The WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP costs $0.0469/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 35% better value per gigabyte as of July 2026. Both products are available on BuyPerUnit with prices from Amazon, Best Buy, and Newegg.
WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP 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
| Spec | WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP | Seagate Expansion Desktop 16TB External Hard Drive – USB 3.0, 3.5" HDD for Windows & Mac, Plug-and-Play Backup Storage - STKP16000400 |
|---|---|---|
| Brand | Western Digital | Seagate |
| Capacity | 18TB | 16 TB |
| $/GB | $0.0469 | $0.0305 |
| Price | $844.99 | $487.28 |
| Retailer | Newegg | Amazon |
| Category | Hard Drives (HDD) | Hard Drives (HDD) |
| Subcategory | hdd | hdd |
Price Across Retailers
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 WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP at $0.0469//GB — that's roughly 35% 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 $487.28 at Amazon, while the WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP starts at $844.99 at Newegg.
However, price per gigabyte isn't everything — consider factors like warranty, performance specs, brand reliability, and your specific capacity needs. Check each WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP 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 WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP 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 WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP at $0.0469//GB. That is approximately 35% better value per gigabyte.
What is the price per GB of WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP?
The WD Purple Pro 18TB 7200 RPM 512MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive - WD181PURP is currently priced at $0.0469/GB ($844.99 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 $487.28 at Amazon, which works out to $0.0305/GB.