The fixed price of a Lightsail machine includes three things: the machine, its disk and a transfer allowance, that is, an amount of data it can send each month at no extra cost. Every time someone opens your website, downloads a file or you download a backup, allowance gets used. Most websites don't even reach a tenth of it; but a site with lots of images, videos or downloads, or a backup that is pulled down to the office every night, can go over. And then Lightsail charges for the excess, per GB, at a rate that depends on the region.
This guide explains what counts, where to check it and what to do if you are getting close to the limit.
Before you start: what each thing means
- Data transfer
- The amount of information going in and out of your machine over the internet, measured in GB per month.
- Included allowance
- The GB per month your plan allows at no extra cost. The bigger the plan, the bigger the allowance.
- Outbound
- What your machine sends: pages, images, downloads. This is what uses up the allowance and what gets charged when you go over.
- Inbound
- What your machine receives: file uploads, visitors requesting pages. Lightsail does not charge for inbound traffic.
- Overage
- The GB that exceed the allowance. They are charged per GB at your region's rate, on the end-of-month bill.
- CDN (content delivery network)
- A service that keeps copies of your images and files in many places around the world and serves them itself, so your machine doesn't spend transfer on them. Lightsail has one of its own.
What uses allowance and what doesn't
Everything that leaves the machine towards the internet uses allowance: every page served, every image, every download, every email with attachments, and also whatever you download from it (a backup, a database dump). Inbound traffic does not count (visitors requesting, uploads) nor, in general, does traffic between your machine and other AWS services in the same region, such as a managed database or an S3 bucket in the same region. Watch out for what goes to another region or to the internet: that does count.
The allowance is per machine and is not shared: two small machines have two allowances. If a machine is stopped it doesn't use any, but it doesn't accumulate either.
Where to see how much you have used
In the Lightsail console, open the machine, Metrics tab, and choose the Outgoing data transfer metric with the month as the period. The graph shows GB per day; add them up roughly or look at the trend. In the account's Billing tab (top menu), the Lightsail section breaks down the month's overage, if there is any. There is no real-time counter saying "you have X GB left", so it is worth checking the graph mid-month if your site moves a lot of data.
What happens when you go over
Nothing gets cut off: the website keeps working. The GB that exceed the allowance are simply charged at your region's rate and appear on the bill as Lightsail data transfer. For a normal site that goes slightly over, it is cents or a few euros. For a site serving videos or large files, it can be more than the machine itself. That is why it pays to know in advance.
How to cut consumption
- Lighter images. This is the number one cause. Compressing images and serving them in modern formats (WebP) cuts transfer by half or more without anyone noticing. In WordPress there are plugins that do it on their own.
- Browser caching. Have the server tell the browser to keep images and stylesheets for a few days: repeat visits don't download them again. It is a web server setting or a plugin.
- A CDN in front. Lightsail has its own distribution (Networking tab, "Create distribution") that serves your static content from its network and has its own separate allowance. For sites with lots of images it is the definitive solution.
- Backups, inside AWS. If you download a backup to the office every night, that is outbound transfer. Store it in an S3 bucket in the same region, which doesn't use allowance, and download only what you need.
- Videos elsewhere. A video hosted on the machine eats up the allowance in a few visits. Upload it to a video platform and embed it.
When upgrading the plan pays off
If you go over every month and have already done the above, compare: the overage you pay against the price difference with the next plan, which brings more allowance (and more machine). Sometimes the bigger plan works out cheaper than the overage. The change is done with a snapshot, as explained in the guide on changing plan.
What can go wrong
The graph shows huge spikes on some days
It is usually an aggressive crawler, a flood of requests or someone downloading your whole site. Check the web server logs for those hours; an application firewall or blocking the IP doing it is usually enough.
I am being charged for transfer and the site hardly gets any visits
Check whether something is leaving the machine without you seeing it: backups being sent elsewhere, a monitoring service downloading, or the machine itself sending email with attachments. The hourly outgoing transfer graph tells you when it happens.
I don't know what my plan's allowance is
It appears on the machine's card in the Lightsail console, next to the price. Every plan states it in GB per month.
In Simplio
In Simplio every Lightsail machine shows a bar with the transfer used against what its plan includes, for all your accounts in the same list, and it emails you when a machine goes past 80 % of its allowance, with time to react. On the Costs screen you can see how much the overage is costing you before the bill arrives.
The same task, in AWS and in Simplio
| In the AWS console | In Simplio | |
|---|---|---|
| Knowing how much you have used | Metrics tab of each machine, adding up GB by eye, no warning | Allowance bar per machine (used / included) and a warning at 80 % |
| Several machines and accounts | One by one | All in the same list, sorted by consumption |
| Seeing what the overage cost you | End-of-month bill | Estimated overage cost on the Costs screen before the month ends |