Bitrate Calculator

About Bitrate Calculator

How the Bitrate Formula Works

The core relationship is straightforward: File Size (bits) = Bitrate (bits per second) x Duration (seconds). Since file sizes use bytes and bitrates use bits, divide by 8 to convert bits to bytes.

Worked example: A 2-hour recording at 8 Mbps (YouTube 1080p upload bitrate). First, convert to seconds: 2 hours = 7,200 seconds. Then multiply: 8,000,000 bits/sec x 7,200 sec = 57,600,000,000 bits. Divide by 8 to get bytes: 7,200,000,000 bytes = 7.2 GB. That is your estimated file size before compression.

The calculator handles three modes depending on which value you need:

Mode	You Know	You Get	Use Case
Bitrate + Duration	Bitrate (e.g. 25 Mbps) and duration (e.g. 2 hours)	Estimated file size	Planning storage for a recording session
File Size + Duration	Target file size (e.g. 4.7 GB) and duration (e.g. 2 hours)	Required bitrate	Encoding to fit a specific storage limit like a DVD
File Size + Bitrate	File size and known bitrate	Playback duration	Estimating how long a downloaded media file will play

Video Streaming and Upload Bitrates

Every major streaming platform and upload service has recommended bitrate ranges. These numbers determine both video quality and how much storage or bandwidth a video consumes.

Platform / Format	Resolution	Recommended Bitrate	1 Hour File Size
YouTube upload	1080p 30fps	8 Mbps	~3.6 GB
YouTube upload	1080p 60fps	12 Mbps	~5.4 GB
YouTube upload	4K 30fps	35-45 Mbps	~15.75-20.25 GB
YouTube upload	4K 60fps	53-68 Mbps	~23.85-30.6 GB
Netflix streaming	SD (480p)	~0.7 Mbps	~300 MB
Netflix streaming	HD (1080p)	~5 Mbps	~2.25 GB
Netflix streaming	4K HDR	~15-25 Mbps	~7 GB
Twitch live stream	1080p 60fps	6,000 kbps (max)	~2.7 GB
Blu-ray disc	1080p	Up to 40 Mbps	~18 GB
4K UHD Blu-ray	2160p	Up to 128 Mbps	~57.6 GB

YouTube's recommended upload bitrates come from Google's official encoding guidelines. YouTube re-encodes every upload, so uploading at a higher bitrate preserves more detail through that process. Netflix uses adaptive bitrate streaming, meaning the actual rate adjusts based on your connection speed - the numbers above are typical peak rates. Twitch enforces a hard cap of 6,000 kbps for all streamers. Standard Blu-ray supports up to 40 Mbps total (video plus audio), while 4K UHD Blu-ray supports up to 128 Mbps using HEVC/H.265 compression (Blu-ray Disc Association specification).

Audio Bitrate Reference

Audio files and streams use much lower bitrates than video, but the same formula applies. Here are the common formats and quality tiers:

Service / Format	Quality Tier	Bitrate	1 Hour File Size
Spotify Free	Normal	96 kbps (Ogg Vorbis)	~43 MB
Spotify Free	High (max for free)	160 kbps	~72 MB
Spotify Premium	Very High	320 kbps (Ogg Vorbis)	~144 MB
Spotify Premium	Lossless (since Sep 2025)	~1,411 kbps (FLAC)	~635 MB
Apple Music	Lossless	~1,411 kbps (ALAC 16-bit/44.1kHz)	~635 MB
Apple Music	Hi-Res Lossless	Up to ~9,216 kbps (ALAC 24-bit/192kHz)	~4.15 GB
CD Audio (PCM)	Uncompressed	1,411 kbps	~635 MB

The CD audio bitrate of 1,411 kbps comes directly from its specification: 44,100 samples per second x 16 bits per sample x 2 channels (stereo) = 1,411,200 bits per second. This is uncompressed PCM audio. Lossy codecs like Ogg Vorbis (Spotify) and AAC (Apple) compress this down to 128-320 kbps by discarding audio data that most listeners cannot hear.

Bits vs Bytes - Why the Difference Matters

Bitrate uses bits per second (bps), but file sizes and storage use bytes. There are 8 bits in 1 byte. This distinction catches people out regularly because internet speeds are advertised in bits (Mbps) while downloads show bytes (MB/s).

Unit	Symbol	Typical Use	Conversion
Kilobits per second	kbps	Audio bitrates, low-bandwidth streams	1 kbps = 125 bytes/sec
Megabits per second	Mbps	Video bitrates, broadband speeds	1 Mbps = 125 KB/sec
Gigabits per second	Gbps	Fibre connections, data centre links	1 Gbps = 125 MB/sec
Megabytes	MB	File sizes, app sizes	1 MB = 8 Megabits
Gigabytes	GB	Storage, large downloads	1 GB = 8 Gigabits

A practical example: a 100 Mbps internet connection can transfer 100/8 = 12.5 MB per second. A 7 GB Netflix 4K movie would take about 7,000/12.5 = 560 seconds, or roughly 9.3 minutes to download at full speed. The file transfer time calculator handles these calculations across all common connection types.

How Video Codecs Affect Real File Sizes

The calculator produces a constant bitrate (CBR) estimate, but real video files almost always use variable bitrate (VBR) encoding through a specific codec. The codec matters because newer codecs compress more efficiently, producing smaller files at the same visual quality.

Codec	Typical 1080p Bitrate	Efficiency vs H.264	Common Use
H.264 (AVC)	4,500-6,000 kbps	Baseline	Older devices, broad compatibility
H.265 (HEVC)	2,250-3,000 kbps	~50% smaller	4K Blu-ray, Apple devices, newer streaming
AV1	1,800-2,400 kbps	~50-60% smaller	YouTube, Netflix (newer content), Twitch (2026)
VP9	2,500-3,500 kbps	~35-45% smaller	YouTube (legacy), Google services

H.265 roughly halves the bitrate needed compared to H.264 for the same quality. AV1 improves on that by another 20-30%, meaning a 4,000 kbps AV1 stream can match a 6,000 kbps H.264 stream visually. AV1 is also royalty-free, unlike H.265 which requires licensing from three separate patent pools. YouTube, Netflix, and Twitch are all actively rolling out AV1 support. If you are encoding with a newer codec, expect actual file sizes to be 30-50% smaller than what this calculator estimates using raw bitrate alone.

Variable vs Constant Bitrate Encoding

Type	How It Works	File Size Predictability	Quality Behaviour
CBR (Constant)	Same bitrate every second	Predictable (this calculator assumes CBR)	Wastes bits on simple scenes, may lack bits for complex ones
VBR (Variable)	Adjusts per-frame based on complexity	Less predictable, typically smaller than CBR at same quality	More bits for complex scenes, fewer for static ones
ABR (Average)	Targets an average but varies moment to moment	Close to predicted but not exact	Compromise between CBR predictability and VBR efficiency

Nearly all modern video uses VBR or ABR encoding. A fast-action scene with lots of motion needs more data than a static title card. VBR encoding allocates bits where they are needed most, so actual file sizes are typically 5-15% different from a CBR estimate. For rough storage planning, the CBR estimate from this calculator is close enough. For precise encoding targets, use a two-pass VBR encode and measure the output.

Common Mistakes When Estimating File Size

A few things regularly trip people up when estimating media file sizes:

Forgetting audio tracks. Video bitrate is usually quoted alone, but a typical video file also contains an audio track at 128-320 kbps. For short clips this is negligible, but for long recordings it adds up. A 2-hour video with 256 kbps audio adds about 230 MB on top of the video data.

Confusing bits and bytes. An "8 Mbps" stream does not produce 8 MB per second of data. It produces 1 MB per second because there are 8 bits in a byte. This is the single most common source of confusion.

Ignoring container overhead. Real files include metadata, chapter markers, subtitle tracks, and container formatting (MP4, MKV, WebM). This typically adds 1-3% to the raw audio/video data size.

Using upload bitrate for streaming estimates. YouTube recommends uploading at 8 Mbps for 1080p, but it re-encodes and streams at a lower rate (typically 3-5 Mbps for 1080p playback). The upload bitrate is intentionally higher to give YouTube more data to work with during re-encoding.

How Much Storage Does Streaming Actually Use?

Streaming data consumption is one of the most practical applications of bitrate calculations. Here is what common streaming activities consume per hour, based on published platform data:

Activity	Typical Bitrate	Data Per Hour	Data Per 2h Movie
Spotify (Normal quality)	96 kbps	~43 MB	~86 MB
Spotify (Very High / Premium)	320 kbps	~144 MB	~288 MB
Netflix SD (480p)	~0.7 Mbps	~300 MB	~600 MB
Netflix HD (1080p)	~5 Mbps	~2.25 GB	~4.5 GB
Netflix 4K HDR	~15-25 Mbps	~7 GB	~14 GB
YouTube 1080p playback	~3-5 Mbps	~1.35-2.25 GB	~2.7-4.5 GB
YouTube 4K playback	~15-20 Mbps	~6.75-9 GB	~13.5-18 GB
Twitch 1080p60 stream	6,000 kbps	~2.7 GB	~5.4 GB

Netflix's data figures come from its official help centre (help.netflix.com). The service uses adaptive bitrate streaming, so actual consumption varies based on your connection. Newer codecs like HEVC and AV1 (now used by Netflix for much of its catalogue) deliver the same quality at 30-50% lower bitrates than older H.264 encoding. This means a Netflix 4K stream in 2026 uses significantly less data than the same content would have a few years ago.

For a household with limited broadband or a mobile data cap, these numbers matter. Watching 2 hours of Netflix 4K content per day uses roughly 420 GB per month - enough to blow through many home broadband fair-use policies. Dropping to 1080p cuts that to about 135 GB per month.

Storage Planning for Recordings

Content creators and security camera operators need to plan storage around expected bitrate and recording duration. A quick reference for common scenarios:

Security cameras: A single 1080p IP camera at 4 Mbps (a typical setting) produces about 1.8 GB per hour. Running 24/7, that is 43.2 GB per day or roughly 1.3 TB per month per camera. Four cameras at the same bitrate need about 5.2 TB per month.

Podcast recording: Uncompressed WAV audio at CD quality (1,411 kbps) produces about 635 MB per hour. A typical 1-hour weekly podcast recorded in stereo WAV generates about 2.5 GB per month of raw audio. After compressing to 128 kbps MP3 for distribution, the final files are about 57 MB per episode.

Video production: Shooting in 4K at 100 Mbps (common for cameras like the Sony A7 series and Blackmagic Pocket) produces 45 GB per hour. A full day of shooting (8 hours of footage) generates about 360 GB of raw files, which is why professional videographers carry multiple fast SD cards or SSDs.

For converting between storage units like KB, MB, GB, and TB, the storage unit converter handles all common conversions. To estimate how much video footage fits on a drive, try the video storage calculator which factors in resolution and frame rate.

Sources

• Netflix Help Center - Internet connection speed recommendations
• YouTube Help - Recommended upload encoding settings (bitrates)
• Twitch - Broadcast guidelines (bitrate and resolution)
• ITU-T H.264 - Advanced Video Coding specification
• ITU-T H.265 - High Efficiency Video Coding (HEVC) specification
• Alliance for Open Media - AV1 codec specification