Bitrate calculator. File size and bitrate, both directions.
Calculate video file size from bitrate, or back out the bitrate you need for a target size. Compare against streaming-service standards in one place.
Calculations assume constant bitrate (CBR). Variable bitrate (VBR) encoding may produce different file sizes depending on content complexity.
The bitrate formula, both ways.
Bitrate is how much data a video uses per second, measured in megabits per second (Mbps). There are 8 bits in a byte, so:
file size (MB) = bitrate (Mbps) × duration (s) ÷ 8
bitrate (Mbps) = file size (MB) × 8 ÷ duration (s)Worked examples
- Bitrate to file size: 8 Mbps for 10 minutes (600 s) is 8 × 600 ÷ 8 = 600 MB.
- File size to bitrate: fitting 10 minutes into 500 MB needs 500 × 8 ÷ 600 ≈ 6.7 Mbps, shared between video and audio.
The calculator works in binary units (1 MB = 1,048,576 bytes), so its results differ by about 5% from the decimal math above: the first example shows as about 572 MB, and a 500 MB target works out to about 7.0 Mbps.
Want typical sizes by resolution and frame rate instead of a raw bitrate? Try the video file size calculator, or read how much storage iPhone video uses per minute.
Two levers, same dial.
More bits per second means more detail in each frame. 4K Netflix looks sharp at ~15 Mbps; the same content at 3 Mbps looks blocky. Beyond a threshold the eye can't tell, which is where efficient codecs like HEVC pay off.
The relationship is linear: double the bitrate, double the file size. A 10-minute clip at 8 Mbps is 600 MB; at 16 Mbps it's 1.2 GB. The trick is picking enough bitrate for your use case without paying for invisible detail.
| Resolution | Social | Streaming | High quality |
|---|---|---|---|
| 720p | 2-4 Mbps | 4-6 Mbps | 6-8 Mbps |
| 1080p | 4-6 Mbps | 6-10 Mbps | 10-15 Mbps |
| 4K | 15-25 Mbps | 20-35 Mbps | 35-60 Mbps |
HEVC achieves the same quality at roughly half these numbers.
Common questions.
- How do I calculate file size from bitrate?
- Multiply the bitrate in Mbps by the duration in seconds and divide by 8. A 10-minute clip at 8 Mbps is 8 × 600 ÷ 8 = 600 MB.
- How do I calculate the bitrate for a target file size?
- Multiply the target size in MB by 8, then divide by the duration in seconds. To fit 10 minutes into 500 MB you need about 500 × 8 ÷ 600 = 6.7 Mbps in total, including audio.
- What bitrate does Netflix use for 4K?
- Netflix streams 4K at about 15-16 Mbps using HEVC. YouTube uses up to 35 Mbps for 4K with VP9. Netflix achieves comparable quality at lower bitrate thanks to its tuned encoding pipeline.
- What bitrate should I upload to YouTube?
- YouTube recommends 8 Mbps for 1080p and 35-45 Mbps for 4K. YouTube re-encodes everything, so uploading at higher bitrates gives the platform more headroom and yields better final quality.
- Does higher bitrate always mean better quality?
- Not always. Beyond a threshold there's no visible improvement. The threshold depends on resolution and content: fast action needs more bitrate than a static interview shot.
- What's the difference between Mbps and MBps?
- Mbps (megabits per second) is the usual unit for video bitrate. MBps (megabytes per second) is common for file and transfer sizes. 1 MBps = 8 Mbps.
- How does HEVC reduce bitrate needs?
- HEVC uses smarter motion prediction and block partitioning. It delivers similar perceived quality to H.264 at roughly half the bitrate, cutting file sizes by about 50%.
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