Storage Requirement Calculator
Work out how much storage you need from your OS, games and apps, with a recommended SSD size that leaves room for future installs.
How much storage do you actually need?
Game installs have grown faster than almost anything else in PC building. Titles that once fitted in 20 GB now routinely exceed 100, and a few pass 200. A 500 GB drive that felt generous a few years ago now holds Windows and three modern games.
Never fill an SSD completely
Solid-state drives need free space to manage wear levelling and garbage collection. Above roughly 80% full, write performance falls off noticeably, and a nearly full drive can slow to a crawl. Plan for 20% headroom on top of whatever you calculate, which is why the recommendation above is larger than the raw total.
Advertised capacity is not what you get
Manufacturers count a gigabyte as 1,000,000,000 bytes; Windows counts it as 1,073,741,824. A "1 TB" drive therefore shows as about 931 GB, before Windows and the recovery partition take their share. It is not false advertising, but it does mean planning with a little margin.
Tiering saves money
You do not need everything on your fastest drive. Windows and the games you play regularly belong on NVMe; a large SATA SSD or hard drive handles archives, media and the games you return to occasionally. Compare the cost of each tier with the SSD Speed Comparison.
Plan for growth
Whatever you calculate today, you will install more. Buying one 2 TB drive is usually better value than two 1 TB drives, and it leaves M.2 slots free for later — which matters, since filling those slots can cost you PCIe lanes elsewhere.
Frequently asked questions
Is 1TB enough for gaming?
It holds Windows and roughly six to eight modern AAA titles. If you keep several large games installed at once, 2 TB is the more comfortable choice and costs far less than twice as much.
Why does my 1TB drive show as 931GB?
Manufacturers count a gigabyte as a billion bytes; Windows uses 1,073,741,824. The difference is about 7%, and the recovery partition takes a little more.
Should I get one large drive or two smaller ones?
Usually one larger drive - better value per gigabyte, more flexible, and it leaves M.2 slots free. Two drives make sense when you want a fast system drive and cheap bulk storage.
How full can I let an SSD get?
Keep at least 15-20% free. Beyond about 80% full, write performance degrades noticeably as the drive struggles to find free blocks.