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Cloud Backup Time Estimator

Find out how long your initial cloud backup will actually take, using your real NBN upload speed, not the advertised download tier. Honest output in days and weeks, not marketing estimates.

This cloud backup time estimator calculates how long an initial or incremental backup will take to upload based on your data size, NBN connection type, and real-world upload speed. Accounts for AU NBN upload constraints, where your download tier does not determine upload speed, and outputs an honest timeline in days and weeks.

AU note: On NBN, your download speed tier does NOT determine your upload speed. NBN 100/20 and NBN 50/20 have the same 20 Mbps upload. Your cloud backup speed is limited by upload, not download.
Enter the total size of your NAS data. 1 TB = 1,000 GB.
Leave at 24h unless your ISP throttles or you need the bandwidth during the day.
Accounts for protocol overhead, TCP windowing, encryption, and ISP congestion. 75% is realistic for most home connections.

Initial Backup Estimate

Time to complete initial backup

Ongoing Incremental Backups

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    NBN Upload Speed Reality: What Cloud Backup Actually Looks Like

    NBN Plan Upload (Mbps) Effective throughput 5 TB backup (days) 10 TB backup (days)
    NBN 25/53–4~0.35 MB/s120–160240–320
    NBN 50/2015–18~1.6 MB/s27–3654–72
    NBN 100/2015–18~1.6 MB/s27–3654–72
    NBN 100/4030–36~3.2 MB/s14–1828–36
    NBN 1000/5038–45~4.0 MB/s11–1422–28

    Assumes 75% efficiency and 24-hour daily upload window. ACCC Measuring Broadband Australia data used as reference for typical upload speeds.

    Why NBN 100 and NBN 50 Have the Same Upload Speed

    This surprises most Australians. NBN tier names like "100/20" and "50/20" describe download/upload in Mbps. The first number is your download tier, the 100 or 50. The second number is your upload tier, in both cases, 20 Mbps.

    This means upgrading from NBN 50/20 to NBN 100/20 will make your downloads faster but won't change your backup speed at all. For cloud backups, you need a plan with a higher upload number: NBN 100/40 gives you 40 Mbps upload, and NBN 1000/50 gives you 50 Mbps upload.

    The reason is infrastructure: NBN was engineered with asymmetric speeds, optimised for streaming and downloads rather than uploads. FTTP (Fibre to the Premises) connections can often be upgraded to symmetrical speeds, but most residential services remain asymmetric. Check with your RSP if you're on FTTP, a symmetric plan may be available.

    AU notes: Upload speed varies by NBN technology type: FTTP typically achieves closer to rated speeds than FTTN or HFC. Backup electricity cost: leaving a 15W NAS uploading 24/7 costs approximately $30–40/year at NSW rates. Use our Power Cost Calculator for your state.

    Frequently Asked Questions

    Why does my cloud backup take so long?
    Upload speed, not download speed, determines backup time. On most Australian NBN plans, upload is 20 Mbps or less, even on a 100 Mbps plan. At 20 Mbps, backing up 10 TB takes roughly 2 months of continuous uploading.
    Can I speed up my cloud backup?
    Upgrade to an NBN plan with faster upload (100/40 or 1000/50), use a provider that accepts physical drive seeding (Backblaze B2), or prioritise backing up critical data first and add bulk data over time.
    Does my backup really run at full speed 24/7?
    No. Real-world throughput is typically 70–80% of your rated upload speed due to protocol overhead, encryption, ISP congestion during peak hours, and your NAS CPU handling the encryption. This calculator uses 75% efficiency by default.
    Should I leave my NAS uploading overnight only?
    Overnight-only uploading doubles your backup time. If speed matters, leave it running 24/7. Your NAS backup software can usually throttle bandwidth during work hours if needed.