Video Duration Calculator
Determine exactly how many minutes or hours of continuous video you can capture based on available storage capacity, video bitrate, and audio track reservation.
Last Updated: November 4, 2026
Media Card Storage Capacity Reference Chart
Estimated maximum recording times across common flash memory cards and external SSDs:
| Drive / Card Size | 1080p30 (10 Mbps) | 1080p60 (25 Mbps) | 4K30 H.264 (60 Mbps) | 4K60 HEVC (100 Mbps) | 4K ProRes 422 (500 Mbps) |
|---|---|---|---|---|---|
| 32 GB SD Card | ~7.1 Hours | ~2.8 Hours | ~1.1 Hours | ~42 Minutes | ~8.5 Minutes |
| 64 GB SD Card | ~14.2 Hours | ~5.6 Hours | ~2.3 Hours | ~1.4 Hours | ~17 Minutes |
| 128 GB SD Card | ~28.4 Hours | ~11.3 Hours | ~4.7 Hours | ~2.8 Hours | ~34 Minutes |
| 256 GB Card / SSD | ~56.8 Hours | ~22.7 Hours | ~9.4 Hours | ~5.6 Hours | ~1.1 Hours |
| 512 GB Card / SSD | ~113.7 Hours | ~45.5 Hours | ~18.9 Hours | ~11.3 Hours | ~2.2 Hours |
| 1 TB (1,000 GB) SSD | ~227.5 Hours | ~91.0 Hours | ~37.9 Hours | ~22.7 Hours | ~4.5 Hours |
The 85% Flash Rule
Never fill solid-state flash media or SD cards beyond 85% of total capacity. When flash drives exceed 85% utilization, the controller exhausts free NAND blocks, write speeds drop drastically, and cameras can abort recording mid-take due to buffer overrun errors.
SD Card Speed Class Requirements
Verify that your card's sustained write speed matches your video bitrate. Standard V30 cards guarantee 30 MB/s (240 Mbps) sustained writes, sufficient for all 4K H.264/HEVC recording. For 4K ProRes (500+ Mbps), a V90 card (90 MB/s) or dedicated external USB-C NVMe SSD is mandatory.
Frequently Asked Questions: Recording Duration
How many hours of 1080p video can a 128GB SD card hold?
At a standard 1080p60 bitrate of 25 Mbps (typical for mirrorless cameras like Sony Alpha or Canon R), a 128GB SD card holds approximately 11.3 hours of continuous video. If recording at YouTube-recommended 12 Mbps, you can record approximately 23.7 hours.
Why do cameras stop recording before the SD card is completely 100% full?
Professional camera operating systems reserve a buffer (typically 1GB to 2GB) to write final MP4/MOV container index moov atoms, finalize file tables, and prevent filesystem corruption from unexpected power loss. Furthermore, flash memory controllers need unallocated blocks to perform wear leveling and garbage collection.
How much 4K ProRes 422 video fits on a 1TB SSD?
ProRes 422 at 4K UHD 24 fps records at approximately 503 Mbps (~63 MB/second). A 1TB drive (1,000,000 MB decimal) provides approximately 4.4 hours of 4K ProRes 422 recording time. At 60 fps ProRes, bitrate rises to ~1,250 Mbps (~156 MB/s), reducing recording time to ~1.7 hours.
How does Variable Bitrate (VBR) impact duration calculations?
Duration calculations assume a constant average bitrate. If shooting scenes with high motion, confetti, or foliage, VBR encoders increase momentary bitrates by 50% to 100%, shortening expected recording time. For mission-critical shoots, always plan with a 15% to 20% storage safety buffer.