Work out file transfer times and a website's monthly data transfer and bandwidth needs.
Time = file size in bits ÷ speed in bits per second. A 1 GB file on a 100 Mbps connection takes 80 seconds at full speed, or about 89 seconds at 90% efficiency. Divide Mbps by 8 to get MB per second.
This page has two tools. The first calculates how long a file takes to download or upload given its size and your connection speed, with an efficiency setting for real-world overhead. The second estimates a website's monthly data transfer and the bandwidth it needs from visits, pages per visit and page size, including a peak-traffic multiplier.
Use it to check whether a connection is fast enough for backups or video, to size hosting plans and CDN budgets, or to understand why a plan's “unlimited” data may still be capped. Note that ISPs sell speed in megabits per second (Mbps), while file sizes are in megabytes (MB). For web addresses, see the URL Encode / Decode.
Everything is converted to bits and bits per second.
| File and speed | Time |
|---|---|
| 1 GB at 100 Mbps (no overhead) | 1 min 20 s |
| 1 GB at 100 Mbps (90% efficiency) | 1 min 29 s |
| 4 GB at 50 Mbps (90% efficiency) | 11 min 51 s |
| 1 TB at 1 Gbps (90% efficiency) | 2 h 28 min 9 s |
| Traffic | Monthly data | Average / peak |
|---|---|---|
| 10,000 visits a month, 3 pages, 2 MB each | 60 GB | 0.185 Mbps avg |
| 1,000 visits a day, 4 pages, 1.5 MB each | 180 GB | 0.556 Mbps avg |
Speeds are quoted in bits (Mbps) and file sizes in bytes (MB), so a 100 Mbps line moves at most 12.5 MB per second. Real throughput is lower because of protocol overhead, Wi-Fi quality, server limits and congestion — 85–95% of the line speed is typical on a good wired connection.
Convert the file size to bits, divide by your speed in bits per second, and allow for overhead. 1 GB at 100 Mbps is about 80–90 seconds.
Mbps is megabits per second; MB/s is megabytes per second. Divide Mbps by 8 to get MB/s.
Overhead, Wi-Fi, server speed, congestion and the other devices on your network all reduce the real speed.
Estimate monthly data (visits × pages × page size), find the average Mbps and multiply by a peak factor of 3× or more.
About 90% for a wired connection; lower for Wi-Fi or busy networks.
MB is 1,000,000 bytes (decimal); MiB is 1,048,576 bytes (binary).
1,000 GB in decimal units (1,024 GiB in binary).
Compress and resize images, enable caching and compression, minify code and use a CDN.
No. It is a planning estimate; caching, CDNs and traffic spikes change real usage.
No. Everything runs in your browser.
