Free Open Source Backup Software

What Free Actually Means in Backup Software

The word "free" in software has two meanings that are important to distinguish. Free as in cost means you pay nothing for the software license. Free as in freedom (open source) means you can inspect, modify, and redistribute the code. Open source backup tools are free in both senses. You pay nothing, and you get complete access to the source code.

This is different from the "freemium" model used by commercial backup vendors. Tools like Veeam, Acronis, and Carbonite offer free tiers that limit the number of machines, the amount of data, or the features available. If you exceed these limits, you must pay for a license that can run from $50 per year for home use to thousands per year for business use. Open source tools have no such limitations. You can back up as many machines, with as much data, using every available feature, for as long as you want.

The practical cost of running open source backup software comes entirely from storage. You need somewhere to store your backup data, and that storage is never truly free unless you already own it. Understanding storage costs is essential to choosing the most cost-effective backup approach.

Storage Cost Breakdown

The most affordable cloud storage options for backup in 2026 are:

Backblaze B2: $6 per TB per month for storage, $0.01 per GB for downloads. For a typical home user with 500 GB of data, that is about $3 per month. B2 is the most popular cloud storage backend for Restic and BorgBackup (via rclone) users because of its low cost and full S3-compatible API.

Wasabi: $6.99 per TB per month with no egress fees. Wasabi is attractive because you can restore your data without paying download charges, which eliminates the risk of surprise bills during a disaster recovery. The tradeoff is a 90-day minimum storage duration, you pay for at least 90 days even if you delete data sooner.

Hetzner Storage Box: Starts at roughly $4 per TB per month with SSH/SFTP access, making it compatible with BorgBackup out of the box. Hetzner is a popular choice among European users for privacy-conscious backup storage.

Self-hosted storage: If you already have a server, NAS, or even an old computer with available disk space, your storage cost is effectively zero beyond the electricity to run it. A 4 TB external hard drive costs around $80 and lasts for years, making local backup the most cost-effective option for the first copy.

With deduplication, your backup repository is typically 1.1-1.5x the size of your actual data (not the sum of all snapshots). So 1 TB of source data with 30 daily snapshots might only require 1.2-1.5 TB of storage, not 30 TB. This makes cloud backup far more affordable than naive cost calculations would suggest.

Best Free Backup Tools by Use Case

For Personal Computers: Kopia or Duplicati

Home users who want a graphical interface should start with Kopia (for more control) or Duplicati (for maximum simplicity). Both provide point-and-click backup configuration, scheduling, and restoration through a web browser.

Kopia's desktop application (KopiaUI) runs on Windows, macOS, and Linux. It guides you through creating a repository, selecting directories to back up, and setting a schedule. Backup data is encrypted and deduplicated automatically. You can store backups on a local external drive, network share, or any supported cloud provider.

Duplicati focuses on ease of use above all else. Its setup wizard walks through every step, and it supports consumer cloud storage services like Google Drive and OneDrive in addition to standard backup providers. This is convenient because many home users already have cloud storage through their Google or Microsoft accounts.

For Single Servers: Restic or BorgBackup

Server administrators who are comfortable with the command line should use Restic (for cloud backends) or BorgBackup (for SSH backends). Both are mature, well-documented, and designed for unattended operation through cron or systemd timers.

The total cost for a server backup to Backblaze B2 with Restic: $0 for the software, $3-6 per month for storage (assuming 500 GB to 1 TB of source data with deduplication). That is enterprise-grade encrypted, deduplicated backup for the cost of a cup of coffee. See our How to Set Up Automated Backups guide for step-by-step instructions.

For Small Office Networks: UrBackup

UrBackup provides centralized backup management, a web dashboard, and both file and image backup capabilities at zero licensing cost. The server runs on a Linux or Windows machine, and client agents run on all machines being backed up. There is no limit on the number of clients, data volume, or retention period. The only cost is the storage hardware on the server machine. See How to Install UrBackup for the complete setup process.

For Enterprise Environments: Bacula Community Edition

Bacula's community edition is fully functional open source software with no feature restrictions. It supports tape libraries, disk pools, cloud storage, and scales to thousands of clients. The enterprise edition adds a web management interface and vendor support, but the community edition includes all the backup and restoration functionality. For organizations with in-house Linux expertise, Bacula Community provides enterprise-grade backup infrastructure at zero licensing cost.

Hidden Costs and Tradeoffs

While the software is free, there are real costs that organizations should account for when planning an open source backup deployment.

Staff time: Open source tools require more initial setup and configuration than commercial products that come with a polished installer and support team. An administrator familiar with Linux can set up Restic or BorgBackup in an afternoon, but someone learning from scratch should budget a full day for initial deployment and testing. This is a one-time cost that pays for itself within the first month of avoided license fees.

Monitoring: Commercial backup products include dashboards and alerting as part of the package. With open source CLI tools like Restic and BorgBackup, you need to build your own monitoring, which typically means a wrapper script that sends email or webhook notifications on failure. UrBackup and Kopia include built-in monitoring, reducing this overhead.

Support: Open source tools do not come with a vendor support hotline. Support comes from documentation, community forums, and GitHub issues. In practice, the communities around Restic, BorgBackup, and UrBackup are responsive and helpful, but you should be comfortable troubleshooting on your own for urgent issues outside of business hours.

Cloud storage egress fees: Some cloud providers charge for downloading data. Restoring 1 TB from Amazon S3 costs approximately $90 in egress fees. Backblaze B2 charges $0.01 per GB ($10 per TB), and Wasabi charges nothing. Factor in restoration costs when choosing a cloud storage provider, not just the monthly storage rate.

Free vs Paid: When Is Commercial Software Worth It?

Open source backup tools are the right choice for most individuals, small businesses, and technically capable organizations of any size. Commercial backup software earns its price in specific scenarios: when you need vendor-supported disaster recovery with guaranteed response times, when compliance requirements mandate vendor attestation, or when your team lacks the Linux skills to deploy and maintain open source tools.

For everyone else, the combination of a mature open source backup tool (Restic, BorgBackup, Kopia, or UrBackup) with affordable cloud storage (Backblaze B2 or Wasabi) provides the same level of data protection at a fraction of the cost. The tools are battle-tested, actively maintained, and used by millions of individuals and organizations worldwide.