobile apps have great security but are pretty bare-bones. CrashPlan for Small Business also consumes a fair amount of system resources during backups, but you can adjust the application settings to reduce that.
Read our full CrashPlan for Small Business review.
SpiderOak was the first online storage (or online-syncing) service to make sure the customer held a private, exclusive encryption key.
Most other cloud storage services now offer the same thing, but SpiderOak also has strong file-sharing and -syncing features, as well as support for unlimited machines and, if you insist, backups of system files and applications.
Yet SpiderOak's storage-space pricing is so high that it's more competitive with Dropbox than it is with IDrive. While its file-restoration speed was amazingly fast, its initial upload speed was glacial.
Read our full SpiderOak One review.
Carbonite offers unlimited storage, which is always nice to have in one of the best cloud backup services. It also has an intuitive user interface that shows you which files have been fully, partly or not backed up.
But you'd better read the fine print, as Carbonite doesn't automatically back up large files, external drives, or any kind of video file on its Basic pricing tier. To get those functions, you'll have to trade up to the Plus or Premium plans, which have features similar to IDrive or Backblaze's basic plans but cost much more. (Carbonite has temporarily slashed prices by 30%, bringing costs a bit closer to those of its rivals.)
Multiple machines are supported on a single account, but there's no volume discount — each additional machine costs as much as the first. Upload speeds are slow. And Carbonite's appealing mobile apps are no longer available, with the company giving no timetable for their return.
Read our full Carbonite Safe review.
How we test the best cloud backup services
We took into consideration several factors: storage costs, ease of file restoration, computer-resource usage, unique features and ease of use and of installation. Upload speed also matters, because while your initial backup happens only once, the backup can take days or even weeks if it's several hundred gigabytes.
We give bonus points to those online backup services that let you mail in a hard drive full of data to start the process or send you one to restore your data.
Our testing and evaluating was done on a 2017 15-inch Apple MacBook Pro booting into Windows 10. Mobile apps were run on a Google Pixel XL 2 running Android 8.1 Oreo. We monitored data-transfer rates on the MacBook with GlassWire, and CPU usage using Windows' built-in Resource Monitor.
Each cloud backup service was tested individually, then uninstalled from both devices before the next test. The test set of files to back up consisted of 16.8GB of documents, photos, videos and music. We uploaded this data to each service's cloud servers, then restored a 1.12GB subset of these files to the laptop.
The testing environment was a home in Middleton, Wisconsin, provisioned by TDS Telecom Extreme 300 Fiber internet service. Internet speeds during testing were typically 280 megabits per second (Mbps) down and 120 Mbps up, according to Speedtest.net.
Online backup vs. online syncing vs. online archiving
An online-syncing service's software creates a cloud-based mirror of a specific set of files or folders on your device, and pushes out identical copies of those files to all of your linked devices so that you can have immediate access to them. Think of the syncing service as the hub on a spoked wheel, with all your linked devices at the ends of the spokes.
Cloud-backup services are simpler. They continuously or periodically copy all or most of the files and folders on your computer to their own cloud servers. Instead of the spoked-wheel diagram of a file-syncing service, an online-backup service would look like a straight line between your machine(s) and the cloud server.
Your data stays on those remote backup servers until you need it, and with luck, you never will. Most cloud-backup services offer generous amounts of storage for a subscription fee that is much cheaper, gigabyte for gigabyte, than an online-syncing service.
Cheapest of all are cloud-archiving services such as Box or Google Cloud. These let you offload files you don't immediately need to online servers, freeing up space on your hard drive.
Cloud-archiving services can be dirt-cheap, sometimes as little as a few pennies per month per gigabyte, but there's often a fee to download files again. (The assumption is that you will never need to download all the archived files.) Backblaze has its own very affordable cloud-storage service called B2.