Video File Size Calculator
Knowing how large your video files will be before you shoot or export is essential for planning storage, estimating upload times, and choosing the right codec for your workflow. Video file size is determined by two factors: bitrate (the amount of data encoded per second, measured in megabits per second or Mbps) and duration. A higher bitrate means better image quality but larger files. The codec also makes a major difference: H.265/HEVC achieves roughly the same quality as H.264 at half the bitrate, while professional formats like Apple ProRes 422 use very high bitrates to preserve every detail for editing. The formula is straightforward: multiply the bitrate in bits per second by the duration in seconds, then divide by 8 to convert bits to bytes. The result is the raw estimated file size in bytes, which you then convert to megabytes or gigabytes for practical planning. This calculator covers the most common formats, from 480p web video to 4K RAW cinema, and shows you how many minutes of footage fit on 128 GB, 256 GB, and 1 TB of storage. Select a preset resolution and codec, or enter a custom bitrate for any format not listed.
Estimated file size: -- GB
How video file size is calculated
The estimated file size in bytes is calculated from the bitrate and duration. Bitrate is expressed in megabits per second (Mbps). One megabit equals 1,000,000 bits. Dividing by 8 converts bits to bytes.
bytes = (bitrate_mbps × 1,000,000 × duration_seconds) / 8
megabytes = bytes / 1,048,576
gigabytes = bytes / (1,048,576 × 1,024)
terabytes = bytes / (1,048,576 × 1,024 × 1,024)
Worked example: 10 minutes of 1080p H.264 at 8 Mbps
- Duration = 10 min × 60 = 600 seconds
- Bits = 8,000,000 bits/s × 600 s = 4,800,000,000 bits
- Bytes = 4,800,000,000 / 8 = 600,000,000 bytes
- Megabytes = 600,000,000 / 1,048,576 = approximately 572 MB
- Gigabytes = 572 / 1,024 = approximately 0.56 GB
Note: this calculator uses binary megabytes (1 MB = 1,048,576 bytes) consistent with how operating systems report file sizes. Some manufacturers use SI megabytes (1 MB = 1,000,000 bytes), which would give slightly larger numbers.
Video format reference: file size by codec
Estimates below use binary gigabytes (1 GB = 1,073,741,824 bytes).
| Format | Bitrate | 1 minute | 1 hour |
|---|---|---|---|
| 1080p H.264 | 8 Mbps | 57.22 MB | 3.44 GB |
| 4K H.265/HEVC | 25 Mbps | 178.81 MB | 10.73 GB |
| 4K H.264 | 50 Mbps | 357.63 MB | 21.46 GB |
| 4K ProRes 422 | 500 Mbps | 3.49 GB | 214.58 GB |
Actual file sizes will vary by encoder, container overhead, audio tracks, and metadata. Audio typically adds 0.128 to 0.320 Mbps for stereo AAC or PCM tracks, a small addition except for very short clips.
Video file size calculator: frequently asked questions
What bitrate should I use for YouTube?
YouTube recommends different bitrates depending on resolution and frame rate. For 1080p at 30 fps, YouTube recommends 8 Mbps (SDR) or 12 Mbps (HDR). For 4K at 30 fps, YouTube recommends 35 to 45 Mbps (SDR) or 44 to 56 Mbps (HDR). For 4K at 60 fps, the recommended range is 53 to 68 Mbps. These figures apply to H.264 uploads. H.265 and VP9 encode the same quality at roughly half the bitrate, but YouTube re-encodes uploaded files, so the upload bitrate determines the source quality, not the final delivery bitrate. See the official YouTube support page for the current recommended upload encodings.
How much storage do I need for 4K video?
Storage requirements for 4K video depend heavily on the codec and bitrate. At a typical 4K H.265 bitrate of 25 Mbps, one hour of video requires approximately 11.3 GB. At 4K H.264 (50 Mbps), one hour needs around 22.5 GB. Professional formats are much larger: 4K ProRes 422 at 500 Mbps uses roughly 225 GB per hour. For everyday 4K filming on a camera, plan for approximately 10 to 25 GB per hour with modern codecs, or 100 to 500 GB per hour for professional cinema workflows.
What is the difference between H.264 and H.265?
H.264 (AVC, Advanced Video Coding) and H.265 (HEVC, High Efficiency Video Coding) are video compression standards. H.265 is the newer standard and achieves roughly double the compression efficiency: it can encode the same visual quality as H.264 at approximately half the file size and bitrate. The trade-off is that H.265 requires more processing power to encode and decode. H.264 has near-universal compatibility across devices and platforms, while H.265 support, though widespread, is not yet universal. Both are lossy codecs that discard information to reduce file size.
What is ProRes and when should I use it?
ProRes is a family of high-quality, intra-frame video codecs developed by Apple, widely used in professional post-production workflows. Unlike H.264 and H.265, which use inter-frame compression (comparing frames to reduce redundancy), ProRes compresses each frame independently, making editing much faster and more accurate since every frame is a complete picture. ProRes 422 and ProRes 4444 are the most common variants. The trade-off is very large file sizes: 4K ProRes 422 uses around 500 Mbps, compared to 25 Mbps for 4K H.265. ProRes is used when editing quality matters more than storage efficiency.
How does bitrate affect video quality?
Bitrate is the amount of data used per second of video. Higher bitrate preserves more detail, reduces compression artifacts (such as blocking and banding), and results in better image quality, especially in fast-moving or high-detail scenes. Lower bitrate reduces file size but can introduce visible quality loss. The relationship between bitrate and quality also depends on the codec: H.265 can match H.264 quality at half the bitrate. Resolution also matters: encoding a 4K image at a bitrate suited for 1080p will produce poor quality because there is insufficient data to represent the higher resolution. Use the bitrate figures recommended by the platform or device manufacturer as a starting point.
Official sources
- YouTube recommended upload encodings: support.google.com/youtube/answer/1722171.
- Bit rate overview: Wikipedia: Bit rate.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.