Price per GB = drive price ÷ capacity in gigabytes. That is the entire formula. A 2TB SSD at $90 costs $90 ÷ 2000 GB = $0.045 per gigabyte. A 4TB hard drive at $80 costs $80 ÷ 4000 GB = $0.020 per gigabyte. Two numbers, calculated in seconds, that let you compare any two storage products instantly regardless of capacity, type, or brand.
The reason this metric matters: storage is sold in confusingly different sizes and price points specifically to make comparison difficult. A $129 drive is not obviously better or worse value than a $79 drive without knowing capacity. Price per GB cuts through that completely.
BuyPerUnit does this calculation automatically for every storage product it tracks, then ranks the results from cheapest to most expensive per gigabyte. If you'd rather skip the math, see the live price-per-GB rankings.
The Formula
Price Per GB = Total Price ÷ Capacity in Gigabytes
That is it. Three inputs: price, capacity, division. The result is a dollar amount — typically written as $/GB — that represents the cost of each gigabyte of storage on that specific drive.
The only potential confusion: manufacturers sometimes list capacity in terabytes (TB) rather than gigabytes. The conversion is straightforward:
- 1TB = 1,000 GB (for calculation purposes — technically 1TB = 1,024 GB, but retailers use 1,000)
- 2TB = 2,000 GB
- 4TB = 4,000 GB
- 500GB = 500 GB (no conversion needed)
Worked Examples
Here are five real calculations at different price and capacity points:
| Drive | Price | Capacity | Calculation | Price/GB |
|---|---|---|---|---|
| Kingston NV3 | $78 | 2TB (2,000 GB) | $78 ÷ 2,000 | $0.039/GB |
| Crucial P3 Plus | $84 | 2TB (2,000 GB) | $84 ÷ 2,000 | $0.042/GB |
| WD Blue SN5000 | $91 | 2TB (2,000 GB) | $91 ÷ 2,000 | $0.046/GB |
| Samsung 990 Pro | $149 | 2TB (2,000 GB) | $149 ÷ 2,000 | $0.075/GB |
| Sabrent Rocket 5 | $185 | 2TB (2,000 GB) | $185 ÷ 2,000 | $0.093/GB |
All five drives hold the same amount of data. The Samsung 990 Pro costs nearly twice as much per gigabyte as the Kingston NV3. The 990 Pro is a genuinely excellent drive — but that calculation makes it impossible to pretend the premium is small.
Now compare across different capacities:
| Drive | Price | Capacity | Price/GB |
|---|---|---|---|
| Crucial P3 Plus 1TB | $59 | 1,000 GB | $0.059/GB |
| Crucial P3 Plus 2TB | $84 | 2,000 GB | $0.042/GB |
| Crucial P3 Plus 4TB | $160 | 4,000 GB | $0.040/GB |
The 2TB and 4TB drives offer meaningfully better value per gigabyte than the 1TB. This is the capacity sweet spot effect — larger drives usually cost less per GB than smaller drives up to a point, after which the cost flattens or rises again.
Why Sticker Price Is Actively Misleading
Retailers know that most buyers anchor on total price rather than per-gigabyte cost. This is why you'll see:
Artificially small capacities at "low" prices. A $39 500GB SSD looks like a bargain next to an $84 2TB SSD — until you calculate that $39 ÷ 500 GB = $0.078/GB versus $84 ÷ 2,000 GB = $0.042/GB. The "cheap" drive costs nearly twice as much per gigabyte.
Premium drives marketed on spec, not value. A $185 Gen 5 NVMe drive might have the fastest sequential read speed in the category, but at $0.093/GB it costs more than twice the per-GB cost of a Gen 4 drive that is half as fast on benchmarks. The spec sheet makes the expensive drive look attractive; the per-GB calculation makes the premium look enormous.
Bundle deals that obscure individual pricing. When an SSD is bundled with a cable, heatsink, or USB enclosure, the accessory cost is baked into the price — making the drive look more expensive per GB than it actually is. Calculate based on the drive cost alone if you can determine it; otherwise treat the bundle price as the floor.
Sale prices against inflated "regular" prices. A drive marked "50% off" from $200 to $100 is not necessarily a deal if the regular market price for that drive is $89. Always calculate $/GB at the actual current price and compare against the market — not against an artificial "was" price.
"Was $149, now $99" is a retailer narrative. "This drive costs $0.050/GB and the market rate for this category is $0.042–$0.058/GB" is useful information. The per-GB calculation puts you in control of the comparison.
Applying Price Per GB Across Storage Types
The metric works across all storage categories, but the reference ranges differ significantly by type. You cannot compare an SSD's $/GB to a hard drive's $/GB and conclude anything about value — you need category-specific benchmarks:
| Storage Type | Good Price/GB (2026) | Notes |
|---|---|---|
| NVMe Gen 3/4 SSD | Under $0.08/GB | Under $0.06 is great |
| SATA SSD | Under $0.07/GB | Under $0.055 is great |
| 3.5" Desktop HDD | Under $0.022/GB | Under $0.018 is great |
| 2.5" Portable HDD | Under $0.04/GB | Portability premium is real |
| NAS HDD (IronWolf, Red) | Under $0.025/GB | NAS-tuned firmware commands premium |
| DDR4 RAM | Under $2.50/GB | RAM $/GB is much higher than storage |
| DDR5 RAM | Under $3.50/GB | Prices falling; check live |
RAM is listed here to illustrate why cross-category comparison fails: DDR4 at $2.50/GB looks astronomically expensive against an SSD at $0.05/GB. They serve completely different purposes, operate at different speeds, and exist at different price tiers for structural reasons. Price per GB is an intra-category tool, not a cross-category one.
The Practical Shopping Workflow
Here is how to use price per GB effectively on a real purchase:
- Identify your category. NVMe SSD? SATA SSD? External hard drive? RAM? Know the reference range for that category.
- Calculate $/GB for each option you're considering. Total price ÷ GB. Simple division.
- Compare against the reference range. Is this drive in "good," "great," or "overpaying" territory?
- Check across retailers. The same drive may be $10 to $20 cheaper at a different retailer on any given day.
- Act on genuinely great prices. If a drive from a reputable brand hits the "excellent" tier, that is the signal to buy — prices fluctuate, and the floor does not stay visible for long.
BuyPerUnit automates steps 2 through 4 for storage products: every drive is pre-calculated, pre-ranked, and shown with live prices from multiple retailers. The workflow collapses to "see which drive is cheapest per GB right now" rather than managing a spreadsheet.
Browse Storage Ranked by Price Per GB at BuyPerUnit →Frequently Asked Questions
How do you calculate price per GB?
Divide the total price of the drive by its capacity in gigabytes. Example: a $90 drive at 2TB = $90 ÷ 2,000 GB = $0.045 per GB. For drives listed in terabytes, multiply by 1,000 to convert to gigabytes first.
What is a good price per GB for storage?
It depends on the storage type. For NVMe SSDs: under $0.08/GB is good, under $0.06/GB is great. For desktop hard drives: under $0.022/GB is good, under $0.018/GB is excellent. For RAM: DDR4 under $2.50/GB is solid, DDR5 under $3.50/GB is fair. BuyPerUnit shows live rankings for all of these categories.
Why is price per GB better than just comparing prices?
Because drives come in different capacities, comparing raw prices tells you nothing about value. A $50 drive that holds 500GB costs more per gigabyte than a $90 drive that holds 2TB. Price per GB normalizes the comparison so every drive can be ranked on equal footing.
Does price per GB apply to RAM and SSDs equally?
The calculation applies to both, but the numbers are on completely different scales. RAM costs $2 to $5 per GB while SSDs cost $0.04 to $0.10 per GB. These are different products with different performance characteristics — use price per GB within a category to compare options, not across categories.