Dropbox needs no introduction. Amazon S3, if you've heard of it at all, probably sounds like something for developers — and it is, in the sense that it wasn't built with a "share this folder with mom" button. But under the hood, S3 is also just a place to put files, and for a personal backup, that's most of what you actually need. Here's what Amazon S3 vs Dropbox actually comes down to: what each one is, how the pricing really works, and whether S3 is genuinely cheaper.

What Amazon S3 actually is

Dropbox is a product: sign up, install the app, drag files into a folder, and everything syncs and shows up on your phone with sharing links and version history built in. Amazon S3 is a layer underneath products like that — object storage that Amazon rents out by the gigabyte, with no app, no gallery view, and no "share" button of its own. You create a bucket (a storage container) and an access key, and then it's up to whatever software you point at it — in this case, Sync — to decide how files actually get uploaded, browsed, and organized.

That difference isn't a knock on S3. It's the reason S3 can be cheaper: you're not paying for a polished consumer app layered on top, because there isn't one included. You're paying for storage, and only storage.

How S3 pricing actually works

Dropbox (like Google Drive and OneDrive) sells storage in flat tiers — pay one monthly or annual fee, get a set amount of space plus the app and its features. S3 works the opposite way: there's no flat fee for having a bucket at all. You pay per GB stored per month, plus smaller charges for requests (uploading, listing, downloading files) and for data you transfer out of AWS. Store nothing, pay nothing; store a little, pay a little.

This is why S3 can look almost free for a personal photo backup and only becomes a real line item once you're storing serious volume or downloading large amounts repeatedly. It's a usage-based model, not a subscription — closer to a utility bill than a Dropbox plan.

So is S3 actually cheaper than Dropbox?

For raw storage, usually — but "usually" is doing real work in that sentence. S3's per-GB rate tends to beat the effective cost of a Dropbox plan once you're paying for extra storage on Dropbox's side, especially if you're only backing up and not relying on Dropbox's sharing or collaboration features. But S3 also bills for requests and for downloading data back out, charges Dropbox's flat fee doesn't itemize separately. And AWS pricing varies by region and changes over time, so a specific number quoted today may not hold next year.

The honest framing: if your use case is "store a phone's worth of backups and rarely pull large amounts back down," S3's model tends to favor you. If you're comparing total cost for heavy day-to-day file access and sharing, the comparison gets murkier fast. Check AWS's current pricing for your region and expected usage rather than trusting a single "S3 is X% cheaper" claim — that includes ours.

You don't have to pick one

This isn't really an either-or decision. With Sync, Dropbox and Amazon S3 are both just drives in the same app — you can keep Dropbox around for what it's good at (quick sharing, browsing from anywhere) while routing your actual backup to S3 for the lower storage cost, or run both side by side for redundancy. If you want the step-by-step setup, our guide to backing up photos to Amazon S3 covers connecting S3 as a drive and creating your first Backup task.

What it costs (in Sync)

Connecting one drive — Dropbox, Amazon S3, or anything else Sync supports — is free, ad-supported. Connecting more than one at the same time, so you can actually compare or combine them, is part of Sync's paid upgrade: a subscription or a one-time lifetime purchase, either of which unlocks unlimited drives at once, along with USB/external drive support and the built-in Wi-Fi web server.

Get Sync

Sync connects to Amazon S3, Dropbox, Google Drive, OneDrive, Box, and local storage from one app on iPhone and iPad, Android, Mac, and Windows. For the hands-on setup, see our guide to backing up photos to Amazon S3; if you're weighing S3 against the rest of the field, our Google Drive vs Dropbox vs OneDrive comparison covers the other three.

Frequently asked questions

What is Amazon S3, exactly?

Amazon S3 is Amazon's object storage service — the raw infrastructure that a huge number of apps and websites use to store files behind the scenes. It has no consumer app, no built-in photo gallery, no share-a-link button; you get a bucket (a storage container) and an access key, and it's up to whatever app you connect to decide how files get in and out. Dropbox, by contrast, is a finished consumer product built on top of storage like this — sync clients, a mobile app, sharing links, and a web interface all included.

Is Amazon S3 actually cheaper than Dropbox?

Often, for raw storage — but it's not a clean apples-to-apples comparison. S3 charges per GB stored per month, plus separate charges for requests and data transfer out; Dropbox bundles storage into a flat subscription that also includes the app, sharing, and support. For a personal backup that mostly sits there and rarely gets downloaded in bulk, S3's metered pricing tends to undercut a comparable Dropbox plan once you're paying for extra storage. Check AWS's current pricing for your region and expected usage before assuming a specific number — it varies enough that "S3 is cheaper" isn't a guarantee for every case.

What does Amazon S3 cost, roughly?

S3's standard storage tier is priced per GB per month, with additional (usually small) charges for PUT/GET requests and for data you download out of AWS. There's no flat monthly fee just to have a bucket — you pay for what you actually store and move. That's the opposite model from Dropbox's tiered flat-rate plans, and it's why S3 can look nearly free for a modest personal backup and only starts to add up at real scale.

Do I have to choose between S3 and Dropbox?

No — with Sync, both are just drives in the same app. You can keep Dropbox for the things it's good at (sharing, browsing on the go) and add S3 as a second, cheaper backup destination, or move entirely to S3 if you don't need Dropbox's extras. Our guide to backing up photos to Amazon S3 walks through connecting S3 as a drive and setting up your first backup task.

Is S3 harder to use than Dropbox?

The initial setup is more involved — you create a bucket and an access key in the AWS console before you can use it, versus just signing in to Dropbox. After that one-time step, though, Sync treats S3 like any other drive: add it, create a Backup task, run it when you want. The ongoing experience isn't harder, just the on-ramp is longer.

Can I back up straight to S3 with Sync?

Yes. Add Amazon S3 as a drive using your AWS access key and bucket details, then create a Backup task with your phone's Camera Roll (or any folder) as the source and the bucket as the destination. Connecting one drive, S3 included, is free and ad-supported; connecting S3 alongside other drives at the same time is part of Sync's paid upgrade — a subscription or a one-time lifetime purchase.