Video file size equals the combined video and audio bitrate multiplied by the duration in seconds, divided by 8 to convert bits to bytes. A 10-minute 1080p H.264 video at 10 Mbps produces roughly 750 MB. Use the free estimator below to calculate exact file sizes for any resolution, codec, duration, and audio quality setting.
Key Takeaways
- File size formula: (Video bitrate + Audio bitrate) x Duration in seconds / 8 = File size in megabytes.
- Resolution impact: 4K video at 40 Mbps produces 8x larger files than 720p at 5 Mbps for the same duration.
- Codec matters: H.265 reduces file size by 40% compared to H.264 at equivalent visual quality.
- ProRes warning: ProRes 422 files are 3x larger than H.264. A 10-minute 1080p ProRes file reaches 2.25 GB.
- 1 hour of 4K H.264: Approximately 18 GB. Plan storage and upload bandwidth accordingly.
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What Determines Video File Size?
Video file size is determined by bitrate, duration, codec, and audio quality combined through a simple multiplication formula.
Bitrate measures how much data is processed per second of video. A 1080p video at 10 Mbps (megabits per second) processes 10 million bits every second. Multiply that by the total seconds, divide by 8 to convert bits to bytes, and you have your file size.
Four variables control the final number. Resolution sets the baseline bitrate requirement: 720p needs roughly 5 Mbps, 1080p needs 10 Mbps, 1440p needs 20 Mbps, and 4K needs 40 Mbps. The codec applies a compression multiplier that either shrinks or expands that baseline. Duration scales linearly. Audio adds a small but consistent overhead of 128–320 kbps depending on quality. Change any one of these variables and the file size shifts proportionally.
How Does Video Codec Affect File Size?
Your codec choice can halve or triple your file size at identical visual quality.
H.264 is the universal standard and serves as the 1.0x baseline. Most cameras, editing software, and streaming platforms support it natively. H.265 (HEVC) achieves the same visual quality at 40% smaller file sizes, using a 0.6x multiplier. A 1 GB H.264 file becomes 600 MB in H.265 with no visible quality loss.
VP9, developed by Google, compresses to 0.7x of H.264. YouTube re-encodes uploads to VP9 automatically, which is why YouTube videos stream efficiently. ProRes 422 sits at the opposite end at 3.0x. It is an editing codec designed for post-production workflows where every frame must decode instantly. A 10-minute 1080p ProRes file reaches 2.25 GB compared to 750 MB for H.264. Only use ProRes for editing timelines, never for delivery or upload.
How Much Storage Does 1 Hour of Video Need?
One hour of 1080p H.264 video at 10 Mbps requires approximately 4.5 GB of storage.
Here are the exact figures for common configurations. One hour of 720p at 5 Mbps: 2.25 GB. One hour of 1080p at 10 Mbps: 4.5 GB. One hour of 1440p at 20 Mbps: 9 GB. One hour of 4K at 40 Mbps: 18 GB. These assume H.264 encoding with 256 kbps audio.
Switch to H.265 and those numbers drop by 40%. One hour of 4K H.265 shrinks to roughly 10.8 GB. Switch to ProRes for editing and they triple: one hour of 1080p ProRes reaches 13.5 GB. A typical wedding videographer shooting 6 hours of 4K ProRes footage generates over 80 GB of raw files per event. Planning storage around these numbers prevents mid-shoot card failures and post-production bottlenecks.
How Long Does It Take to Upload Video Files?
Upload time equals your file size in megabits divided by your upload speed in megabits per second.
A 4.5 GB file (one hour of 1080p H.264) contains 36,000 megabits. On a 10 Mbps upload connection, that takes 60 minutes. On 50 Mbps, it takes 12 minutes. On 100 Mbps fibre, it takes 6 minutes.
Real-world speeds are typically 70–80% of advertised upload speeds due to network overhead and congestion. If your ISP advertises 50 Mbps upload, expect 35–40 Mbps sustained. For regular video uploads to YouTube, Vimeo, or client delivery platforms, 50 Mbps upload or higher makes a material difference. Uploading a 4K project file at 18 GB on a 10 Mbps connection takes 4 hours. The same file on 100 Mbps takes 24 minutes. Factor upload time into your delivery deadlines, especially for same-day turnaround projects.
What Bitrate Should You Use for Different Resolutions?
Use 5 Mbps for 720p, 10 Mbps for 1080p, 20 Mbps for 1440p, and 35–45 Mbps for 4K as starting points.
These defaults suit most content types. Fast-motion content like sports, gaming, and action sequences benefits from 20–50% higher bitrates to avoid compression artefacts during rapid scene changes. Talking-head videos and presentations can reduce bitrate by 30–40% below these defaults because static scenes compress more efficiently.
YouTube recommends 8 Mbps for 1080p SDR uploads and 35–45 Mbps for 4K SDR. These recommendations assume H.264 encoding. If you export in H.265, you can use 60% of those bitrates and maintain equivalent quality. For archival or master copies, use 1.5x the standard bitrate. For social media delivery where platforms re-encode aggressively, standard bitrates are sufficient because the platform compresses everything to its own target regardless of your source quality.
How Should You Plan Storage for Video Projects?
Budget 3x your estimated raw footage size to account for project files, renders, and backup copies.
A 30-minute final video typically requires 2–4 hours of raw footage. At 1080p H.264, that means 9–18 GB of raw files. Add editing project files (1–3 GB), render exports in multiple formats (5–10 GB), and one backup copy, and your total project footprint reaches 25–50 GB.
For 4K workflows, multiply everything by 4. A single 30-minute 4K project can consume 100–200 GB when accounting for raw footage, proxies, project files, and deliverables. Use the calculator above to estimate individual file sizes, then multiply by your expected shoot ratio. Most professionals maintain at least 2 TB of fast SSD storage for active projects and archive completed work to cheaper HDD or cloud storage. The 3-2-1 backup rule applies: 3 copies, 2 different media types, 1 offsite.
Does Audio Bitrate Make a Noticeable Difference to File Size?
Audio adds 0.1–0.3% to total file size at video bitrates above 5 Mbps, making it negligible for most calculations.
At 256 kbps (0.256 Mbps), audio adds roughly 1.9 MB per minute. Over a 10-minute video at 1080p (750 MB total), audio accounts for just 19 MB or 2.5% of the file. At 4K bitrates, audio becomes even less significant percentage-wise.
Where audio bitrate matters is in podcast video, music production, and ASMR content where audio quality is the primary deliverable. For these formats, use 320 kbps AAC or uncompressed WAV audio. For standard YouTube content, 192–256 kbps provides transparent quality that listeners cannot distinguish from higher bitrates in blind tests. The file size difference between 128 kbps and 320 kbps audio is approximately 1.4 MB per minute, totally irrelevant for video delivery but worth considering for audio-only podcast files.
Frequently Asked Questions
Why is my exported file larger than the calculator estimate?
Export software uses variable bitrate (VBR) encoding by default, which can spike above the target bitrate during complex scenes. The calculator uses constant bitrate (CBR) as a baseline. VBR files average close to the target but individual segments can exceed it by 20–50%. Container overhead from MP4 or MOV wrappers adds another 1–2%.
What is the smallest file size for acceptable 1080p quality?
A 1080p video at 4–5 Mbps with H.265 encoding delivers acceptable quality for web streaming. That produces roughly 300–375 MB per 10 minutes. Below 3 Mbps, you will notice blockiness in high-motion scenes. For static content like presentations, 2 Mbps H.265 at 1080p remains watchable, producing just 150 MB per 10 minutes.
Does frame rate affect file size?
Frame rate does not directly change file size when bitrate is fixed. The encoder distributes the same bitrate across more frames, giving each frame less data. However, higher frame rates need higher bitrates to maintain quality. A 60fps video should use 1.5x the bitrate of 30fps content for equivalent per-frame quality, which increases file size by 50%.
How much space does a 1-hour Zoom recording take?
Zoom records locally at approximately 200–300 MB per hour for a standard 1080p meeting with gallery view. Cloud recordings compress more aggressively at 100–150 MB per hour. These are lower than standard video bitrates because Zoom uses aggressive compression optimised for screen content and talking heads.
Should I upload in 4K to YouTube if I filmed in 4K?
Yes. Even though most viewers watch at 1080p, YouTube allocates a higher bitrate codec (VP9 instead of AVC) to videos with 4K source files. Your 1080p viewers actually see better quality from a 4K upload than from a 1080p upload. The upload takes longer but the quality improvement is visible.
What file size limit does YouTube have?
YouTube allows uploads up to 256 GB or 12 hours, whichever limit is reached first. Verified accounts get the full limit. Unverified accounts are restricted to 15 minutes. Most 4K content at standard bitrates stays well within the 256 GB limit unless you upload extremely long raw footage.
How do I calculate file size for a live stream recording?
Live stream recordings use the same formula as standard video. Multiply your streaming bitrate by the duration. Most platforms stream at 4,500–6,000 kbps for 1080p. A 3-hour stream at 6 Mbps produces approximately 8.1 GB. The recording file may differ slightly from the estimate because live encoders use variable bitrate to adapt to network conditions in real time.
What is the difference between bitrate and file size?
Bitrate measures data rate per second (megabits per second). File size is the total data stored on disk (megabytes or gigabytes). To convert: multiply bitrate by duration in seconds, then divide by 8 to convert bits to bytes. A 10 Mbps video running for 600 seconds produces 10 x 600 / 8 = 750 megabytes. Bitrate determines quality. File size determines storage needs.
Does colour depth (8-bit vs 10-bit) affect file size?
At the same bitrate setting, 8-bit and 10-bit video produce identical file sizes because the bitrate cap controls the output. However, 10-bit content benefits from 20–30% higher bitrates to preserve the additional colour information. If you increase bitrate to accommodate 10-bit, file sizes grow proportionally. HDR content, which requires 10-bit, typically needs 25–40% higher bitrates than SDR for equivalent perceptual quality.
Plan Your Video Storage and Uploads Accurately
Guessing file sizes leads to full memory cards mid-shoot, storage drives that fill unexpectedly, and upload schedules that miss deadlines. The calculator above removes the guesswork. Enter your resolution, duration, codec, and audio quality to get precise estimates before you record, export, or schedule any upload.
For production planning, run the calculator with your typical project settings and multiply by your shooting ratio. Budget storage at 3x that estimate and verify your upload speed can handle the delivery timeline. Knowing your numbers before production starts prevents every common file management problem that derails video projects.
Free tool by: John Isaacson, Digital Marketing Strategist at JI Digital
Last Updated: January 2026
