Download Time Calculator
Download Time Calculator
Enter a file size and your connection speed to estimate how long the download will take — useful for planning large downloads or comparing internet plans.
A common source of confusion here is unit mismatch: file sizes are conventionally measured in bytes using the binary (1,024-based) convention for MB, GB, and TB, while internet connection speeds are advertised in bits using the decimal (1,000-based) convention — and since one byte equals eight bits, a "100 Mbps" connection downloads at roughly 12.5 megabytes per second, not 100. This calculator handles that conversion automatically, which is exactly the detail that trips people up when they try to do quick download-time math in their head and end up off by a factor of eight.
- Units matter: file size is measured in bytes (this tool uses binary/1,024-based MB, GB, TB), while connection speed is measured in bits per second (Mbps, using the decimal/1,000-based convention ISPs advertise) — 1 byte = 8 bits.
- Formula: time (seconds) = (file size in bytes × 8) ÷ (speed in bits per second).
- Real-world note: actual download speed is often lower than the advertised connection speed due to network overhead, so treat this as a best-case estimate.
How long does a 1 GB file take at 100 Mbps?
About 1 minute 26 seconds (1 GB = 8,589,934,592 bits ÷ 100,000,000 bps ≈ 85.9 seconds).
Why is my actual download slower than this estimate?
Advertised speeds are theoretical maximums — real-world factors like network congestion, Wi-Fi signal, and server limits usually reduce actual throughput.
Download Time Calculator
Enter a file size and your connection speed to estimate how long the download will take — useful for planning large downloads or comparing internet plans.
A common source of confusion here is unit mismatch: file sizes are conventionally measured in bytes using the binary (1,024-based) convention for MB, GB, and TB, while internet connection speeds are advertised in bits using the decimal (1,000-based) convention — and since one byte equals eight bits, a "100 Mbps" connection downloads at roughly 12.5 megabytes per second, not 100. This calculator handles that conversion automatically, which is exactly the detail that trips people up when they try to do quick download-time math in their head and end up off by a factor of eight.
- Units matter: file size is measured in bytes (this tool uses binary/1,024-based MB, GB, TB), while connection speed is measured in bits per second (Mbps, using the decimal/1,000-based convention ISPs advertise) — 1 byte = 8 bits.
- Formula: time (seconds) = (file size in bytes × 8) ÷ (speed in bits per second).
- Real-world note: actual download speed is often lower than the advertised connection speed due to network overhead, so treat this as a best-case estimate.
How long does a 1 GB file take at 100 Mbps?
About 1 minute 26 seconds (1 GB = 8,589,934,592 bits ÷ 100,000,000 bps ≈ 85.9 seconds).
Why is my actual download slower than this estimate?
Advertised speeds are theoretical maximums — real-world factors like network congestion, Wi-Fi signal, and server limits usually reduce actual throughput.