Shadowing Practice: Will YouTube Ever Run Out Of Video IDs? - Learn English Speaking with Video

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Every YouTube video has a unique ID.
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It's up there in the URL, a string of 11 characters that uniquely identifies which video you want.
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Now, YouTube has millions and millions of videos.
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The last stats that they released said that they have 400 hours of video being uploaded every minute.
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So, are they ever going to run out of those IDs?
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Well, to find out, let's talk about counting systems.
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People count in base ten.
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Zero to nine.
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That'll be, hopefully, familiar to you.
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Computers count in base two, in binary.
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But that's difficult for humans to read.
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It gets too long to write really, really quickly.
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So, often computers will display it in base sixteen.
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Hexadecimal.
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You have zero to nine, and then A to F, and then you start adding to the next column.
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Humans can't understand that easily, but it's efficient if we have to type it in somewhere.
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And sixteen, two to the power of four, is also easy for computers to deal with.
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So how about base 64?
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That'd be a ridiculous counting system, right?
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Except 64 is another one of those easy numbers for computers.
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It is 2 to the power of 6.
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And humans can get to 64 very easily.
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0 to 9, then capital letters A to Z, then small letters A to Z, and two other characters.
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Most Base64 uses slash and plus, but they don't work so well in URLs, so YouTube uses hyphen and underscore.
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That YouTube URL, that unique ID, is really just a random number in Base64.
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They could have picked Base10 or Base16, but they didn't.
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They went with 64, because it will let you cram a huge number into a small space
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and still make it vaguely human-readable.
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Author and programmer Sam Hughes, by the way, pushed this to the limit and invented base 65,536,
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which includes basically every character from every language.
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It is ridiculous and unnecessary, but when has that ever stopped programmers?
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So, why didn't YouTube just start counting at one and work up?
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Well, first, they would have to synchronise their counting between all the servers handling the video uploads.
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Or they'd have to assign each server a block of numbers.
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Either way, there's a lot of tracking to do, a lot of making sure that it's never duplicated.
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Instead, they just generate a random number for each video, see if it's already taken, and if not, use it.
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And secondly, it is a really, really bad idea to just count one, two, three, or so on in URLs.
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Incremental counters, as they're called, can be a big security flaw.
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If you see video 283 up there, then you might wonder, what's video 284?
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Or video 282?
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It's easy to enumerate, as it's called, to run through the entire list.
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YouTube unlisted videos, the ones that don't appear publicly, but that you can send a link to people, those wouldn't work.
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And by the way, lots of badly designed sites do use incremental counters and it is a terrible idea.
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It might tell your competitors exactly how many customers you have, because they can just count them.
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It might let people download all your records easily, because they can just run through them.
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And in one site that someone in Florida emailed me about this week, it lets you look at other people's personal details.
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Don't use incremental counters.
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If you're building a website, use a random number.
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Which brings me to the question, just how big are the numbers that YouTube uses?
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Well, let's work it out.
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One character of base 64 lets you have 64 ID numbers.
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Two characters, that is 64 by 64, or 4096.
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Three characters, 64 times 64 times 64, or 64 to the power of 3, that is already more than a quarter of a million.
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And if we go to four, well, now we're above 16 million.
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If you used base 64, then you can assign an ID number to everyone who lives in London down there twice over,
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and you'll only need four characters.
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This gets big fast.
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We can keep on doing this, and by seven characters, we are already at four quadrillion.
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Now I assume that YouTube checks through a dictionary and doesn't allow any actual words to appear up there,
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particularly anything rude, but that is going to be a tiny minority of their URLs, so for our purposes, we can pretty much just ignore that.
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At YouTube's 11 characters, we are at 73 quintillion 786 quadrillion 976 trillion 294 billion 838 million 206 thousand and 464 videos.
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That is enough for every single human on planet Earth to upload a video every minute for around 18,000 years.
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YouTube planned ahead.
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Can they run out of URLs?
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Technically, yes.
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Practically, no. And if they did, they could just add one more character.
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Oh, one take!
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One take!
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Yes!

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What You'll Learn

This video helps you build two key speaking skills: explaining complex ideas clearly (like how counting systems work) and using conversational transitions ("Well," "So," "Instead"). You'll also practice understanding fast, natural speech about technical topics—great for real-world English listening and speaking practice.

Listen For These Sounds

Notice how the speaker links words: "it's up in the URL" becomes "it's upin the URL," and "a string of eleven" sounds like "a stringof eleven." Reductions like "they'd" (for "they would") and "that'll" (for "that will") are common—listen for how these shorten the flow. Also, focus on the stress in multi-syllabic words: "hexadecimal" (hex-a-DEC-i-mal) and "quadrillion" (quad-RIL-lion) have clear stressed syllables that shape the rhythm.

Say It Like a Native

To mirror the speaker's rhythm, practice the shadowing technique: pause the video, repeat short phrases, and match the speed and stress. For example, when saying "Base 64 is 2 to the power of 6," stress "Base 64" and "power" to emphasize key points. Use the speaker's curious tone—raise your voice slightly when asking questions ("Are they ever going to run out?") to sound natural. This helps improve English pronunciation and makes your speech feel more fluent. Try shadowing 30-second clips daily—you'll quickly notice how your rhythm and intonation match native speakers. Learning English with videos like this turns technical content into fun, practical speaking practice!

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

Shadowing technique: read the full step-by-step guide →