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Comparisons of free cloud storage almost always come down to a single column of numbers. Google gives you 15 GB, Dropbox gives you 2 GB, and the conclusion writes itself.
That column is misleading, because the largest free allowance on the list is not storage for your files. It is storage for your files and your entire email history and every photo you have ever backed up, drawn from one shared pool. Run the arithmetic and the ranking looks different.
The Number Is Shared, Not Dedicated
Google’s own documentation is explicit about this. Every free account gets 15 GB shared across Gmail, Google Drive and Google Photos. There is no separate Drive allowance underneath it.
So the honest version of the table has a column that most roundups leave out.
| Free plan | Advertised | Shared with | Realistically left for files |
|---|---|---|---|
| Google Drive | 15 GB | Gmail and Google Photos | Whatever your mail and photos have not already taken |
| Dropbox Basic | 2 GB | Nothing, it is files only | 2 GB |
| OneDrive | 5 GB | Outlook.com attachments | Close to 5 GB for most people |
Working the Arithmetic on a Normal Account
Consider an account that has existed for a decade. Ten years of email with attachments is commonly several gigabytes on its own. Turn on original-quality photo backup from a phone and the remainder disappears inside a year or two of holidays.
The result is an account showing 15 GB of storage where the practical room for a new project folder is a rounding error. Nothing is broken. The quota is simply doing what it always said it would.
Photo by Zan Lazarevic on Unsplash
Nothing is broken. The quota is simply doing what it always said it would.
What Happens When It Fills Up
This is the part worth knowing before it happens, because the consequence lands somewhere you would not expect.
Once you are over quota, Gmail stops accepting incoming mail. Messages sent to you bounce back to the sender, and you cannot send either, until you free space or upgrade. Your inbox does not quietly fill up in the background; correspondence is refused at the door.
The reason this catches people is that the failure surfaces in the wrong place. Photo backup fills the quota, and the symptom is a client saying their email to you bounced. Nobody connects those two events on the first attempt.
Dropbox Has a Different Catch
Dropbox does not share its quota, but its free tier restricts something else. Its paid Plus plan lists the ability to connect unlimited devices as a selling point, which tells you the free plan does not have that. If you use a laptop, a desktop and a phone, check the current device allowance before you build a workflow that assumes all three stay in sync.
It is a smaller trap than Google’s, and a more visible one. You find out at setup rather than eighteen months later.
Photo by Firmbee.com on Unsplash
Photo by Krzysztof Kowalik on Unsplash
Choosing on Something Other Than the Headline Number
Pick based on what your quota is competing with, not on which figure is largest.
| Your situation | Reasonable choice | Why |
|---|---|---|
| Heavy Gmail user, years of archive | Keep Drive for documents only | Your mail already owns most of the 15 GB |
| Phone photo backup is the priority | Budget for paid storage now | Photos outgrow every free tier, and quickly |
| A handful of working documents | Dropbox Basic is enough | 2 GB of real file space beats a contested 15 |
| Already on Microsoft 365 | OneDrive | The allowance is already paid for |
Two Things Worth Doing Today
Neither costs anything and both take a few minutes.
Check what is actually consuming the quota. Google publishes a storage management view that breaks the total down by service. Most people find one category they had no idea was that large, and it is rarely documents.
Turn off original-quality photo backup unless you want it. It is the single fastest way an account fills, and for phone snapshots the compressed setting is usually indistinguishable at viewing size.
Free-tier terms elsewhere tend to be misquoted in the same way, which is what I found when checking the password manager plans in Best Free Password Managers.
FAQ: Frequently Asked Questions
Is Google Drive really 15 GB free?
Fifteen gigabytes is the account total, shared with Gmail and Google Photos rather than reserved for Drive. The amount available for files is whatever those two have not already used.
What happens if my Google storage is full?
You cannot send or receive Gmail messages, and mail sent to you bounces back to the sender. Google also states that content may be deleted after two years over quota.
Which free cloud storage is biggest?
Google by the advertised figure. Dropbox by the amount that is exclusively yours for files. Which one is “biggest” depends on whether your email and photos are competing for the same pool.
Can I use several free accounts together?
You can, and people do, but splitting work across services means nothing is searchable in one place and restoring after a lost laptop becomes a scavenger hunt. Past a certain point, paying for one tier costs less than the time spent maintaining three free ones.
Storage figures and policies above reflect Google and Dropbox documentation as of 19 August 2026. Plans and prices vary by region and change without notice; check the provider’s own pages before deciding.