About

In the digital imaging pipeline, accuracy is not a luxury; it is a logistical necessity. Whether you are a Digital Imaging Technician (DIT) managing on-set data, a post-production supervisor planning server capacity, or a streamer optimizing for Twitch limits, guessing file sizes leads to disaster. A miscalculation can result in running out of drive space mid-shoot or a failed upload due to platform caps.

This tool goes beyond simple multiplication. It incorporates a comprehensive database of industry standards, from highly compressed H.265 streaming codecs to uncompressed ARRIRAW and RedCode ratios. It accounts for audio channel multitracking (5.1, 7.1, Atmos), container overhead, and bit-depth variations. Use this to determine exactly how many Terabytes of storage your feature film needs or if your 1080p stream will bottleneck your home internet connection.

Formulas

The core calculation for digital video size involves summing the video and audio data rates and multiplying by time. However, professional calculations must account for the number of audio channels and container overhead.

{

S_MB = (R_v + (R_a × N_ch)) × t8 × 1024 × (1 + O)Where:S_MB = File size in MegabytesR_v = Video bitrate (kbps)R_a = Audio bitrate per channel (kbps)N_ch = Number of audio channelst = Duration in secondsO = Overhead coefficient (e.g. 0.02 for 2%)

For uncompressed PCM audio (common in ProRes/DNxHR), the audio bitrate R_a is calculated as:

R_a = f_s × d_bit

where f_s is the sample rate (e.g., 48kHz) and d_bit is the bit depth (e.g., 24-bit).

Reference Data

Format / Codec	Resolution & Profile	Target Bitrate (Mbps)	Storage/Hour (GB)
ProRes 4444 XQ	4K UHD (3840x2160) 24fps	1697 Mbps	764.0 GB
ProRes 422 HQ	4K UHD (3840x2160) 24fps	754 Mbps	339.0 GB
DNxHR HQX	4K DCI (4096x2160) 24fps	728 Mbps	327.0 GB
REDCODE RAW	8K 8:1 Compression	1600 Mbps	720.0 GB
ARRIRAW	Open Gate 3.4K 30fps	2600 Mbps	1170.0 GB
Sony XAVC I	Class 300 (4K)	300 Mbps	135.0 GB
Canon XF-AVC	Intra 4K 4:2:2	410 Mbps	184.5 GB
H.265 (HEVC)	Main 10 4K High Quality	45 - 60 Mbps	27.0 GB
YouTube	2160p (4K) HDR 60fps	85 Mbps	38.2 GB
YouTube	1080p Standard 30fps	8 Mbps	3.6 GB
Twitch	1080p Source (CBR limit)	6 Mbps	2.7 GB
Netflix	4K UHD (High Profile)	16 Mbps	7.2 GB
Blu-ray Disc	Standard 1080p	40 Mbps (Max)	18.0 GB
Zoom Recording	HD Cloud Record	1.2 Mbps	0.54 GB

Frequently Asked Questions

This is the most common error in storage planning. Mbps (Megabits per second) is the speed of the data stream, used by cameras and encoders. MB/s (Megabytes per second) is the writing speed of your hard drive. There are 8 bits in 1 byte. Therefore, a camera shooting 400 Mbps requires a card capable of writing at least 50 MB/s.

ProRes and DNxHR are "Intermediate Codecs" using Intra-frame compression. Every single frame is saved as a complete image, making them easy for computers to edit but heavy on storage. H.264/H.265 are "Delivery Codecs" using Inter-frame compression (IBP), saving only the changes between frames, which saves space but requires more processing power to decode.

Resolution dictates the *preset* bitrate (e.g., 4K requires more bitrate than 1080p for clear image), but the math relies solely on the Bitrate. If you manually force a 4K video to 5 Mbps and a 1080p video to 5 Mbps, they will be the same file size (though the 4K version will be full of artifacts).

Streaming platforms re-encode your video. The presets here calculate the file size *you upload* to them. If you follow YouTube's recommended settings for 4K (85 Mbps), your file will be large. After YouTube processes it, the version viewers watch will be much smaller (VP9/AV1 codec), but you still need the bandwidth to upload the master file.

A video file (MP4, MOV, MXF) acts as a box holding video and audio streams. The box itself has labels, timecode tracks, and metadata. This typically adds 1-2% to the file size. For complex formats like DCP or fragmented MP4s, it can be slightly higher.