Networking · Data · Speed
Bandwidth
Calculator
Calculate download and upload times, convert between data units, estimate monthly website bandwidth, and find what internet speed you need for any activity.
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Result
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Unit
DL Time
Mode
Download / Upload Time
How long will it take to transfer a file at a given speed?
Common speeds
Common file sizes
Data Unit Converter
Convert any data size to all other units instantly.
Website Bandwidth Estimator
Estimate monthly bandwidth needed for your website or web app.
MB
/day
pages
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What Speed Do You Need?
Find the minimum internet speed for different activities.
Enter your connection speed to check compatibility
Mbps
Transfer Time
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seconds
Alt. Unit
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In Minutes
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Result
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Alt. Format
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File/Data
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Speed
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Breakdown
Speed Comparison
Understanding Bandwidth & Data
Bandwidth is the maximum rate of data transfer across a network, measured in bits per second (bps). File sizes are measured in bytes. Confusingly, 1 byte = 8 bits, so a 100 Mbps connection downloads at only 12.5 MB/s.
Key Formulas
Transfer time (seconds) = File size (bits) / Speed (bps)
File size in bits = File size (MB) × 8 × 1,000,000
1 byte = 8 bits
1 KB = 1,000 bytes (decimal) or 1,024 bytes (binary/KiB)
1 MB = 1,000 KB = 1,000,000 bytes
1 GB = 1,000 MB = 1,000,000,000 bytes
100 Mbps = 100,000,000 bps = 12.5 MB/s
Speed in MB/s = Speed in Mbps / 8
Why is my actual download speed lower than my plan speed?
Several factors reduce real-world speeds: (1) Network overhead: TCP/IP headers add ~10% overhead. (2) WiFi interference and distance from router. (3) ISP throttling or congestion during peak hours. (4) Server-side limitations — the host may not send at full speed. (5) Your device's hardware (old NIC, slow disk). A good rule of thumb: expect 70–80% of plan speed as real-world throughput on a wired connection, 50–70% on WiFi.
What is the difference between Mbps and MB/s?
Mbps = Megabits per second (lowercase 'b' = bits). MB/s = Megabytes per second (uppercase 'B' = bytes). Since 1 byte = 8 bits: MB/s = Mbps ÷ 8. A 100 Mbps connection transfers at 12.5 MB/s. Internet speeds are always advertised in Mbps. Download managers and file transfers show speeds in MB/s. This is one of the most common sources of confusion — always check whether you're looking at bits or bytes.
What is the difference between KB (kilobyte) and KiB (kibibyte)?
This is a definitional ambiguity: Decimal (SI): 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes (used by hard drive manufacturers and networking). Binary (IEC): 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes (used by operating systems). This is why a "500 GB" hard drive shows as ~465 GB in Windows — the OS uses binary prefixes. This calculator uses decimal (1 KB = 1,000 bytes) consistent with modern networking standards.
How much bandwidth does streaming use?
Video streaming is the biggest bandwidth consumer: SD (480p) ≈ 1–3 Mbps; HD (1080p) ≈ 5–8 Mbps; 4K ≈ 15–25 Mbps (Netflix uses ~15 Gbps for 4K). Audio streaming: ~0.5 Mbps at high quality. Video calls (Zoom 1080p): ~3 Mbps up and down. Online gaming: surprisingly low at ~1–3 Mbps, but needs low latency (under 50ms). For a household with multiple 4K streams and gaming, 200+ Mbps is recommended.