How Many Feet of Film Is on an 8mm Reel?

Most of our blog posts are centered on pretty easy to answer questions. We usually tell you things like “How wide is 8mm film?” The answer is easy: 8mm! Blog post over. Wrap it up. We’re done.

But this blog post won’t be so straightforward. Today, we’re turning the film the other direction and asking the same question: how long is the typical 8mm film reel? That’s a question that’s a little bit harder to answer, but we have the technology. But first, we’ll answer the question in a really annoying way. How big is a typical 8mm reel?

Well, it depends.

It turns out there’s no universal length for 8mm film, because it comes in different reel sizes. That also means different film lengths. Let’s take a look at those different reel sizes in this handy dandy chart.

Looking at the list, it’s pretty neat to see how long some of those film reels are! Even though the film is less than half an inch wide, the fact that it’s 50 feet long is quite the accomplishment! But how does that translate into viewing time? Let’s do some math.

First, we’ll figure out how many frames are each foot of film. A standard frame size for 8mm film is 4.8mm wide by 3.5mm tall. Doing a little metric to standard conversion leaves us with a frame height of .13 inches per frame. More math gets us to 7.69 frames per inch, which means 92.28 frames per foot.

Next, we need to figure out how fast the film plays. For most regular recordings, frame speed is around 18, and we use a scale called frames per second (FPS). That means each second of recording uses 18 separate pictures -- or frames.

Whew, let’s take a deep breath.

Alright, let’s keep going. If we know that FPS rate is 18, and a foot of film has around 92 frames in it, that means a foot of film contains around 5.1 seconds of footage. So what happens when we break out those film lengths from the earlier table and convert it to viewing time? Let’s see!

There you have it! If you’ve ever wondered how long 8mm film is and what that means for viewing time, now you know! We figured out that a foot of 8mm film contains around 92 frames and about 5 seconds of viewing time. Using some math, we figured out that you had to use a LOT of film to get a pretty short video -- about 2 giraffes worth of film would only give you around 4 minutes of run time.

That’s a lot of plastic!