Cheapest 20TB Hard Drives — Live $/TB Prices

All 20TB drives ranked by $/TB

New vs refurbished at 20TB

At the 20TB capacity tier, the refurbished market typically prices 20-30% below new drive equivalents. Right now, the cheapest new 20TB drive is MDD 20TB SAS 12G 7200RPM Enterprise at $15.50/TB and the cheapest refurbished is WD Ultrastar DC 20TB Renewed at $16.40/TB — a -6% 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.

Best use cases for 20TB drives

Current-generation production deployments where $/TB matters most. 20TB drives are the default choice for new TrueNAS builds, UnRAID arrays, and Synology DS1823+ class deployments.

RAID guidance: RAID 6 with hot spare. Consider splitting large deployments into multiple RAID 6 vdevs (8-drive vdevs over 12-drive) to isolate failure domains and reduce rebuild window risk. Use the RAID Capacity Planner to calculate exact usable capacity for any configuration at this capacity.

Power draw: 20TB enterprise SATA drives typically draw 6-9W active, 4-5W idle. Six 20TB 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 20TB drives, sizing up one tier (24TB or larger) defers the next expansion cycle and typically improves $/TB. Sizing up at this tier is usually justified for new deployments.

Is 20TB the right capacity for you?

20TB is the current sweet spot for $/TB in new enterprise drives. Seagate Exos X20 and WD Ultrastar HC570 deliver the best balance of density, price, and availability across the entire current SATA HDD lineup. Refurbished 20TB pulls are increasingly common from 2022-2023 hyperscale deployments. The default choice for new TrueNAS builds, UnRAID arrays, and Synology DS1823+ class deployments. Best $/TB in new drives at the time of writing.

How much can 20TB store?

Concrete capacity examples for a single 20TB drive, before RAID overhead and assuming typical file sizes:

• Photos at 5MB JPEG average: approximately 4,000,000 images
• RAW photos at 30MB per frame: approximately 666,667 frames
• 1080p movies at 8GB average: approximately 2,500 films
• 4K HDR movies at 60GB average: approximately 333 films
• TV series seasons (1080p, 30GB): approximately 667 seasons
• Lossless music tracks (FLAC, 30MB): approximately 666,667 tracks
• Office documents (200KB avg): approximately 100,000,000 files

Real-world usable capacity in a RAID 6 array is lower than the raw drive capacity — see the RAID section below for usable capacity examples at common drive counts.

20TB in a RAID array

Usable capacity examples for 20TB drives at common deployment sizes, using RAID 5 (single parity, one drive of overhead) and RAID 6 (dual parity, two drives of overhead):

At 20TB per drive, single-parity RAID 5 is no longer safe in production. The probability of an unrecoverable read error during the long rebuild window from a 20TB failed drive is high enough that a second failure during rebuild becomes statistically likely. RAID 6 (dual parity) is mandatory at this capacity — the second parity drive absorbs URE-driven read failures during rebuild and prevents data loss.

Rebuild time for a 20TB drive in a RAID 6 array typically runs 60-100 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.

Power and running cost of 20TB drives

Enterprise 20TB 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 20TB drives delivering 80TB usable in RAID 6 consume the same power as six 4TB drives delivering only 16TB usable — but at 500% of the capacity per watt. For datacenter and homelab deployments where electricity is a meaningful operating cost, sizing up to 20TB 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.

20TB price history and 2026 trends

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. The 20TB capacity has been particularly affected because this tier is heavily consumed by hyperscale AI training storage — drives that previously sold in the spot market at competitive prices are now committed to hyperscale buyers. 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 20TB 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.

Related capacities

Frequently asked questions