About this tool
How Video File Size Is Calculated
Video file size is determined by a simple formula: File Size = Bitrate × Duration / 8. The bitrate (measured in kilobits per second) represents how much data is used per second of video. Higher bitrates produce better quality but larger files. This calculator uses industry-standard bitrate profiles for each quality tier.
Understanding Video Quality Tiers
4K (2160p) uses approximately 35 Mbps and produces the highest quality suitable for large screens and professional work. 1080p (Full HD) at 8 Mbps is the standard for most content — it looks excellent on monitors and phones. 720p (HD) at 5 Mbps is ideal for streaming on slower connections. 480p (SD) at 2.5 Mbps is a data-saving option for mobile viewing.
File Format Comparison
MP4 (H.264 codec) is the universal standard — supported by every device and platform. WebM (VP9 codec) offers 20-30% smaller files but is primarily supported by Google/Android browsers. MKV is a flexible container that supports advanced features like multiple audio tracks and subtitles, commonly used for archival.
Bandwidth and Transfer Time
Transfer time depends on your internet speed. A 100 Mbps fiber connection transfers data at approximately 12.5 MB/s. A standard 4G/LTE connection averages about 5 MB/s. This calculator provides estimates for both scenarios so you can plan accordingly.
Storage Planning Tips
When planning video storage, add a 10-20% buffer above the estimated file size for metadata, thumbnails, and organizational files. For archival purposes, consider that 1 TB of storage can hold approximately 100 hours of 1080p video or 25 hours of 4K video.
Audio-Only Extraction
Extracting only the audio track dramatically reduces file size — typically by 90% or more. A 60-minute audio file at 320 kbps is approximately 140 MB, compared to 3.5 GB for the same duration at 1080p video. This is useful for podcasts, music, and lecture recordings.
Practical Usage Examples
4K Nature Documentary
Estimate storage for a 5-minute high-fidelity video.
Result: ~1.3 GB (MP4) | Transfer: ~1.7 min at 100 MbpsPodcast Episode (Audio)
Calculate size for a 60-minute audio recording.
Result: ~140 MB (MP3) | Transfer: ~12 sec at 100 MbpsSocial Media Clip
Quick estimate for a 60-second vertical video in 1080p.
Result: ~60 MB (MP4) | Transfer: ~5 sec on LTEStep-by-Step Instructions
Step 1: Enter Video Duration
Input the length of your video in minutes. This is the primary factor determining file size. For example, enter 10 for a 10-minute video.Step 2: Select Quality Level
Choose the video resolution: 4K (2160p) for cinematic quality, 1080p for Full HD, 720p for standard HD, 480p for SD, or Audio Only for extracting just the sound track.Step 3: Choose File Format
Select MP4 for universal compatibility (works on all devices), WebM for 20-30% smaller files (best on Android/Chrome), or MKV for advanced features like multiple audio tracks.Step 4: Review Your Estimate
The calculator shows three results: estimated file size, transfer time on different connection speeds, and the full technical profile including codec and bitrate information.Step 5: Plan Your Storage
Use these estimates to plan hard drive space, cloud storage budgets, or bandwidth requirements for your video projects.Core Benefits
Instant results with no waiting or processing delays
100% free to use with no sign-up, registration, or premium tiers
Complete privacy - all processing happens in your browser
Works offline once the page is loaded
Mobile-friendly responsive design for any device
No ads, pop-ups, or distractions
Bookmark-friendly for quick access anytime
Frequently Asked Questions
Estimates are based on standard constant-bitrate profiles and are typically accurate within 20-30%. Actual file sizes vary based on visual complexity — fast-motion scenes use more data than static shots due to variable bitrate encoding.
4K has 4 times the pixel count of 1080p (8.3 million vs 2.1 million pixels). While modern codecs are efficient, the raw data requirement is significantly higher, leading to file sizes 3-4x larger than 1080p.
MP4 (H.264 codec) is universally supported across all devices and platforms. WebM (VP9 codec) offers 20-30% smaller files at similar quality but has limited support outside Google/Android/Chrome ecosystems.
Yes. Select "Audio Only (MP3/M4A)" quality to estimate audio file sizes at 320 kbps. This is useful for podcasts, music extractions, and lecture recordings.
Multiply the single-video estimate by the number of videos in your library. For mixed-quality libraries, calculate each quality tier separately and sum the results.
Standard 1080p streaming uses 8-12 Mbps. For archival quality, 15-20 Mbps is recommended. This calculator uses 8 Mbps as the standard 1080p bitrate.
Yes. This video file size calculator is completely free. All calculations run locally in your browser — no data is sent to any server, and no account is required.