Pick a quality above and the whole page recalculates as you move the slider — nothing here waits for a “Calculate” button. Start with the resolution you actually watch at, since that one choice moves every other number on the page more than anything else does. The line under the pills shows the planning range behind that choice, not a single invented number.

The hours slider sets how much YouTube you watch in an average day, from a quick 15 minutes to a heavy 8-hour stretch. Fifteen minutes a day at 1080p is a different plan than two hours a day at the same quality, and the calculator treats them as genuinely different situations rather than scaling one generic number.

Below that, choose how your data actually gets billed. If you pay a flat rate per gigabyte — common on prepaid and eSIM plans — the first mode turns your viewing habit into a monthly cost in your own currency. Two hours a day at 720p on a $2-per-GB plan comes out to roughly 111 GB and about $222 a month, which is usually the moment people realize 720p isn’t the “safe” setting they assumed it was.

If instead you’re watching the clock on a fixed monthly allowance, switch to “I have a data plan with a deadline.” Enter what’s left in gigabytes and how many days remain in your billing cycle. With 10 GB left, 12 days to go, and 1.5 hours a day at 1080p, that habit runs out in about 2.2 days — well short of the cycle, and in this mode the calculator names the actual date it happens, not just a count.

Right above the gauge sits the one number most data calculators skip: the highest quality your remaining data can sustain without real risk. In the scenario above, that’s 480p, not 1080p — shown alongside the quality just above it (risky) and just below it (comfortable), so you can see how much margin you’re giving up either way. Clicking “Use this quality” switches the slider for you.

The bars underneath flip the question around: instead of “how much will I use,” they answer “how much can I still watch.” Given the same 10 GB, that’s roughly 3.3 hours at 1080p, 5.4 hours at 720p, or 18 hours at 480p — the same data budget stretched across very different amounts of actual viewing time.

“Download result as image” saves a card with your numbers — quality, pace, and either your monthly cost or your days remaining — so you can keep it or send it to whoever else is sharing the plan, without screenshotting the whole page.

None of the megabyte-per-hour figures behind this calculator come from an official YouTube table, because YouTube doesn’t publish one — quality shifts with your connection, and actual usage shifts with codec, frame rate, and the video itself. The ranges come from independent measurements (Android Authority and similar testing); the calculator uses the middle of that range for its numbers and shows the full range next to the quality selector, rather than pretending to a precision the data doesn’t have.