Video Record Time & File Size Calculator

This Video Record Time & File Size Calculator helps you plan shoots and avoid full-card surprises. Enter your resolution, frame rate and codec, then set a bitrate that matches your camera profile. The calculator immediately estimates how many minutes fit on 32 GB, 64 GB, 128 GB and 256 GB cards and reports how many gigabytes one hour of video will consume. It also includes quick conversions between kbps, MB/s and GB/hour so you can translate marketing specs or NLE settings into real storage needs.

Bitrate controls your file size and recording time. Higher bitrates preserve more motion detail and fewer compression artifacts, but they chew through space faster. With modern long-GOP formats, H.265/HEVC typically needs around thirty percent less bitrate than H.264 for a similar quality target, while intraframe proxies (such as ProRes Proxy) use higher bitrates to stay easy to edit. Many cameras advertise “variable bitrate”: the real data rate fluctuates with scene complexity and noise. For planning, use the maximum or the manufacturer’s “typical” figure and keep a buffer.

A quick rule of thumb: at decimal units, 1 Mbps equals 0.125 MB/s. One hour at a given bitrate uses Mbps × 0.45 gigabytes. For example, 100 Mbps is about 45 GB/hour, so a 128 GB card fits roughly two hours and fifty minutes in ideal conditions. Cards are marketed in decimal GB, and cameras may reserve space for metadata; your usable time can be slightly lower in practice.

To choose a reasonable bitrate, consider your output and motion: talking-head videos at 1080p30 often look clean at 12–24 Mbps with H.264 or 9–18 Mbps with H.265. Fast action at 4K60 may need 100–200 Mbps for H.264, or around 70–140 Mbps for H.265. If you intend to color grade heavily or deliver to large screens, err higher. For editing performance on modest hardware, create proxy files (for example, ProRes Proxy 1080p30 at ~45–60 Mbps), which are bigger than long-GOP but scrub smoothly.

Storage planning tips:

• Leave headroom. Plan on filling only 80–90% of a card to avoid abrupt stops.
• Account for audio, timecode and container overhead, which add a small percentage.
• Prefer U3/V30 (or better) cards for sustained 4K recording; burst ratings alone are not enough.
• Match card speed class to codec. High-bitrate All-Intra or 4K120 often requires V60 or V90.
• Back up promptly. Keep at least two copies on separate devices when offloading footage.

Workflow ideas:

• Use consistent presets per camera profile so crews can estimate time at a glance.
• When mixing cameras, normalize to GB/hour to compare apples to apples across codecs.
• If you record long events, split by hour or scene to limit corruption risk on power loss.
• For web delivery, transcode masters to efficient streaming bitrates; keep the originals for archive.

Finally, test before the shoot. Record a few minutes of a representative scene, then check the actual file size on the card and compare with the calculator’s estimate. If your camera uses variable bitrate, expect variation across scenes; motion, foliage, water and high-ISO noise all push bitrates up. With the right presets and a sensible buffer, this calculator becomes a reliable planning companion for creators, editors, teachers and production managers who need fast answers on a phone in the field.