Photography Calculators

Timelapse & video

Video File Size Calculator

Size is bitrate times time. 200 Mbps for 30 minutes is 45 GB of video payload before audio and wrappers. Cameras quote megabits per second; cards quote gigabytes. Divide bits by eight. Use this before a wedding so you do not fill the last card during vows.

Inputs

Units
Mbps

Camera or codec setting in megabits per second. 4K 10-bit is often 100–600 Mbps.

min

Recording time you need to fit, not the battery life.

Results

Size
45.00GB

Decimal gigabytes (1000 MB), the way cards are sold; not GiB.

Size
45,000MB

The same size in decimal megabytes.

The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.

Example products

Product links are Affiliate Links to Amazon websites. Using them does not cost you anything extra, and if you make a purchase we may receive a commission. Details: Terms of Service, point 5.

Calculation method

Megabits per second times 60 times minutes is total megabits. Divide by 8 to get megabytes. Divide by 1000 for gigabytes (decimal, the way cards are sold). 200 Mbps × 30 min × 60 / 8 = 45 000 MB = 45 GB. Audio and the container add a little; VBR can come in under the cap.

Exact formula

sizeMB = bitrateMbps × durationMinutes × 60 / 8. sizeGB = sizeMB / 1000. Limits: Audio, container overhead, variable bitrate and card formatting waste omitted; decimal GB (1000), not GiB.

Card speed

Capacity is not sustain rate. A V30 card is 30 MB/s = 240 Mbps theoretical; a 200 Mbps codec can still stutter if the camera writes bursts above that. Prefer V60/V90 or CFexpress for 4K high bitrate.

RAW video

ProRes RAW and BRAW can sit well above 1 Gbps. Type the actual data rate from the recorder manual, not the camera’s H.264 4K number.

Frequently asked questions

Mbps vs MB/s?

Cameras quote megabits (Mb) per second. Cards often show megabytes (MB) per second. 200 Mbps is 25 MB/s. Mixing them is how you buy a slow card.

ALL-I vs Long GOP?

ALL-I is a higher bitrate for the same look and a more predictable size. Long GOP can undershoot this estimate. Use the camera’s quoted Mbps.

Dual recording?

Proxy plus main is two bitrates. Add them, or run this twice and sum the GB.

Audio?

Small beside the video: 48 kHz 24-bit stereo PCM is about 2.3 Mbps, roughly 17 MB per minute, and it is not added here. Mirrored dual-slot recording writes everything twice, so it halves the usable capacity.

More in this topic

All tools in this topic