Bandwidth is the amount of data your website sends to visitors over a given period.
In web hosting, bandwidth usually means data transfer: the total amount of data your site sends out to visitors each month. Every time someone loads a page, their browser downloads the HTML, images, scripts and fonts. All of that counts towards your bandwidth.
For example, if your average page is 2 MB and you get 10,000 page views a month, your site uses about 20 GB of bandwidth. A gallery site with large photos or downloadable videos will use far more than a text-heavy blog.
Bandwidth vs data transfer
Strictly speaking, bandwidth is the maximum speed of a connection, like the width of a pipe, measured in megabits or gigabits per second. Data transfer is how much actually flows through the pipe over time, measured in gigabytes. Hosts often use "bandwidth" for both, so check which one a plan means when it shows a number.
How to calculate how much bandwidth you need
A quick estimate:
- Find your average page size, using a speed test tool or your browser's developer tools.
- Multiply by your monthly page views from your analytics.
- Add a margin of 50% or so for traffic spikes, bots and file downloads.
So 1.5 MB pages × 30,000 views = 45 GB, and with a margin you'd plan for about 70 GB a month. Most small business sites use well under 100 GB.
What happens if you run out of bandwidth
On plans with a hard cap, going over the limit can mean your site is suspended until the next month, slowed down, or billed for extra usage. Plans marketed as unmetered don't charge for transfer, but they still have fair use rules around server resources like CPU and memory, which are usually the real limit for busy sites.
How to reduce your bandwidth usage
- Compress images and serve them in modern formats like WebP.
- Turn on compression such as gzip or Brotli for text files.
- Use a CDN so cached copies of your files are served from the CDN's network instead of your server.
- Set browser caching headers so returning visitors don't download the same files again.
- Use hotlink protection to stop other sites embedding your images and using your bandwidth.
- Block bad bots that crawl thousands of pages for no benefit.
Common bandwidth myths
"Unlimited bandwidth" doesn't mean your site can handle unlimited visitors. Speed under load depends on CPU cores, memory and caching, not just transfer allowance. On AblePage, plans don't meter bandwidth, and every plan works with Cloudflare and other CDNs.