Bandwidth Calculator
Calculate download / upload time from file size and internet speed
File Size
Internet Speed
Common Speeds
4G LTE: ~20–50 Mbps
5G: ~100–1,000 Mbps
Broadband (India): 25–200 Mbps
Fiber: 100–1,000 Mbps
Transfer Time
Seconds
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Minutes
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Hours
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With overhead (~10%)
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File in bits
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File in bytes
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Bits vs Bytes
Internet speeds are measured in bits per second (bps), while file sizes are in bytes. There are 8 bits in a byte. A 100 Mbps connection transfers 100 million bits — or 12.5 megabytes — per second. So a 1 GB file (= 8 Gb = 8,000 Mb) takes 80 seconds at 100 Mbps (8,000 Mb ÷ 100 Mbps).
Actual speeds are usually lower than advertised due to network overhead (TCP/IP headers, protocol overhead, congestion, latency). A 10% overhead estimate is used here for the "real-world" figure.
lightbulb Example
Download 4 GB movie at 50 Mbps:
14 GB = 32,000 Mb
2Time = 32,000 / 50 = 640 s
✓ ~10.7 minutes (11.8 min with overhead)
quizFrequently Asked Questions
What is the difference between bandwidth and throughput?
Bandwidth is the maximum theoretical data rate a network can carry (e.g., 100 Mbps on your plan). Throughput is the actual data rate achieved in practice — always lower due to network overhead, congestion, latency, and protocol inefficiency. A 100 Mbps connection typically achieves 70–90 Mbps real throughput.
How long does it take to transfer 1 GB at various speeds?
At 10 Mbps: ~14 minutes. At 100 Mbps: ~1.4 minutes. At 1 Gbps: ~8 seconds. Remember: file size in gigabytes must be converted to gigabits — 1 GB = 8 Gb. A 1 GB file at 100 Mbps takes 8 Gb ÷ 0.1 Gbps = 80 seconds theoretically, more in practice due to overhead.
Why does my internet speed test show less than my plan speed?
Your ISP plan speed is "up to" — a ceiling, not a guarantee. Real-world factors: server location (distant servers = higher latency), Wi-Fi interference (use a wired connection for accurate tests), network congestion during peak hours, and VPN overhead. Run speed tests at different times on a wired connection for the most accurate measure.