100 MBPS4 GB0.3 seconds12.5 MB/sAbout Bandwidth Calculator
How long will a big download take? How much time does a bandwidth upgrade save? How long to upload 50GB to cloud storage? These all reduce to knowing two of bandwidth, file size and time and solving for the third. This tool turns that triangle into an interactive calculator: edit any two values and the third recomputes instantly, with Mbps/Gbps and MB/GB/TB unit switching and a live MB/s download speed. Great for estimating transfers, sizing upgrades and planning uploads. All math runs locally. Tip: Bookmark this tool for quick access during network troubleshooting. All queries are made directly from your browser — no command-line tools required.
Use Cases
- Big-file download — Enter size and bandwidth to estimate download time and decide whether an upgrade is worth it.
- Cloud upload planning — Estimate how long a video backup takes and schedule uploads off-peak.
- Bandwidth upgrade ROI — Compare transfer time at 100 Mbps vs 1 Gbps to quantify the upgrade payoff.
- Streaming bitrate — Derive the video bitrate and file volume your upload bandwidth can sustain.
- Remote sync — Estimate branch-to-HQ data-sync time to plan backup windows.
- CDN cache sizing — Estimate how long it takes to warm a CDN cache with a given file set and available edge bandwidth.
- Live stream budget — Calculate the minimum upload bandwidth needed to stream a given bitrate to a single remote viewer.
FAQ
Are Mbps and MB/s the same?
No. 1 byte = 8 bits, so 100 Mbps equals about 12.5 MB/s real download speed; the tool shows both.
Why is real download slower than calculated?
The theoretical value ignores protocol overhead, TCP handshake, server throttling and jitter — real speed is usually ~80% of it.
Are upload/download separate?
It uses a single bandwidth; for asymmetric links (e.g. ADSL), estimate upload time with the upload bandwidth separately.
Is it real-time?
Yes. Editing any input instantly recomputes the other two — no submit needed.
Is data uploaded?
No. All calculation runs locally in your browser with no network requests.
Any browser compatibility requirements?
This tool works in all modern browsers (Chrome, Firefox, Edge, Safari). No plugins or extensions required.
Can I use it offline?
After initial load, most features work offline. The core logic runs entirely in your browser with no network dependency.