What is the Cost Per GB for Cloudflare CDN?

For Cloudflare’s standard Free, Pro ($20 / mo), and Business ($200 / mo) plans the cost-per-GB is effectively $0. I can (and routinely do) push 2-5 TB a month through those tiers without a penny of bandwidth overage. 

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Cloudflare only meters traffic when you move to a custom Enterprise contract, or when you bolt on specialised features such as Argo Smart-Routing ($5 + $0.10 / GB), Spectrum for raw-socket apps (custom), or R2 object storage (still $0 egress). 

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In a self-serve context, “unmetered” really does translate to no published per-GB fee as long as you stay within Cloudflare’s acceptable-use rules. 

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But, to really get into it, I’d break it into three main angles:

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1 ⟩ What I Actually Pay on Free, Pro, and Business

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On the public plans page Cloudflare tells me the monthly fee, gives me the WAF level, and calls the bandwidth “unmetered.” No footnotes mention a cap or $/GB surcharge. 

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In real life: one static-site owner bragged on Reddit that they clear 8 TB every month on the free tier; another free-plan user happily sits at 5-9 TB with zero push-back. 

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I’ve done the same on Pro, roughly 6 TB for $20, which works out to $0.003 / GB on my side of the ledger. That’s cheaper than Bunny’s volume tier and roughly two orders of magnitude less than AWS CloudFront list pricing.

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Section 2.8 Clause

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But there is a strings-attached clause. Cloudflare’s service-specific terms (formerly the famous “Section 2.8”) forbid using the vanilla CDN as a wholesale video or large-file delivery network. They explicitly say “video and large files hosted outside Cloudflare will still be restricted on our CDN.” 

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In other words, if I try to push multi-gig game installers or 4K livestreams 24/7, I’m going to get a polite e-mail from sales suggesting Cloudflare Stream, R2, or an Enterprise deal.

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2 ⟩ How Far Can I Stretch “Unmetered” Before Cloudflare Taps Me on the Shoulder?

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Because the limits are qualitative, I rely on community war stories:

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• Spamhaus DDoS (2013): a free-tier customer soaked up a ~300 Gbps attack. Cloudflare mitigated it and only asked them to upgrade to the $20 Pro plan afterwards. (Source)
• Enterprise anecdote: one throw-away account on Hacker News said they pay $5-10 k per month for roughly 70 TB plus 100 M requests, implying Cloudflare’s internal billback for high-volume enterprise traffic is somewhere in the $0.07 – $0.14 range including 24/7 support. (Source)
• Day-to-day free usage: Cloudflare staffers in the community forums routinely confirm that “we do not impose any bandwidth limitations, but we reserve the right to act on disproportionate load.” Translation: you can probably swing double-digit terabytes; once you look like Netflix they’ll nudge you upward. (Source)

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These stories line up with my own experience: normal web traffic is fine at almost any scale, but the minute my byte mix skews toward video or large binary blobs I know I’m on thin ice.

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3 ⟩ Why Cloudflare Can Afford to Price Bandwidth at $0 / GB

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You’re probably thinking “wait, this doesn’t make any sense”, and you’d be thinking logically. But, Cloudflare isn’t some oblivious money-leaking ship either. 

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Most of the magic comes from how Cloudflare buys and moves bits:

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• Settlement-free peering: Almost half the traffic that leaves Cloudflare’s edge rides free peering links rather than paid transit. In a decade-old but still illustrative blog post they pegged North American transit at $10 / Mbps-month un-peered and $8 peered. That’s ≈$0.03 / GB before discounts, and prices have only fallen since then.
• Bulk transit buys: Even their paid routes are bought in 100-plus Gbps commits, pushing unit cost down to fractions of a cent per gig. At $5 / Mbps-month (a realistic Europe figure) the raw math is $0.015 / GB. If peering eats half the traffic, the blended cost is closer to $0.007 / GB, pennies on the dollar compared with hyperscale clouds.
• Bandwidth Alliance: By convincing storage clouds like Azure, Backblaze, and Google to waive egress toward Cloudflare, they take upstream bandwidth off their books entirely. Free ingress plus cheap egress means Cloudflare’s marginal delivery cost often rounds down to zero. 

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All of this lets Cloudflare treat bandwidth the way mobile networks treat unlimited SMS: the incremental cost is so low it isn’t worth metering for 99 % of users.

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Putting a Number on the “Hidden” Cost Per Gig

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No cost is no fun, there needs to be a number to it. No worries, let’s dig one.

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Because the headline figure is $0, I reverse-engineer:

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1. Pro plan math – $20 / 6 TB = $0.003 / GB effective retail.
2. Enterprise anecdote – $7 500 (mid-point) / 70 TB = $0.10 / GB all-in for big-ticket support and SLAs. Still cheaper than AWS CloudFront’s $0.085 / GB for North America data.
3. Transit math – $5 / Mbps-month = $0.015 / GB raw. With 50 % free peering it’s firmly sub-penny.
4. R2 zero egress – Cloudflare literally sells storage with $0 bandwidth. They wouldn’t do that if their out-of-pocket were more than fractions of a cent.

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From those angles I’m comfortable pegging Cloudflare’s internal cost at $0.001–$0.005 / GB in cheap regions and maybe $0.02 / GB at the expensive edges. 

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So giving me 10 TB of unmetered transfer for $20 a month is still profitable as long as my traffic isn’t entirely in Sydney or São Paulo.

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When You Actually Pay by the Gig

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Cloudflare hides almost every per-GB fee behind optional add-ons:

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• Argo Smart-Routing – $5 base + $0.10 / GB over Argo traffic; great when you need lower tail latency, but otherwise I leave it off.
• Spectrum – TCP/UDP proxying for game servers, VoIP, SMTP, etc. Pricing is custom but still flat-rate for up to a bandwidth ceiling, then negotiated. You’ll see the keyword “cloudflare spectrum pricing” on their product page, not a $/GB table.
• Zero-Trust Tunnel seats – Cloudflare Tunnel itself is free for up to 50 users, then $7 per user per month. That’s per-seat, not per-GB, but I still see folks confuse it with bandwidth billing; hence the obligatory “cloudflare tunnels pricing” mention. 

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In each case the data transfer is again “unmetered” within the service’s own envelope; the meter kicks in only once you exceed that envelope.

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Cost Checklist for Cloudflare CDN Billing

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1. Is the bulk of my payload HTML + CSS + JS + images? If yes, Free/Pro/Business is perfect.
2. Do I serve a ton of video or multi-gig files? Route that through Cloudflare Stream or R2 to stay compliant.
3. Will a global low-latency edge make me real money? If so, I budget $5 for Argo and call it a day, even 20 GB routed through Argo still costs less than a latte.
4. Am I running bespoke TCP or UDP services? That’s Spectrum land; I treat it like a mini-Enterprise plan.
5. Am I crossing into 40 TB-plus monthly? Time to negotiate Enterprise. The price-per-gig rises into the five-to-ten-cent zone, but I also get phone-level support, dedicated account staff, and contract-level SLAs.

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What Happens If I Serve Copious Amounts of Data Through Cloudflare?

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Honestly? Probably nothing; at least not right away.

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If you’re like most of us; serving HTML, CSS, JS, maybe a bunch of images, you can get away with terabytes of monthly traffic on Free, Pro, or Business without so much as a raised eyebrow from Cloudflare. 

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I’ve done 6–8 TB on Pro, heard of others doing 10+ on Free, and Cloudflare staff in the forums routinely confirm they don’t hard-cap bandwidth on these plans. The system is built to let you run fast and cheap, as long as your use case stays inside the “normal web traffic” lane.

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But.

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If your traffic patterns start to drift; say, you’re pushing multi-gig video files, serving large downloadable binaries, or your site suddenly turns into a game launcher CDN clone, Cloudflare notices. And not in a dramatic, scary way either. They usually send you a kind, human e-mail. Something like:

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“Hey, we noticed this issue with our compliance. Want to chat about better-suited options?”

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Now, you’re in direct talks with their sales team, who will constantly nudge you. Now, if you ghost them and keep slamming their edge, especially non-cached stuff or high-cost regions; they can start throttling or de-prioritizing your traffic. 

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Let me be clear: this is not common. Most users won’t hit these issues. 

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But I always tell folks, if your app starts looking like a CDN, Cloudflare will treat it like one. They’re not here to subsidize your video startup with free egress. 

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So What Happens if You Don’t Buy Enterprise? 

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You keep running, probably forever, if your traffic looks like a website.

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However, if you have, even the most subtle compliance issues. Have a backup of your CDN operations ready. They will enforce terms when needed.

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And if they do? Fair enough. You’re not getting scammed. You just outgrew the free ride.

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