Video Storage and Recording Time Calculator

Who this calculator is for

Four different people land on a page like this one, and they want different things from it.

• Somebody about to buy a card. You want to know whether 128 GB covers a holiday, a wedding or a match. Set the capacity, pick the format nearest to your camera, read the hours, then read the section below on why the real card runs out early. That section is what decides whether you buy one card or two.
• Somebody already shooting. There is a card in the camera and a day to get through. Use the second mode, how much space do I need, and put in the running time you expect to roll. You will know before lunch whether the day fits.
• Somebody delivering a file. A client or a platform has handed you a size limit. Use the third mode, or go straight to the bitrate calculator, which is built for the delivery side and adds the audio track to the sum.
• Somebody costing a job. You are turning a shooting schedule into a drive order. Work in gigabytes per hour, multiply by cameras and by days, then double the total, because a master with no backup is not a master.

The three questions, worked out on paper

None of this needs a tool. The tool is faster, but if you can do these three sums you can check any storage calculator on the internet, this one included.

How long can I record?

A 128 GB card, and a camera writing 53 Mbps, which is what GoPro's published times imply for a HERO13 Black at 4K 30 on the standard bit rate setting.

Turn the capacity into bits: 128,000,000,000 bytes times 8 is 1,024,000,000,000 bits. Divide by 53,000,000 bits per second and you get 19,320 seconds, which is 5 hours 22 minutes. That is the same figure GoPro prints in its own chart, which is worth noticing. The arithmetic and the manufacturer agree, so the method still holds when the manufacturer says nothing.

How much space do I need?

Ninety minutes of ProRes 422 HQ at UHD 30p. Apple publishes 884 Mbps for that exact frame size and frame rate.

884,000,000 bits per second times 5,400 seconds is 4,773,600,000,000 bits. Divide by 8 and you get 596,700,000,000 bytes, or 597 GB. Ninety minutes on one camera has eaten more than half a terabyte, before anybody has copied it anywhere.

What bitrate fits?

Two hours has to go on a 64 GB card. 64,000,000,000 bytes times 8 is 512,000,000,000 bits, divided by 7,200 seconds is 71,111,111 bits per second, so about 71 Mbps. Anything at or under that fits. In practice you want to be under it rather than on it, for the reasons two sections down.

How this calculator gets its numbers

All of it is one piece of arithmetic. A video file is a stream of bits, so the size of the file is the data rate multiplied by the duration, divided by eight to turn bits into bytes. Rearrange it and you get the recording time from a capacity, or the bitrate that fits a fixed slot. Three questions, one formula, which is why the three buttons at the top of the calculator all use the same engine.

The hard part is not the arithmetic. The hard part is the data rate, and that is where most storage calculators quietly make things up. A page that offers you a single number for 4K without asking which camera, which codec and which frame rate is guessing on your behalf. This one asks, and when it does not have a published figure it says so instead of inventing one.

Where the rates come from

• Apple ProRes. All 58 rows and 348 cells of the target data rate table from the Apple ProRes white paper, April 2022. Not retyped from a blog. Read out of the PDF and checked against Apple's own GB per hour column.
• Blackmagic RAW. Blackmagic publishes the compression ratio rather than a table of rates, so this site derives the rate from that ratio and shows the working. The result lands within two percent of the Blackmagic RAW data rate calculator on every setting tested.
• GoPro HERO13 Black. GoPro publishes recording time per mode on a 128 GB card in its GoPro HERO13 Black capacity chart and states that you can scale it to your card size. That is exactly what happens here.
• YouTube and Vimeo. Their published upload bitrate recommendations, kept as ranges where the publisher gives a range.

Three decisions this arithmetic settles

Numbers on their own are trivia. Here is what they are actually for.

A full day of consumer 4K on one card

Eight hours of coverage at 4K 30, using the 53 Mbps that GoPro's chart implies. That rate costs 23.85 GB per hour, so eight hours is 190.8 GB. A 256 GB card takes the day with room to spare. A 128 GB card does not, and finding that out at four in the afternoon is a different experience from finding it out the night before.

A Blackmagic RAW day at 6K

6K DCI at 24 fps, Blackmagic RAW 5:1, which works out at 1,147 Mbps, or 516 GB per hour. Roll ninety minutes across the day and you have written 774 GB. A one terabyte card holds it, once. The backup needs its own terabyte, and somebody has to be copying while the shoot is still running, because there is no second card that day.

An episode that has to reach a platform

A 42 minute cut exported at 40 Mbps of video plus a 384 kbps stereo track. That is 40.384 Mbps over 2,520 seconds, which is 12.72 GB. If the delivery limit is 10 GB, you now know that before you start the export rather than after, and the bitrate calculator will tell you what rate to use instead.

Five times this number is the wrong question

The arithmetic is always right. It is just sometimes answering something you did not ask.

Loop recording. Dash cams and security cameras overwrite the oldest footage rather than stopping. The card never fills. The question that matters is not how many hours it holds, it is how far back the loop reaches before your evidence is overwritten. That is the same sum read differently. Measure what your device writes, put it in the calculator, and the recording time it returns is the length of your history. At 24 Mbps, for instance, a 128 GB card keeps 11 hours 51 minutes and nothing older.

Continuous recording limits. Holding footage and recording it in one unbroken take are separate problems. Heat, battery, per clip limits and file system limits all stop cameras long before the media is full. A card that holds five hours may never see a take longer than thirty minutes.

The 4 GB file split. FAT32 cannot store a single file larger than 4 GB, so cameras writing to it chop the recording into 4 GB parts as they go. The SD Association puts SDHC cards, over 2 GB up to 32 GB, on FAT32, and SDXC, over 32 GB up to 2 TB, on exFAT, which has no practical file size limit. The footage is all there either way, but if you are recording a two hour stage show on a 32 GB card you will be joining clips in the edit.

The drive is not empty. Every result here assumes the whole capacity is free. A one terabyte working drive with an operating system, a Resolve database and last month's job on it is not a one terabyte drive. Read the free space, not the label.

Phones and cameras that publish nothing. Apple does not publish a megabytes per minute figure for iPhone video, and most mirrorless makers do not publish one either. Any site that shows you an official number for those is showing you a guess. Measure it in twenty seconds using the method below and you will have a figure that is true for your device instead of true for somebody's average.

Why the card fills up before the number says it should

Fourteen years of directing commercials in Sao Paulo taught me to distrust the theoretical figure, and there are four honest reasons the real card runs out early.

Variable bitrate. Most consumer and mirrorless cameras do not hold a constant rate. The number in the manual is a ceiling or an average. Shoot a static grey wall and the file is small. Shoot confetti, rain, or a handheld pan across foliage and the encoder spends everything it has. Two takes of the same length can differ by a third.

Formatting overhead. A freshly formatted card has slightly less room for your footage than the raw capacity, because the file system takes a slice for itself.

The camera stops early. A recorder needs space to close the file properly and write its index. It will not drive itself into the last byte and risk a corrupt clip. The last minute of a card is usually unreachable by design.

The files around the file. Sidecars, proxies, thumbnails, gyro data and audio all land on the same card. Blackmagic RAW writes a sidecar. Many cameras write a small proxy next to every clip. None of it is huge, and all of it is real.

This is why the calculator has a safety margin field that starts at zero. I will not pretend that a fixed percentage is a measured constant, because it is not. Ten percent is a habit that has kept me out of trouble on set. Type whatever your own experience says, and notice that the tool is asking you rather than deciding for you.

Find your own camera's bitrate in twenty seconds

If your camera is not in the menu, do not guess and do not let anyone else guess for you. Measure it, because it takes less time than searching for it.

1. Set the camera to the exact mode you plan to shoot, resolution and frame rate included.
2. Record roughly ten seconds of a normal scene, not a lens cap and not a blank wall, because a still frame flatters the encoder.
3. Look at the file size in megabytes and the duration in seconds.
4. Bitrate in Mbps is the size in megabytes, divided by the seconds, multiplied by eight.

A 240 MB clip that runs 10 seconds is 192 Mbps. Type that into the custom bitrate field and every answer on this page is now about your camera instead of somebody's average. Do it once per shooting mode and write it on a card in your kit bag.

Decimal gigabytes and binary gibibytes

A 128 GB card shows up as roughly 119 on a computer and nothing is missing. The manufacturer counts a gigabyte as one thousand million bytes. The operating system divides by 1024 three times and still writes GB on the screen, when the honest name for that unit is the gibibyte. This calculator uses decimal units by default because that is how cards are sold and how Apple and Blackmagic label their own figures. Both binary options are in the unit menu if you want to match what your computer shows.

What this calculator will not do

It will not show you a table of camera models with invented bitrates. It will not give you an Instagram recommended bitrate, because Instagram does not publish one, and inventing one to look complete would be lying to you in a table. It will not promise that your card holds exactly what the result says. It converts capacity into time using the best published figure available and tells you where that figure came from, and where nothing is published it hands you a way to measure it yourself.

Which of the three modes should I use?

This page solves one equation in three directions, so the mode you pick is really the question you are asking. How long can I record starts from a capacity and gives you time. How much space do I need starts from a running time and gives you bytes. What bitrate fits starts from both and gives you the highest rate that still lands inside the space. If you are buying a card use the first, if you are planning a shooting day use the second, and if somebody has handed you a hard size limit use the third or the bitrate calculator, which is built for delivery.

How many GB is one hour of video?

Multiply the bitrate in Mbps by 0.45 and you have gigabytes per hour. One hour at the YouTube 1080p upload target of 8 Mbps is 3.6 GB. One hour of consumer 4K at 53 Mbps is 23.9 GB. One hour of ProRes 422 HQ at UHD 30p is 398 GB. Resolution on its own tells you nothing, which is why every honest answer to this question begins with a bitrate.

How many MB is one minute of video?

Bitrate in Mbps times 7.5 gives megabytes per minute. So 8 Mbps is 60 MB a minute, 40 Mbps is 300 MB, 100 Mbps is 750 MB, and ProRes 422 HQ at UHD 30p is 6,630 MB, which is 6.6 GB for sixty seconds.

Why does this calculator ask which codec, instead of just asking for 4K?

Because resolution on its own does not determine file size and never has. Data rate does. Apple publishes ProRes 422 HQ at UHD 30p as 884 Mbps, and a consumer camera at the same 4K 30 writes around 53 Mbps. That is the same picture size and roughly seventeen times the storage. Any page that answers a 4K question with a single number has quietly chosen a codec on your behalf and not told you which one.

What does the safety margin field do?

It holds back a percentage of the capacity before the arithmetic runs, so the answer describes a card you can actually fill rather than a perfect one. It starts at zero on purpose. Formatting overhead, variable bitrate and the space a camera keeps back to close a file safely are all real, but no honest fixed percentage covers them for every card and every codec. Ten percent is a working habit rather than a measured constant. Type what your own experience says, and notice that the tool is asking you instead of deciding for you.

How many hours of 8K video can 1TB hold?

Apple publishes ProRes 422 at 8192 x 4320 30p as 2,514 Mbps, which gives 53 minutes on a terabyte. A delivery file is far lighter: at the bottom of the YouTube 8K upload range, 80 Mbps, a terabyte holds about 27 hours 46 minutes. Same resolution, thirty times the difference, decided entirely by the codec.

How many hours of video can an iPhone hold?

Apple does not publish a megabytes per minute figure for iPhone video, so this site will not print one. What you can do takes twenty seconds. Record ten seconds in the exact mode you use, divide the file size in megabytes by the seconds, multiply by eight, and type the result into the custom bitrate field. The answer is then about your phone rather than about somebody's average. Remember the phone is also carrying the operating system, apps and photos, so it is the free space that counts, not the number on the box.

How long does a dash cam or a security camera keep before it overwrites?

Both of those loop, which means the card never fills, it overwrites. The useful number is not how long it records, it is how far back the recording reaches before the oldest file is gone. It is the same arithmetic: measure the bitrate the device writes, put it in the calculator, and the recording time you get back is the length of your history.

How long is a 100MB video?

Divide the size in megabits by the bitrate. 100 MB is 800 megabits, so at 8 Mbps it runs 1 minute 40 seconds, at 40 Mbps it runs 20 seconds, and at the YouTube 480p target of 2.5 Mbps it runs 5 minutes 20 seconds. Turned around, that is the trick for measuring any camera: size in megabytes divided by seconds, times eight, is the bitrate in Mbps.

Does a flash drive hold the same video as an SD card of the same size?

For capacity, yes. A byte is a byte, so a 128 GB flash drive and a 128 GB card both hold 128,000,000,000 of them and both give the same recording time here. For recording, no. What separates them is sustained write speed, which is what decides whether a camera can keep up without dropping frames, and a USB flash drive is usually the weaker of the two at holding a rate. Capacity decides how long. Write speed decides whether it works at all.

Why does my card fill up before the calculator says it should?

Four reasons, and they all run against you. Most consumer cameras use variable bitrate, so a detailed scene writes more data than the average the manual quotes. Formatting takes a slice of the card. The camera stops before the last byte because it needs room to close the file safely. And sidecars, proxies and thumbnails land on the same card as the footage. Treat every estimate as an estimate and leave a margin.

Why does a 128GB card show as 119GB on my computer?

The card maker counts 1 GB as 1,000,000,000 bytes. Windows and most cameras divide the same bytes by 1,073,741,824, which is 1024 cubed, and still write GB on the screen. The honest name for that unit is the gibibyte. Nothing is missing and no space was lost. This calculator uses decimal units, the same way card makers, Apple and Blackmagic label their own figures, and offers GiB and TiB if you want the reading your computer shows.