The Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) costs $0.0378/GB while the Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 costs $0.0305/GB. Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 offers 19% better value per gigabyte as of July 2026. Both products are available on BuyPerUnit with prices from Amazon, Best Buy, and Newegg.

Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) vs Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 — Which Is Better Value?

Specification Comparison

SpecSeagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D)Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400
BrandSeagateSeagate
Capacity18TB16 TB
$/GB$0.0378$0.0305
Price$680.00$487.29
RetailerNeweggAmazon
CategoryHard Drives (HDD)Hard Drives (HDD)
Subcategoryhddhdd

Price Across Retailers

Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D)

Newegg$0.0378//GB
$680.00Buy

Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400

Amazon$0.0305//GB
$487.29Buy

Which Should You Buy?

Based on current pricing data, the Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 offers better value at $0.0305//GB compared to the Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) at $0.0378//GB — that's roughly 19% less per gigabyte.

The best deal for the Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 is $487.29 at Amazon, while the Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) starts at $680.00 at Newegg.

However, price per gigabyte isn't everything — consider factors like warranty, performance specs, brand reliability, and your specific capacity needs. Check each Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) and Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 product page for detailed specifications and price history.

Frequently Asked Questions

Is Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) or Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 a better deal?

As of July 2026, Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 offers better value at $0.0305//GB compared to Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) at $0.0378//GB. That is approximately 19% better value per gigabyte.

What is the price per GB of Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D)?

The Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) is currently priced at $0.0378/GB ($680.00 for 18TB) at Newegg.

Where can I buy Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 for the cheapest price?

The cheapest price for the Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 is $487.29 at Amazon, which works out to $0.0305/GB.

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