The cheapest 4TB hard drive in stock right now is the HP 695842-001 4TB SAS 6G at $17.00/TB ($68.00 total, New). 45 of 61 tracked 4TB drives are in stock, with new starting at $17.00/TB and refurbished at $18.35/TB.
Entry capacity for backups and single-drive deployments. The 4TB tier is dominated by older SATA enterprise pulls and consumer NAS drives. Watch for SMR variants in consumer lines — only buy CMR drives if RAID is in your future.
Some 4TB consumer drives use Shingled Magnetic Recording (SMR) which causes catastrophic RAID rebuild failures. WD Red (non-Plus) and certain Seagate Barracuda models at this capacity are SMR — avoid them for any RAID deployment. All enterprise 4TB SATA drives (Seagate Exos, WD Ultrastar) and the WD Red Plus consumer NAS line are CMR. Verify recording technology before purchase.
One 4TB hard drive, in decimal units (1TB = 1,000GB), before file-system and RAID overhead. Each line is a division you can redo; the per-file sizes are our assumptions and say so.
Security cameras, recording continuously: 115 camera-days - 8 cameras for 14 days. The arithmetic: 3.2 Mbps ÷ 8 = 0.4 MB/s × 86,400 s = 34.56 GB per camera-day; 4,000 GB ÷ 34.56 = 115 camera-days. The bitrate is WD's reference figure for one stream (single stream, 1080p, h.265, 25fps), from WD Purple / WD Purple Pro data sheets (footnote 3); the 8-camera count is our example. A camera set to a higher bitrate fills the drive proportionally faster.
Guides for this capacity: fanxiang 4tb for gta 6 · skyhawk ai 32tb vs 24tb · wd purple pro 26tb vs 24tb · seagate exos 25tb vs 24tb · synology hat5320 24tb vs ultrastar hc590 · hpe 26tb vs 24tb · dell 32tb vs 24tb hard drive · dell 24tb sas vs sata · the HDD price forecast · fill a NAS at today's prices
Every listing we track at this size - 41 product pages, including ones with no current offer. Out-of-stock pages carry specs and in-stock alternatives, never a stale price.
At the 4TB capacity tier, the refurbished market typically prices 20-30% below new drive equivalents. Right now, the cheapest new 4TB drive is HP 695842-001 4TB SAS 6G at $17.00/TB and the cheapest refurbished is Seagate Enterprise Capacity 4TB SAS 12G 512n at $18.35/TB — a -8% discount for refurb. For backup repositories, RAID 6 capacity tiers, and any deployment with redundancy, refurbished is the right answer. For primary production storage and single-drive deployments, the new drive premium buys peace of mind through full manufacturer warranty and zero accumulated wear.
Established refurbished resellers like MDD MaxDigitalData source from decommissioned hyperscale datacenters and provide 3-5 year reseller warranties at this capacity. Run smartctl on arrival, deploy in RAID 6 with at least one hot spare, and monitor SMART attributes continuously.
Single-drive external backups, small business document storage, USB-shucked desktop storage. Not ideal for RAID arrays — the rebuild time advantage over larger drives is not worth the $/TB premium.
RAID guidance: RAID 1 mirror for 2-bay deployments. RAID 5 acceptable for 3+ bay arrays. Not large enough for RAID 6 to add meaningful protection over RAID 5. Use the RAID Capacity Planner to calculate exact usable capacity for any configuration at this capacity.
Power draw: 4TB enterprise SATA drives typically draw 6-9W active, 4-5W idle. Six 4TB drives in a NAS array consume approximately 35-55W active — modest by enterprise standards but meaningful for home electricity costs over years of operation.
When to size up: If your projected capacity growth over the next 24 months would exceed the array's usable capacity at 4TB drives, sizing up one tier (8TB or larger) defers the next expansion cycle and typically improves $/TB. Sizing down rarely makes financial sense unless bay count is the binding constraint.
The 4TB tier is appropriate for first-time external backup buyers, laptop primary storage upgrades, and single-drive desktop deployments. It is not a strong RAID candidate — the $/TB premium versus 8TB and above rarely justifies the smaller drive size in a multi-bay enclosure. Critically: 4TB is a capacity range where consumer SMR drives are common (WD Red non-Plus, some Seagate Barracuda models). For any RAID, ZFS, or NAS deployment at 4TB you must explicitly verify the model is CMR before purchasing. The safest 4TB choices are WD Red Plus (CMR), Seagate IronWolf (CMR), Toshiba N300, and any 4TB enterprise SATA (Seagate Exos, WD Ultrastar) — all of which are CMR across the product line.
Usable capacity examples for 4TB drives at common deployment sizes, using RAID 5 (single parity, one drive of overhead) and RAID 6 (dual parity, two drives of overhead):
| Drives | Raw | RAID 5 usable | RAID 6 usable |
|---|---|---|---|
| 4 drives | 16TB | 12TB | 8TB |
| 6 drives | 24TB | 20TB | 16TB |
| 8 drives | 32TB | 28TB | 24TB |
| 10 drives | 40TB | 36TB | 32TB |
| 12 drives | 48TB | 44TB | 40TB |
At 4TB per drive, RAID 5 remains acceptable for non-critical deployments because rebuild windows are short and URE risk is manageable. For production storage, RAID 6 still provides better protection at modest capacity cost.
Rebuild time for a 4TB drive in a RAID 6 array typically runs 12-20 hours at typical hardware-accelerated rebuild speeds (assuming the array is not heavily loaded with production traffic during rebuild). Throughout the rebuild window, the array operates at degraded performance and reduced redundancy. Hot spare drives that automatically begin rebuild on first failure shrink the exposure window to minutes rather than hours. Use the RAID Capacity Planner to model rebuild times for your specific drive count and array configuration.
Enterprise 4TB SATA hard drives typically draw 6-10W during active read/write and 4-5W at idle. For a 6-drive array running 24/7 with mixed activity, expect approximately 35-55W of continuous power draw plus the host system's overhead. At typical US residential electricity rates of $0.16/kWh, a 45W array costs about $63 per year in electricity; at commercial rates of $0.10/kWh, about $39 per year.
Fewer high-capacity drives dramatically reduce power consumption per terabyte stored. Six 4TB drives delivering 16TB usable in RAID 6 consume the same power as six 4TB drives delivering only 16TB usable — but at 100% of the capacity per watt. For datacenter and homelab deployments where electricity is a meaningful operating cost, sizing up to 4TB drives delivers better power efficiency per TB stored alongside the $/TB advantage. The TCO Calculator models the full 5-year power cost for any drive configuration.
Enterprise hard drive prices have risen approximately 46-50% since September 2025, driven by AI infrastructure demand absorbing hyperscale HDD production, US import tariffs adding 10-13% to landed costs, and NAND shortages forcing buyers from SSD to HDD for capacity tiers. Smaller capacity tiers including 4TB have seen more modest 15-30% increases as they are less directly consumed by hyperscale AI workloads. Refurbished supply at this capacity remains ample from older hyperscale decommissions. Read the full analysis in Hard Drive Prices Up 50% in 2026.
Most storage analysts expect elevated pricing to persist through 2026 and into 2027. New NAND capacity takes 2-3 years to qualify and ramp; hyperscale AI buildouts are not expected to moderate before late 2026. For 4TB buyers in particular, the practical procurement advice is to purchase current requirements at today's prices rather than deferring in anticipation of price normalization. Monitor live $/TB on this page and on the cheapest per TB tracker for the current best deal at this capacity.
As of the most recent refresh, the cheapest 4TB hard drive on DatacenterDisk is the HP 695842-001 4TB SAS 6G at $17.00/TB ($68.00 total). Prices update about once a day; check the live table above for the current winner.
4TB is appropriate for single-drive external backups, small business document storage, or as a starting point for first-time NAS buyers. For Plex or production NAS, sizes above 16TB deliver meaningfully better $/TB and longer service life.
Some 4TB consumer drives use SMR (Shingled Magnetic Recording) which is unsuitable for RAID arrays — RAID rebuilds can take days and may fail entirely. All enterprise 4TB SATA drives (Seagate Exos, WD Ultrastar) use CMR. Verify the specific model on the manufacturer's spec sheet before purchasing if you plan to use RAID.
Cheapest new 4TB right now: HP 695842-001 4TB SAS 6G at $17.00/TB with full manufacturer warranty. Cheapest refurbished: Seagate Enterprise Capacity 4TB SAS 12G 512n at $18.35/TB with reseller warranty. Refurbished is appropriate for RAID 6 backup and capacity tiers; new for primary production storage.
Live market shows 4TB drives starting at $17.00/TB ($68.00 total for the cheapest in-stock listing). For new enterprise CMR drives at this capacity, expect $22-26/TB depending on brand and series. The DatacenterDisk live tracker has the most current pricing.
At 4TB capacity, NAS-specific lines are limited. Look for CMR drives only — verify recording technology on the manufacturer spec sheet before purchasing. Seagate IronWolf, WD Red Plus (NOT WD Red), and Toshiba N300 are the safe NAS-branded options.
Want one answer instead of the whole catalogue? Today's verdict at this capacity → names the current best by cost per terabyte, with the criterion and the runner-up.