Download time calculator
For the transfer time of one file at a stated connection speed.
17 tools
Computer calculators
Practical calculations for the digital world: how long a file takes on your link, how much bandwidth all your users need, how many milliseconds go into a frame and how a resolution reduces to an aspect ratio. Bits and bytes, decimal and binary prefixes are kept explicitly apart rather than hidden in a coefficient.
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Aspect ratio calculator
Reduce a resolution to its ratio, or find the missing side.
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Computer calculators
HEX, RGB and HSL colour converter
Convert a colour from HEX to RGB and HSL with a per-channel breakdown.
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CSS units converter
Convert px, rem, em, pt and the other CSS length units.
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Computer calculators
Download time calculator
How long a file takes on your connection, bits and bytes kept apart.
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Files on disk calculator
How many files of a given size fit on a drive.
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FPS to frame time calculator
Convert between frames per second and milliseconds per frame.
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Internet data usage calculator
How many gigabytes a month adds up to at a given stream rate and hours per day.
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IPv4 subnet calculator
Network address, mask, broadcast address and host count from CIDR notation.
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Modular scale calculator
Typographic sizes from a base and a ratio, with a table of steps.
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Network bandwidth calculator
Estimate bandwidth from total users, their active share and explicit headroom.
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Password entropy calculator
Entropy of a uniformly random sequence and a search model at the supplied rate.
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PPI calculator
Screen pixel density from the resolution and the diagonal.
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RAID calculator
Usable capacity of a RAID array, its failure tolerance and the efficiency of each level.
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Word and character counter
Words, characters with and without spaces, sentences and paragraphs in one pass.
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TV viewing distance calculator
Geometric distances for 40°/30° screen angles and an assumed 1′ pixel.
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Computer calculators
Unix timestamp converter
Convert between Unix time and a UTC date, both directions.
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Computer calculators
Video file size calculator
Recording size from video and audio bitrate — in gigabytes and mebibytes.
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Which calculation to choose
Network bandwidth calculator
For aggregate bandwidth required by several simultaneous users or streams.
What to prepare
Check file size, speed units and simultaneous active connections. Account for network overhead separately.
Common mistake
One byte contains eight bits. A theoretical link speed does not guarantee that file download speed.
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FAQ
What is the difference between a megabyte and a mebibyte?
A megabyte is a million bytes; a mebibyte is 1,048,576 bytes. The gap is about five percent and shows on large files, so the unit is chosen explicitly.
Why is link speed in bits but file size in bytes?
History: providers measure links in bits per second while files are stored in bytes. One byte is eight bits, and the calculator converts for you.
Is protocol overhead included?
No. The calculation is deterministic: real throughput is usually lower, and a margin can be added in a separate field where one is provided.
Why does 2560×1080 give 64:27 rather than 21:9?
The exact ratio comes from dividing by the greatest common divisor. "21:9" is a marketing round number, not the reduced ratio.
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