Website bandwidth calculator
Enter monthly visitors, pages per visit and average page size to estimate how much data your site serves each month, the average bandwidth that works out to, and a peak figure to size a hosting plan or port.
An assumption: traffic is never flat. 2–5 is common; use your own analytics if you have them.
Runs entirely in your browser. Nothing you type is sent anywhere.
How website bandwidth is calculated
The calculator multiplies traffic by page weight to get monthly transfer, then spreads it over an average month to get a rate:
monthly transfer = visitors × pages per visit × average page size average Mbps = monthly transfer in bits ÷ 2,629,746 s ÷ 1,000,000 peak Mbps = average Mbps × peak factor
2,629,746 seconds is an average month of 30.436875 days. The peak factor is an assumption you set, 3 by default: traffic is rarely spread evenly, and busy hours can run several times above the monthly average. Raise it for sites with sharp spikes such as launches, newsletters or live events.
Worked examples
- A mid-sized blog. 100,000 visitors × 3 pages × 2 MB = 600,000 MB, or 600 GB a month. Spread over an average month that is about 1.83 Mbps, and about 5.5 Mbps at a peak factor of 3.
- A busy content site. 1,000,000 visitors × 4 pages × 1.5 MB = 6 TB a month, about 18.25 Mbps on average and about 54.8 Mbps at a peak factor of 3.
Both figures are modest compared with a typical server port, which is why transfer allowances in GB or TB per month matter more than port speed for many hosting plans. To test a different monthly volume directly, TB to Mbps converts any amount per month into a sustained speed.
Assumptions and limits
- Page size. Use the transferred size of a typical page, including images, scripts and fonts. Your browser's developer tools show it in the network panel. Repeat visitors often load less because of caching, so a first-visit size overestimates slightly.
- What's not counted. File downloads, video, API calls, bots and crawlers all add transfer. Add them separately with the data transfer calculator if they are significant.
- CDNs. If a content delivery network serves most assets, your origin server moves much less than the total; the total is still what the CDN will bill.
- Peak factor. The default of 3 is a starting assumption, not a measurement. Server logs or analytics will show your real busiest hour.
Checking against real traffic
Once the site is live, compare the estimate with your host's traffic graph or access logs. If the real figure is much higher, the usual causes are larger images than expected, crawlers, or file downloads that were not in the page-size estimate. Trimming page weight cuts transfer in direct proportion: halving the average page from 2 MB to 1 MB halves the monthly total. Log totals in bytes can be turned into a rate with bytes to Mbps, and a measured transfer over a known time with the network throughput calculator.
Frequently asked questions
How much bandwidth does a website with 100,000 visitors a month need?
With 3 pages per visit at 2 MB each, about 600 GB of transfer a month. That averages about 1.83 Mbps, and about 5.5 Mbps at busy times if peaks run three times the average.
What is the difference between bandwidth and data transfer for hosting?
Data transfer is the total amount served in a period, usually GB or TB per month. Bandwidth is the rate, in Mbps or Gbps, at which it can be served at any moment. Hosting plans may limit either or both.
What peak factor should I use?
The default of 3 is a reasonable starting assumption for steady sites. Use a higher value if traffic arrives in bursts, and replace it with a figure from your own logs once you have them.