How do you add audio to Google Slides, and how do you cut the clip to fit?

What Google says Slides accepts

Three Google pages cover it, all read on 2026-10-25:

• Formats and the insert step: the Google Docs Editors Help article Insert or delete images & videos, in its section "Add audio file to a presentation", states: "You can add .mp3 and .wav files stored in your Drive to a presentation." The steps are: open the presentation, select the slide, click Insert, then Audio, choose the file, click Select. The page adds a tip that .wav files can be used from Chrome, Firefox, Safari and Microsoft Edge. It states no file size limit and no length limit, and it does not mention any other format.
• Sharing: the same article says Access checker automatically suggests permissions for new viewers of presentations that contain audio files, and that to make sure a presenter can play the audio you share the presentation with people as Editor, Commenter or Viewer and confirm the suggested changes. In practice the audio file in Drive has to be visible to whoever presents.
• Playback settings: the Google Workspace Updates post Enhance presentations in Slides with audio (2019-04-02) says that once the file is inserted, "Format options" in the toolbar lets you set playback options, volume and looping, and hide the audio icon or replace it with an image. It also says adding audio works on desktop only, while playback works on all platforms. We did not check whether the panel looks the same today.
• Getting the file into Drive: Google Drive Help, Upload files & folders to Google Drive: on drive.google.com click New, then File Upload, or drag the file into a Drive folder.

So the job on this site is to produce an .mp3 or .wav of the right length. The rest happens in Drive and Slides.

How we tested

• Music: three minutes of Mozart, Symphony No. 40, first movement, 1:00 to 4:00 (Musopen Symphony recording, public domain, from Wikimedia Commons), as a 16-bit 44.1 kHz stereo WAV.
• Narration stand-in: 60 s of synthetic speech from eSpeak NG (our own text), saved as AAC 64 kbps mono in an .m4a, the kind of file a phone recorder makes. It is not a real phone recording.
• Browser recording stand-in: a 3 min Opus .webm at 48 kHz, the format Chromium's recorder writes.
• Browser: Chromium 153 driven by Playwright 1.63, opening local copies of this site's audio cutter, M4A to MP3 converter and Video to MP3 converter. In the cutter we typed start 0 and ends of 10, 30, 60 and 180 s, saved WAV and MP3 at 128, 192, 256 and 320 kbps with the page's own Download button, and repeated the 30 s cut with the Fade in and Fade out sliders set.
• Reading back: FFmpeg 4.4.2 decoded every file; we counted samples, compared the WAV exports with the source sample by sample, and measured the loop seam as described below. The byte counts for lengths we did not export in the browser came from the same lamejs encoder build the pages use, run outside the browser; where both exist they match to the byte.

How big the file is

Per minute that is 0.96 MB at 128 kbps, 1.44 MB at 192, 1.92 MB at 256, 2.40 MB at 320 and 10.58 MB for WAV. A deck with a 30 s clip on each of ten slides is 7.2 MB of MP3 at 192 kbps or 53 MB of WAV. Mono does not make an MP3 smaller on these pages: the one minute of mono speech from the M4A converter was 960,470 bytes at 128 kbps, the same as a minute of stereo music. A mono WAV is half the stereo size, 5,292,044 bytes for one minute.

The page's size estimate before you download is close: it showed "≈ 703 KB" for the 30 s clip at 192 kbps and the file was 720,979 bytes, which is 704 KiB.

How long the clip really is

WAV is cut to the sample: the 30 s region came back as exactly 1,323,000 samples, and every sample of the 10 s, 30 s, 60 s and 180 s WAV exports was within 1 step of 16-bit rounding of the source. MP3 is a whole number of 1,152-sample frames plus a short run-in, so it is always a little longer than what you typed.

The extra 29 to 41 ms is quiet run-in and run-out, not music: at 192 kbps the 25 ms before the music peaked at −47 dBFS and the 16 ms after it at −28 dBFS, against −3 dBFS for the music itself. It does not matter for a clip that plays once on a slide. It matters a little for a loop, as the next section shows, and it means a clip timed to end exactly with an animation should be typed a few hundredths of a second short. The 25 ms offset is the MP3 encoder's delay; the files these pages write carry no header telling a player to skip it, which is why typed times land 25 ms early when such a file is cut again.

Making a clip that can loop

Google's 2019 post says the Format options panel can loop the audio. When a clip loops, its last sample is followed by its first, and if the music is in full swing at both ends that join is a step in the waveform, which is heard as a click. We played each 30 s export end-to-start and took the peak of a 2 kHz high-pass filter in the 20 ms around the join, the same measurement as in our guide on clicks at cuts. In a one-second stretch inside the music the same filter peaks at −31.6 dBFS, so anything much above that at the seam is the join itself.

The MP3 without a fade looks clean only because of the padding: the music starts 25 ms into the file and the file runs 16 ms past the end of the music, both nearly silent, so the loop point falls in that quiet and the music simply stops and restarts with a 41 ms hole. Whether that hole is heard depends on the music. A WAV with no fade clicks. The fix is the same for both: set Fade in to 1 s and Fade out to 2 s in the cutter before you download. The fades did not change the MP3's size (720,979 bytes either way) or its length.

We did not test the loop inside Slides, so we do not know whether Slides adds its own gap when it restarts the file.

Narration from a phone, or a browser recording

Phones usually record to .m4a, and a recording made in a browser is usually a .webm. Neither is on Google's list. Both pages below open the file and write an .mp3 you can upload to Drive.

For speech, 128 kbps is the lowest the M4A converter offers (its bitrate list for this mono file was 128, 160, 192, 256 and 320 kbps). The converter keeps the file mono and keeps any title tag; the cutter writes no tags, and is the page to use if you also want to trim the recording. If the .webm is a screen recording, the Video to MP3 converter is the direct route; our WebM guide covers the one thing to watch, which is the end time it fills in for you.

Step by step

1. Open the audio cutter and drop in the song or recording. MP3, WAV, M4A, AAC, OGG, Opus, FLAC and WebM open, and so does the sound of an MP4 or MOV.
2. Type the start and end times, or drag the handles on the waveform. For a clip that will loop, set Fade in 1 s and Fade out 2 s.
3. Choose MP3 and 192 kbps (WAV only for a sound effect of a few seconds), press Download.
4. Go to drive.google.com, click New, then File Upload, and pick the downloaded file (or drag it into a folder).
5. In Slides, select the slide, click Insert, then Audio, choose the file and click Select. Use Format options for autoplay, volume and loop. If you share the deck, accept the permission change Access checker proposes so the presenter can reach the file.

Questions

Can I put one audio file across several slides?

Google's help page and 2019 post describe inserting a file on a slide and the Format options panel for its playback; neither says how a clip behaves across slide changes, so we do not know, and we did not test it. If you cut one clip per slide instead, the cutter's "+ Add region" exports each region as its own file with the same format and fade settings.

Should I use 320 kbps?

It is 1.67 times the size of 192 kbps (2,401,175 against 1,440,705 bytes per minute) and adds the least loss if the file will be re-cut later. For a clip that is uploaded once and played through a laptop or room speaker, 192 kbps is the usual choice; the table above gives both.

Is there a file size limit in Slides?

Google's Slides help page states none for audio, and we did not find one on the Drive upload page either. The largest file the cutter downloaded in our test was the 3 min WAV at 31.8 MB, and the largest in the table is the 10 min MP3 at 14.4 MB, written by the same encoder outside the browser; we did not upload either to Drive or Slides.