PlaylistTime / Guides / 2x speed

Watching YouTube at 2x Speed: Is It Bad for Learning, and How Much Time Does It Save?

Watching at 2x halves the time, and for short lectures studies found only a small drop in what people remembered at 2x, with a bigger drop above it. At 1.5x the cost was small and often not significant. The catch: most studies used short videos and young students, and one found older adults did worse at faster speeds.

Below is what the research actually measured, how much time each speed saves on real course playlists we measured on October 26, 2026, and how to set speeds on YouTube, including above 2x. For your own playlist, use our playlist length calculator: it shows the time at every speed at once.

Is watching videos at 2x speed bad?

Not for most short lectures: studies found small costs at 2x and larger ones beyond it. In the clearest experiment (Murphy and colleagues, 2022), students who watched a lecture at 2x scored 62% on an immediate test against 65% at normal speed, a difference that was not statistically significant. At 2.5x the score fell to 55%, which was.

A 2025 meta-analysis of 24 studies (Tharumalingam and colleagues) describes the cost as small, and often not significant, at 1.5x and slower; its title sums up the other side: increasing playback speed can impair test performance. So 2x is not harmful by itself, but it is near the point where understanding starts to slip.

Is watching lectures at 2x speed good?

It can be, if you use the saved time well. In the same 2022 study, watching a lecture twice at 2x right before a test a week later beat watching it once at 1x a week earlier (63% against 55%). Watching twice at 2x back to back gave no gain over once at 1x (63% against 64%). The time saved helps when you spend it on spacing out your review.

What the 2022 study tested

Proportion correct on 20-question tests, Experiment 1 of Murphy, Hoover, Agadzhanyan, Kuehn and Castel (2022), 231 UCLA undergraduates, two lectures of about 13 to 14 minutes. Only the 1x and 2.5x difference was significant.

Is 1.5x speed good for studying?

For most learners, yes: the measured cost at 1.5x is small. The 2025 meta-analysis found small, often non-significant costs at 1.5x and slower. A smaller 2022 study of 76 university students watching a 16-minute programming lesson (Mo and colleagues) got its best test scores at 1.25x (80.0) and 1.5x (76.4), against 72.4 at 1x and 66.5 at 2x, while the effort students reported rose with each step up. In that study, stronger students did best at 1.5x and weaker ones at 1.25x.

A field study on an online course (Lang and colleagues, 2020) randomly set some learners to 1.25x by default; they were more likely to get better grades, attempted more of the course and earned more certificates, while spending less time on video.

What the research says about faster playback

Six studies, in short, with their limits.

Murphy, Hoover, Agadzhanyan, Kuehn and Castel (2022)

Applied Cognitive Psychology. UCLA undergraduates tested online, lectures of about 13 to 14 minutes at 1x, 1.5x, 2x and 2.5x. Minimal costs up to 2x; performance declined beyond 2x. Limits: short videos, two topics, no pausing or notes, students only.

Murphy, Hoover and Castel (2023)

Memory. Younger adults (18 to 36) and older adults (61 to 94) at 0.75x, 1x and 2x. Younger adults showed no significant loss at faster speeds; older adults were generally impaired in two of three experiments, and the authors advise older adults against watching at faster speeds. Limits: immediate tests only, mixed results across experiments.

Tharumalingam, Roberts, Fawcett and Risko (2025)

Educational Psychology Review, meta-analysis of 110 effect sizes from 24 studies. The cost of faster playback was small, and often not significant, at 1.5x and slower. We read the abstract; the full paper is paywalled.

Huang, Du and Yang (2025)

Frontiers in Psychology, meta-analysis of 12 studies, mostly university students, speeds about 1.1x to 2.5x. Faster videos raised cognitive load and lowered retention and transfer scores. Limits: it compared "faster" with "normal" without separating speeds, and the authors flag possible publication bias.

Mo, Wang, Dai and Jin (2022)

Frontiers in Psychology. 76 students at one university, one 16-minute lesson, best scores at 1.25x and 1.5x. Limits: small sample, one subject, immediate test.

Lang, Chen, Mirzaei and Paepcke (2020)

Learning Analytics and Knowledge conference. Online course learners set to 1.0x or 1.25x; the 1.25x group did better on several measures. Limits: only 1.25x tested; we read the abstract.

How much time does 2x speed save?

Exactly half: a 2x video takes 50% of its length. 1.25x saves 20%, 1.5x saves a third (33%), 1.75x saves 43%, 2.5x saves 60% and 3x saves two thirds.

Formula: time saved = length - length / speed. Worked example: MIT's MIT 18.06 Linear Algebra, Spring 2005 playlist is 28h 00m. At 1.25x: 28h 00m / 1.25 = 22h 24m, saving 5h 36m. At 2x: 14h 00m, saving 14h 00m. At 3x: 9h 20m.

Time saved on real course playlists

How much time does 1.25 speed save?

20%: 12 minutes in every hour. A one-hour video takes 48 minutes at 1.25x. On the CS50P Python (Harvard) playlist (15h 54m) that is 3h 11m saved, which is why 1.25x is a common first step up.

How long is an hour at 1.5 speed?

40 minutes. Divide the length by the speed: 60 / 1.5 = 40.

For any other length, the watch time calculator does it for you.

Does watching a video at 2x speed cut it in half?

Yes, the watching time is cut exactly in half. A 20-minute video plays in 10 minutes. The video's own length does not change, and ads are not sped up, so real time with ads is a little longer than half.

How to watch YouTube at 2x speed

On a computer, open the video's Settings (the gear) and choose Speed. On a phone, tap the video, tap Settings, then Playback speed.

• Hold for 2x: on a phone, tap and hold anywhere on the video to play at 2x while you hold; lift your finger to stop.
• Keyboard: on a computer, Shift + . (the > key) speeds up and Shift + , (the < key) slows down.
• TV: on a video's watch page, select Settings, then Speed. YouTube notes speed may not be available on every TV.

How to watch YouTube faster than 2x

YouTube Premium members on mobile can choose speeds above 2x, up to 4x. YouTube's blog announced this in April 2025 ("4x playback speed is rolling out on YouTube Premium"), with steps such as 2.5x and 3x. YouTube also announced in October 2024 that speed can be fine-tuned in 0.05 steps. Its help pages do not list the exact custom range, so check the speed menu on your own device.

Without Premium, browser extensions can set higher speeds on a computer. Before installing one, check what it can read. Keep the research in mind: in the 2022 study, 2.5x was the first speed with a clear drop.

How many people watch YouTube at 2x speed?

There is no official YouTube figure. The closest number we found is from the 2022 study: 85% of a group of 123 UCLA students said they watch lectures faster than normal. That is one group of students, not all viewers.

Does 2x speed affect watch time?

For you as a viewer, it halves the time you spend. How faster playback counts in a creator's watch time statistics is not something YouTube's help pages explain, and we could not find an official answer, so we do not guess.

How to speed up without missing things

• Start at 1.25x and move up a step when the speaker sounds normal to you.
• Slow down for hard parts. Proofs, code and new vocabulary deserve 1x; recaps and examples can go faster.
• Spend the saved time on review. In the 2022 study, a second viewing right before the test made up for the speed.
• Older viewers: one study found faster speeds hurt older adults' memory of a lecture, so be cautious.
• Language lessons: listening is the skill, so normal speed or slower usually fits better.

Speed and daily minutes work together. For the MIT 18.06 Linear Algebra (Strang) playlist, 30 minutes a day at 1.5x finishes as fast as 45 minutes a day at 1x (38 days against 38):

PlaylistTime vs adding up times by hand vs YouTube

To see what a speed does to a whole playlist, you need its total first.

How accurate is a playlist length calculator?

Exact for every playable video; the speed maths is a plain division. The calculator leaves out private, deleted and blocked videos (and lists them), counts live streams only after they end, and does not include ads. Real watching time is a little longer if you pause or rewind.

Why we wrote this guide

“I was getting distracted on YouTube. This calculator helped me concentrate on my playlist, and it also helped me complete things on time.”

Nitin Raja, who builds PlaylistTime

Speed was one of the levers in that. A playlist that looks too long at 1x can fit the weeks you have at 1.5x, but only if you know the numbers and the trade-off. So this guide puts the research next to real lengths.

What we do differently: every speed at once from real YouTube durations, the time saved and the finish date for your minutes a day, with sources you can open. No account.

Sources

• Murphy, Hoover, Agadzhanyan, Kuehn and Castel (2022). Learning in double time: The effect of lecture video speed on immediate and delayed comprehension. Applied Cognitive Psychology 36(1), 69-82
• Murphy, Hoover and Castel (2023). The effect of video playback speed on learning and mind-wandering in younger and older adults. Memory 31(6), 802-817
• Tharumalingam, Roberts, Fawcett and Risko (2025). Increasing Video Lecture Playback Speed Can Impair Test Performance: a Meta-Analysis. Educational Psychology Review 37, 35. Abstract read; full text paywalled
• Huang, Du and Yang (2025). Facilitating or hindering learning: a meta-analysis of acceleration on video learning. Frontiers in Psychology 16, 1427609
• Mo, Wang, Dai and Jin (2022). Video Playback Speed Influence on Learning Effect From the Perspective of Personalized Adaptive Learning. Frontiers in Psychology 13, 839982
• Lang, Chen, Mirzaei and Paepcke (2020). Is faster better? A study of video playback speed. LAK 2020, 260-269. Abstract read
• YouTube Help: Speed up or slow down YouTube videos
• YouTube Help: Keyboard shortcuts
• YouTube Blog: YouTube at 20 (April 2025), 4x speed for Premium on mobile
• YouTube Blog: features and updates 2024, speed in 0.05 steps

Questions

Related tools

Built by Nitin Raja. Last updated October 26, 2026. About PlaylistTime