Bandwidth and download time
Download time from Mbps ÷ 8 = MB/s in decimal units: 1 GB over 100 Mbps takes 80 seconds. File sizes in MB/GB/TB, an 85%–95% real-world efficiency factor, and a 20M–1000M tier table with speeds and per-GB times.
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Download time
Decimal units: 1 MB = 1e6 bytes, 1 GB = 1000 MB.
Enter a file size to calculate the download time
Theoretical speed: 0 · Theoretical time: 0 · File size: 0
What this tool does
- Size a plan before buying: see what Mbps is needed to pull 50 GB in ten minutes.
- Check an ISP claim: a 100M line should reach 12.5 MB/s; compare with a speed test.
- Plan streaming or backups from your upload bandwidth.
Example
Input
5
Output
200 Mbps 下载 5 GB：理论 200 秒（3 分 20 秒） 带宽换算：200 Mbps ÷ 8 = 25 MB/s 文件大小（十进制）：5 GB = 5000 MB 按 100% 实际效率：25 MB/s，耗时 200 秒（3 分 20 秒） 常见带宽档位（理论 MB/s，下载 1 GB 的秒数）：20M = 2.5 MB/s / 400 s、50M = 6.25 MB/s / 160 s、100M = 12.5 MB/s / 80 s、200M = 25 MB/s / 40 s、300M = 37.5 MB/s / 26.666667 s、500M = 62.5 MB/s / 16 s、1000M = 125 MB/s / 8 s 提示：运营商带宽是十进制比特口径，Windows 显示的 MB/s 若按二进制换算会小约 4.9%。
100 Mbps ÷ 8 = 12.5 MB/s, so 1 GB (1000 MB decimal) takes 80 seconds.
Frequently asked questions
Why is a 100M line only 12.5 MB/s?
Bandwidth is quoted in megabits per second while download tools show megabytes per second. One byte is eight bits, so divide by 8: 100 ÷ 8 = 12.5. Nothing is missing — the units differ.
Why 1000 MB per GB instead of 1024?
Drive makers and network engineers use decimal units (1 GB = 1000 MB = 1e9 bytes) while Windows shows binary units (1 GiB = 1024 MiB), which makes the same disk look about 7% smaller. This tool uses decimal, matching ISP practice.
Can real speeds hit the theoretical value?
Usually 85%–95%. TCP/IP and PPPoE overhead, server throttling, Wi-Fi interference and old routers all take a cut. Set efficiency to 90% for a realistic estimate.
Are upload and download the same?
Most home connections are asymmetric: 1000M/50M means 1000 Mbps down and 50 Mbps up, only 5%. Backups, streaming and file sharing depend on the upload figure.
Does 1000M really download 1 GB in 8 seconds?
In theory yes (1000 Mbps ÷ 8 = 125 MB/s, 1000 MB ÷ 125 = 8 s). In practice the server's uplink, disk write speed and NIC or router become the bottleneck, so 20–40 seconds is common.
Does it cover bitrate requirements?
Indirectly: a platform asking for 6000 kbps means 6000 ÷ 8 = 750 KB/s, about 6 Mbps of upstream. Add 30% headroom and keep upload above 8 Mbps.
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