Bandwidth Calculator

Q: How do I calculate download time?

Convert file size to bits (1 byte = 8 bits, 1 MB = 8 Mbits). Divide by speed in bits per second. Example: a 1 GB file (8 Gbits) at 100 Mbps = 8,000 Mbits ÷ 100 Mbps = 80 seconds.

Q: What is the difference between Mbps and MB/s?

Mbps (megabits per second) is how internet speeds and network links are measured. MB/s (megabytes per second) is how file sizes and transfer speeds are typically shown in operating systems. 1 MB/s = 8 Mbps. A 100 Mbps connection downloads at approximately 12.5 MB/s.

Q: How much data can I transfer in a month on a 100 Mbps line?

At 100 Mbps continuously: 100 Mbps × 3600 s/hr × 24 hr/day × 30 days = 25,920 GB per month (about 25 TB). In practice, links are never fully utilized 24/7. A 100 Mbps line at 20% average utilisation transfers about 5 TB per month.

Calculate download/transfer time, convert between Mbps and MB/s, estimate data throughput per hour, and see per-user bandwidth when sharing a connection.

Bandwidth & Transfer Time Calculator

Data Size

Size Unit

Connection Speed

Speed Unit

Number of Users Sharing (optional)

Bandwidth Results

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Transfer Time

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Speed (Mbps)

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Speed (MB/s)

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Data per Hour

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Per User Bandwidth

Formulas

Transfer Time (s) = File Size (bits) ÷ Speed (bits/sec) File Size in bits = File Size (bytes) × 8 1 MB = 1,000,000 bytes · 1 GB = 1,000,000,000 bytes · 1 TB = 1,000,000,000,000 bytes Speed conversion: 1 Mbps = 1,000,000 bits/sec = 125,000 bytes/sec = 0.125 MB/s 1 MB/s = 8 Mbps 1 Gbps = 1,000 Mbps

Practical Examples

Example 1: How long to download a 4 GB game on a 100 Mbps connection?

4 GB = 4,000 MB = 32,000 Mbits 32,000 Mbits ÷ 100 Mbps = 320 seconds = 5 minutes 20 seconds

Example 2: How much data can a 1 Gbps link transfer in an hour?

1 Gbps × 3600 s = 3,600 Gbits = 450 GB per hour

Example 3: 50 users sharing a 200 Mbps link — bandwidth per user?

200 Mbps ÷ 50 users = 4 Mbps per user (Assuming equal distribution and all users active simultaneously)

Understanding Bandwidth vs. Throughput

Bandwidth is the maximum theoretical capacity of a link. Actual throughput is always lower due to:

Protocol overhead — TCP/IP headers, retransmissions, and ACKs reduce effective throughput by 5–10%.
Network congestion — shared links slow down when multiple users are active.
Storage speed — a 10 Gbps link can't transfer faster than your drive reads at ~500 MB/s (SSD).
WiFi overhead — wireless throughput is typically 50–70% of the link's rated speed.
Distance and latency — high-latency links (satellite) reduce TCP throughput regardless of bandwidth.

Frequently Asked Questions

How do I calculate download time?

Convert file size to bits (multiply by 8), then divide by your speed in bits per second. Example: 10 GB file = 80 Gbits = 80,000 Mbits. At 100 Mbps: 80,000 ÷ 100 = 800 seconds = 13 minutes 20 seconds.

What is the difference between Mbps and MB/s?

Network speeds are in megabits per second (Mbps). File transfer speeds shown by your OS are in megabytes per second (MB/s). 1 MB = 8 Mb, so 1 MB/s = 8 Mbps. A 100 Mbps internet connection downloads files at about 12.5 MB/s.

How much data can I transfer in a month on a 100 Mbps line?

If used at 100% utilisation 24/7: 100 Mbps × 2,592,000 seconds/month = 259,200 Gbits = ~32,400 GB (32 TB). At a more realistic 20% average utilisation: ~6.5 TB per month. For internet connections, most ISPs don't throttle until 1–10 TB/month depending on plan.