Video File Size Calculator
Enter your resolution, frame rate, codec and recording time — get the exact storage you'll need, the data rate, and the right SD card speed class, in real time.
Your shoot
How video file size is calculated
Every video file boils down to one simple relationship between its bitrate and its length:
The bitrate is the number of megabits the camera records each second. It rises with resolution (more pixels), frame rate (more frames per second) and the codec you choose — lightly-compressed formats like ProRes or RAW use far higher bitrates than delivery codecs like H.264 or H.265. Multiply that bitrate by the recording time, divide by 8 to turn bits into bytes, and you have the file size. We also surface the data rate (MB/s), because that's what actually decides which memory card is fast enough to keep up.
Example: file size of 1 hour in 4K
Say you're shooting 4K UHD at 30 fps in H.265 for 60 minutes:
- H.265 at 1080p30 is 25 Mbps; ×4 for 4K resolution = 100 Mbps at 30 fps.
- 100 Mbps × 3,600 s ÷ 8 = 45,000 MB = 45 GB for the hour (45.1 GB with stereo audio).
- Data rate = 100 ÷ 8 = 12.5 MB/s → a V30 card handles it; a 64 GB card is enough.
Switch the codec to ProRes 422 HQ (880 Mbps) and the same hour jumps to about 396 GB at 110 MB/s — beyond SD-card territory: you'd need CFexpress Type A or an external SSD.
Quick reference table
Bitrate and size per hour at 30 fps, no audio. At 60 fps, H.264 and H.265 take about 1.5× more:
| Resolution | H.264 | Per hour | H.265 | Per hour |
|---|---|---|---|---|
| 720p | 22 Mbps | 10 GB | 11 Mbps | 5 GB |
| 1080p | 50 Mbps | 22.5 GB | 25 Mbps | 11.3 GB |
| 1440p | 89 Mbps | 40 GB | 44 Mbps | 20 GB |
| 4K UHD | 200 Mbps | 90 GB | 100 Mbps | 45 GB |
| 6K | 512 Mbps | 230 GB | 256 Mbps | 115 GB |
| 8K UHD | 800 Mbps | 360 GB | 400 Mbps | 180 GB |
VP9 lands close to H.265 and AV1 saves about 30% more (at 4K30: ≈ 49 and 32 GB/h). Editing codecs blow it up: at 4K30, ProRes 422 ≈ 265 GB/h, Blackmagic RAW 5:1 ≈ 268 GB/h, and ProRes 422 HQ and DNxHR HQX ≈ 396 GB/h. Use the calculator above for your exact combination.
Methodology & sources
Every result is computed in your browser with the formula shown above — nothing is sent to a server. The numeric model is based on this data and these references:
- SD Association — Video Speed Classes (V30/V60/V90)
- CompactFlash Association — CFexpress specification
- Apple ProRes — White Paper (data rates per variant)
- Typical recording bitrates per codec: ProRes per Apple; Blackmagic RAW 5:1 = 12-bit raw ÷ 5; H.265 ≈ half of H.264 at equal quality.
- Card capacities in decimal GB, as they are sold (1 GB = 10⁹ bytes), with a 2% safety margin.
Formula reviewed and verified against real-world cases.