File Size Calculator
Estimate raw file size from parameters - image dimensions and color depth, or audio/video bitrate and duration.
Choose image or audio/video mode and enter the relevant parameters - this tool estimates the resulting raw file size.
Decimal uses 1000-based multiples (kB/MB/GB/TB); Binary uses 1024-based multiples (KiB/MiB/GiB/TiB). Switch the convention to see both interpretations - the same raw byte count is used, only the unit labels/divisors change.
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View all 19This estimates uncompressed/raw size based on the math - real compressed files (JPEG, MP4, MP3) are typically much smaller due to compression, which this calculator doesn't attempt to simulate.
How This Differs from a Unit Converter
Rather than converting an already-known size between units (see the Byte Converter for that), this tool estimates what a file's size will be from its underlying parameters - useful when planning before you've actually created the file.
How to Use It
- Choose Image mode (enter width, height, and color depth) or Audio/Video mode (enter bitrate and duration).
- View the estimated raw file size.
Important Notes
This calculates uncompressed size based on raw math (width × height × bytes-per-pixel for images; bitrate × duration for audio/video) - actual compressed file formats (JPEG, PNG, MP4, MP3) apply compression that significantly reduces real file size, which varies by content and isn't something this calculator can predict.
Worked Examples
Image: a 4000 × 3000 photo at 24-bit colour (3 bytes per pixel) is 4000 × 3000 × 3 = 36,000,000 bytes, about 36 MB uncompressed. Saved as a JPEG, the same photo is typically 3-6 MB.
Audio: 60 minutes of MP3 at 128 kbps is 128,000 bits/s × 3,600 s ÷ 8 = 57,600,000 bytes, about 57.6 MB.
Video: a 10-minute video at 8 Mbps is 8,000,000 × 600 ÷ 8 = 600,000,000 bytes, about 600 MB.
When This Is Useful
- Checking whether a recording will fit a platform's upload limit before you record it.
- Choosing a bitrate that keeps a video under a target size.
- Estimating memory needed to process images, since images are uncompressed in memory.
Why Compressed Files Differ
Audio and video bitrates already describe the compressed stream, so those estimates are close to the real file size. Image formats compress by very different amounts - PNG screenshots with flat colours compress well, noisy photos much less - so treat image results as the upper bound.
Plan space for many files with the Storage Calculator, estimate transfers with the Download Time Calculator, and shrink images with the WebP Converter.
Frequently Asked Questions
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