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About This Calculator
Bandwidth determines how much data can be transmitted over a network connection in a given amount of time. This calculator converts between bits, bytes, kilobits, megabits, and gigabits per second while estimating file transfer durations at your connection speed. It's invaluable for network planning, streaming quality decisions, and diagnosing bottlenecks.
Quick Tips
- 1 Divide file size in megabytes by 8 to convert to megabits for speed comparison.
- 2 Real throughput is typically 60-80% of your advertised bandwidth speed.
- 3 Streaming 4K video requires a sustained 25 Mbps minimum per device.
Example Calculation
Download a 4.7 GB movie on 100 Mbps internet.
File: 37,600 Mb | Download time: 6 min 16 sec | Actual (~80%): 7 min 50 sec
How Download Time Is Calculated
Download time equals file size divided by connection speed. Since file size is in megabytes (MB) and speed is in megabits per second (Mbps), you must multiply the file size by 8 to convert to megabits first (1 byte = 8 bits).
Megabits vs Megabytes
Internet speeds are measured in megabits per second (Mbps), while file sizes are in megabytes (MB). There are 8 bits in a byte, so a 100 Mbps connection downloads about 12.5 megabytes per second. This distinction is critical for accurate calculations.
Real-World Speed Factors
Actual download speeds are typically 60% to 80% of your advertised connection speed due to network overhead, congestion, server limitations, and protocol overhead. Wi-Fi is generally slower than a wired Ethernet connection.
Common Internet Speeds
Basic broadband: 25 Mbps. Standard plans: 100-200 Mbps. Fast plans: 300-500 Mbps. Gigabit: 1,000 Mbps. Fiber: up to 2,000+ Mbps. 5G wireless: 100-1,000 Mbps. 4G LTE: 10-50 Mbps.
Frequently Asked Questions
Your ISP speed is in megabits, not megabytes. Divide by 8 to get megabytes per second. Additionally, network overhead, server limits, Wi-Fi interference, and other devices sharing your connection reduce actual throughput.
At 100 Mbps, 1 GB (1,000 MB) takes about 80 seconds or 1 minute and 20 seconds. This is the theoretical maximum; real-world time is typically 20-40% longer due to overhead.
SD streaming needs 3-5 Mbps, HD needs 5-10 Mbps, 4K needs 25-35 Mbps, and 8K needs 50-100 Mbps per stream. For multiple simultaneous streams, add the requirements together.
Upload speed matters for video calls (2-5 Mbps), live streaming (5-10+ Mbps), cloud backups, and sending large files. Most ISP plans have much slower upload than download speeds, except for fiber connections.