HEVC vs H.264: how much space you really save

September 26, 2026 • VideoRecompress Studio Team

At the same quality setting, H.265 (HEVC) files were a median 33 % smaller than H.264 in our 11 measured pairs, and smaller in 10 of them. Converting H.264 files we already had to H.265 on the GPU saved 31 to 65 %. H.264 still plays on more devices; AV1 saves more again but takes far longer to encode.

−33 %median H.265 saving over H.264 at the same quality setting
10 / 11pairs where the H.265 file came out smaller
−65 %an 83-second iPad video, H.264 to H.265 on the GPU (86.1 MB to 30.0 MB)

Measured on 26 September 2026 with VideoRecompress 2026.2.18 on a Ryzen 9 3900X with an RTX 3080. GPU = NVIDIA NVENC; CPU = x264, x265 and SVT-AV1. H.264 and H.265 at quality 23 (the default); AV1 at the settings of the Maximum Savings preset (CRF 35). VMAF compares each file with its source: 100 = identical.

Same master, three codecs

Three 12-second clips were first saved almost lossless (x264 CRF 12), then encoded by VideoRecompress at its default quality setting (23) with each codec. Bars show the size against that master.

Phone video, 720p portrait

Master · 28.9 MB

H.264CPU8.2 MB · −72 % · VMAF 94.6
H.265CPU5.2 MB · −82 % · VMAF 93.5
H.264GPU5.7 MB · −80 % · VMAF 89.0
H.265GPU4.5 MB · −84 % · VMAF 90.2
AV1CPU3.0 MB · −90 % · VMAF 91.6

Film scene, 1080p

Master · 15.5 MB

H.264CPU4.1 MB · −74 % · VMAF 97.1
H.265CPU2.8 MB · −82 % · VMAF 97.5
H.264GPU5.4 MB · −65 % · VMAF 97.5
H.265GPU3.6 MB · −77 % · VMAF 97.5
AV1CPU1.9 MB · −88 % · VMAF 96.4

Fast sport, 640x480

Master · 13.8 MB

H.264CPU5.5 MB · −61 % · VMAF 99.7
H.265CPU6.1 MB · −56 % · VMAF 99.5
H.264GPU2.7 MB · −80 % · VMAF 82.6
H.265GPU2.3 MB · −84 % · VMAF 78.4
AV1CPU5.8 MB · −58 % · VMAF 98.4
H.264H.265 (HEVC)AV1

The exception is the low-resolution sports clip: at 640x480, H.265 on the CPU wrote 11 % more than H.264 (both near VMAF 99.5), and both GPU encoders lost quality (VMAF 78 to 83). Small frames leave H.265 little to gain.

Converting H.264 files you already have

Three real H.264 files, converted at the default setting. This is what happens to a library you already own.

iPad video, 720p, 83 seconds

Original, H.264 · 86.1 MB

H.264CPU52.0 MB · −40 % · VMAF 90.7
H.265CPU31.5 MB · −63 % · VMAF 89.8
H.264GPU37.7 MB · −56 % · VMAF 86.0
H.265GPU30.0 MB · −65 % · VMAF 87.6
AV1CPU17.4 MB · −80 % · VMAF 87.4

GoPro clip, 1080p, 20 seconds

Original, H.264 · 31.3 MB

H.264CPU31.3 MB · would grow: original kept
H.265CPU31.3 MB · would grow: original kept
H.264GPU26.5 MB · −15 % · VMAF 94.0
H.265GPU21.6 MB · −31 % · VMAF 92.3
AV1CPU30.7 MB · −2 % · VMAF 99.7

Lecture recording, 1440p, 28 seconds

Original, H.264 · 20.7 MB

H.264CPU15.2 MB · −26 % · VMAF 96.5
H.265CPU9.2 MB · −55 % · VMAF 96.3
H.264GPU19.9 MB · −4 % · VMAF 96.5
H.265GPU13.2 MB · −36 % · VMAF 96.7
AV1CPU6.1 MB · −70 % · VMAF 95.9

Grainy footage like the GoPro clip gains least. The CPU encoders would have made it bigger than the 31.3 MB original, so VideoRecompress kept the original.

GPU or CPU

17×faster on the GPU: the iPad video took 4.6 s instead of 77.9 s (H.265)
89.8 / 87.6VMAF on the CPU vs the GPU for that video, at a similar size (31.5 vs 30.0 MB)
−30 %smaller on the CPU for the lecture at the same VMAF (9.2 vs 13.2 MB), but 9× slower

For H.265, the GPU (NVIDIA NVENC on an RTX 3080) was 8 to 17 times faster than the CPU (x265 on a 12-core Ryzen 9 3900X). The CPU packs more quality into each megabyte. For a large library, the GPU is the practical choice; for an archive you encode once, the CPU is worth the wait.

Which devices play HEVC

H.264H.265 (HEVC)AV1
Windows 10 and 11 Yes With the HEVC Video Extensions (Microsoft Store) With the free AV1 Video Extension
iPhone and iPad Yes Yes, since iOS 11 iPhone 15 Pro and newer
Android phones Yes Most phones Newer phones
Smart TVs Yes Most 4K TVs Newer models
Web browsers Yes Depends on the browser and the GPU Chrome, Edge and Firefox
Plex Plays directly Plays directly where the app supports it; otherwise the server converts it Plays directly where the app supports it; otherwise the server converts it

Play a converted file on your own devices before you delete any originals. If one of them needs H.264, VideoRecompress converts HEVC back to H.264 as well.

AV1 vs H.265

−42 %smaller than H.265 at the same VMAF (iPad video: 17.4 vs 30.0 MB)
−33 %smaller than H.265 on the CPU for the lecture (6.1 vs 9.2 MB), VMAF 95.9 vs 96.3
15×longer to encode than H.265 on the GPU (69 s vs 4.6 s): the RTX 3080 has no AV1 encoder, so AV1 ran on the CPU

AV1 is the smallest option when you have the time or a GPU with an AV1 encoder (NVIDIA RTX 40 series and newer, Intel Arc, AMD Radeon RX 7000). On the grainy GoPro clip it saved only 2 %. Choose H.265 for files that must play on today's TVs and phones. Read the full H.265 vs AV1 comparison.

When H.265 would make a file bigger

  1. Drop a folderSubfolders included. Videos already in H.265 are not re-encoded.
  2. Encode on the GPUNVIDIA, Intel or AMD, picked automatically. No GPU? The CPU does it.
  3. Check the sizeEach new file is compared with its original.
  4. Keep the smaller fileIf the new file is bigger, the original is kept as it was.

From the tests above: on the grainy GoPro clip, both CPU encoders would have written a file bigger than the original, so VideoRecompress kept the original and moved on.

Related articles

H.265 vs AV1: the full comparison How much disk space recompressing saves Convert HEVC to H.264 GoPro LRV and THM files

Questions

Is HEVC better than H.264?

For file size, yes. At the same quality setting, H.265 files were a median 33 % smaller than H.264 in our tests. H.264 still plays on more devices, including older TVs and some browsers.

How much smaller is H.265 than H.264?

In our 11 measured pairs, 17 to 39 % smaller, median 33 %. One low-resolution sports clip came out 11 % bigger on the CPU encoder, so the saving depends on the video.

Does converting H.264 to H.265 lose quality?

Every re-encode loses a little detail. The H.265 files in this test scored VMAF 78 to 99.5 against their sources (100 = identical); the lowest was a low-resolution sports clip on the GPU. Keep the originals of important footage until you have watched the results.

Is AV1 better than H.265?

For size, yes: at the Maximum Savings settings, AV1 was 42 % smaller than H.265 on the iPad video at the same VMAF. It took 15 times longer to encode on our PC and plays on fewer devices.

Can I convert HEVC back to H.264?

Yes. VideoRecompress converts in both directions: choose H.264 as the output codec, for a whole folder at once.

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