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LTO archive calculator
How many LTO tapes you need to archive a project, across copies, and how long it takes to write. Capacities are native — compression doesn't help already-compressed video.
LTO generations
| Gen | Native capacity | Native speed | Reads back to |
|---|---|---|---|
| LTO-9 | 18 TB | ~400 MB/s | LTO-8 |
| LTO-8 | 12 TB | ~360 MB/s | LTO-7 |
| LTO-7 | 6 TB | ~300 MB/s | LTO-5/6 |
| LTO-6 | 2.5 TB | ~160 MB/s | LTO-4/5 |
| LTO-5 | 1.5 TB | ~140 MB/s | LTO-3/4 |
Why native capacity, not compressed?
Vendors quote a 2.5:1 "compressed" figure, but video is already compressed, so you effectively get the native capacity. Plan with native numbers.
Best practice
Use LTFS for self-describing, cross-platform restores. Keep 2 tape copies + 1 off-site (3-2-1), verify with checksums after writing, and migrate tapes every ~7–10 years or two LTO generations.
LTO math for people who can't lose the negative
When a show wraps, the camera originals are the negative — and keeping 60 TB of them on spinning drives is a slow-motion loss: hard disks are typically trusted 3–5 years on a shelf, while LTO tape is specified for 15–30 years of archival life. That's why insurers and completion bonds increasingly expect an LTO deliverable at wrap.
The practical numbers: LTO-8 holds 12 TB native, LTO-9 18 TB native, both writing at roughly 300–400 MB/s — so a 60 TB show fits on four LTO-9 tapes and takes on the order of two days of continuous writing per copy. Note the word native: the "45 TB" compressed figures on the box assume 2.5:1 compressible data, and camera media is already compressed, so plan with native capacity only.
This calculator turns a project size into tape count, spanning and write-time estimates, including a verification pass and a second copy — because the 3-2-1 rule applies to archives too: two tapes, stored in different buildings, plus whatever stays on disk.
Why can't I use the compressed capacity on the tape label?
Tape drives compress in hardware, but ProRes, REDCODE, BRAW and EXR are already compressed — they won't shrink further. For video archives, LTO-8 means 12 TB and LTO-9 means 18 TB, full stop.
How long will an LTO archive actually last?
Media is rated 15–30 years stored properly (cool, dry, vertical). The real constraint is drive availability: LTO drives read two generations back, so the standard practice is migrating archives every second generation (~5–7 years) while readers are cheap and plentiful.
What format do I write on the tape?
LTFS is the de-facto standard for film archives: the tape mounts like a drive with self-describing files, readable by any LTFS-capable system without the backup software that wrote it. Proprietary backup formats save a little space and cost you recoverability decades later.