For most short-form video, OpusClip is the best AI sound effect tool when the job is placing sound effects automatically on a video that is already being clipped and captioned: its Auto SFX feature detects key moments and puts effects on the timeline, and every effect stays editable. ElevenLabs is the pick for generating a bespoke sound from a text prompt, Mirelo for generating sound for a finished edit, and Epidemic Sound, Artlist, Pixabay and Freesound for library sounds. We ranked 8 tools by the job each does best, then by price, free-tier limits and how clearly each vendor documents what it does.

Updated October 29, 2026. We make OpusClip, so we rank it first for the job named above, and we say plainly where a dedicated sound generator or a sound library is the better fit. Every fact about every tool below comes from that tool's own pricing page, docs or help center, read on October 29, 2026.

At a glance

• OpusClip: best for automatically placing sound effects on a video already being clipped and captioned; Auto SFX is on the Pro plan ($29 a month, or $14.50 a month billed annually) and Business; the Free and Starter plans do not include it.
• ElevenLabs: best for generating a bespoke sound effect from a text prompt; Free plan yes (10,000 credits a month, non-commercial use only); paid plans from $6 a month listed (a first-month promotion was also showing).
• Mirelo: best for generating sound effects and ambience from a finished video; Free plan yes (5,000 credits a month, watermark on exports); Creator at 20 euros a month.
• Epidemic Sound: best for a large licensed sound effects catalog with channel clearance for creators; free trial yes, no free tier; see the pricing page for prices.
• Artlist: best for a stock SFX catalog bundled with music and footage; a dedicated Sound Effects Pro plan exists; see the pricing page for prices.
• Descript: best for editing video by transcript with a built-in stock library that includes sound effects; Free $0; Hobbyist from $16 a month billed annually.
• Pixabay: best for free, no-attribution library sounds; free, 130,000+ sound effects listed.
• Freesound: best for free community-uploaded recordings when attribution is manageable; free, with Creative Commons licenses that differ per sound.

1. OpusClip: Best for automatically placing sound effects on a video you are already clipping and captioning

OpusClip's Auto SFX watches a video, detects key moments and places sound effects on the timeline automatically. Per the OpusClip help center, it takes under 2 minutes for a 60-second clip, and it detects transitions, impacts, UI moments, ambient sounds and more, matched to the video's content and tone. It can be opened from the Auto SFX tile in the homepage Quick Start, or from the editor by opening a clip and choosing Audio in the right sidebar, then the Auto SFX tab and Auto generate sounds. Because this sits inside the same project where OpusClip finds clips from a long video, adds animated captions and reframes to 9:16, 1:1, 4:5 or 16:9, the sound pass is one more step in the workflow rather than a separate app. See OpusClip's AI video editor for the wider editor.

The placed effects are not locked in. Each one appears as a colored block on the timeline, and clicking a block lets the volume and duration be adjusted, or the prompt edited so that one sound can be regenerated. Per the help center, each block lives on a separate track, so a block can be deleted or regenerated without touching the rest, and the original footage and audio are not changed. For a specific sound, Generate by prompt takes a short description (the help center's examples are "funny sound effect" and "deep cinematic boom") and a duration, and returns three versions to pick from. The standalone page for that is OpusClip's AI sound effect generator.

Per the help center and the tool page, Auto SFX is available on the Pro and Business plans, and the plan table marks Free and Starter as not included. On opus.pro/pricing, Pro is $29 a month or $14.50 a month billed annually ($174), with 300 credits a month that roll over for 2 months. Free is $0 with 60 credits a month, a watermark and no editing; Starter is $15 a month with 150 credits; Business is custom. The Auto SFX help article does not say whether generating effects uses credits, so check that in the app before relying on it.

The honest limitations: the generated sounds live inside OpusClip, and the tool page says they are exported with the finished video, so a sound cannot be downloaded on its own to reuse elsewhere. The help center does not describe a way to choose which moments get effects before generation, only to edit or delete them afterward. OpusClip also describes the feature around video it is working on, so it is not a general sound library. Choose it if the job is adding sound design to short clips that are already being clipped, captioned and posted from one place, on the Pro plan. Skip it if the need is a specific sound to download and reuse across tools, or a free tier.

2. ElevenLabs: Best for generating a bespoke sound effect from a text prompt

ElevenLabs turns a text description into a sound effect, and for bespoke sounds a dedicated generator is the better tool than anything bundled into an editor. Its sound effects page says a generation returns four samples within seconds, and its docs list a duration setting from 0.1 to 30 seconds, a looping option for ambient sounds and a prompt-influence control. The docs' prompt guide covers simple effects ("glass shattering on concrete"), sequences ("footsteps on gravel, then a metallic door opens") and musical elements. Its page says sounds can be downloaded in MP3 format.

ElevenLabs' pricing page lists a Free plan at $0 with 10,000 credits a month and Sound Effects among the included products. Paid plans listed there are Starter at $6 a month (with a first-month promotion showing at $1 while the page was read), Creator at $22 a month ($11 for the first month), Pro at $99 and larger plans above that. The pricing FAQ puts Sound Effects at roughly 200 credits per generation, and the docs list 40 credits per second when a duration is specified. At that rate, our arithmetic puts the Free plan at about 50 generations a month and Starter at about 150.

The important limit for video makers is licensing: ElevenLabs' sound effects page says paid accounts can use the sounds in commercial projects, including YouTube videos, social media and advertising, and that free users may only use the services for non-commercial purposes. The other limit is workflow. ElevenLabs generates audio, so a sound still has to be dropped onto the right frame in whatever editor holds the video. Choose it if the sound is specific (a branded sting, a monster, a particular room tone) and the edit happens elsewhere. Skip it if the goal is to have effects placed on a video automatically.

3. Mirelo: Best for generating sound effects and ambience from a finished video

Mirelo generates sound from the video itself. Its site describes uploading an edit of up to 10 minutes (dialogue included) and getting new sound effects built around the speech, with baked-in music removed, and then optionally adding generated music. That makes it the closest rival to OpusClip's Auto SFX in spirit, since both look at the picture rather than waiting for a prompt, but Mirelo works on an uploaded video rather than inside a clipping and captioning workflow.

Mirelo's pricing page lists a Free plan at 0 euros with 5,000 credits a month, 3 projects and a watermark on exports; Creator at 20 euros a month with 24,000 credits and 20 projects; Studio at 99 euros a month with 120,000 credits; and Scale at 299 euros a month. Its capacity table shows roughly 8 minutes of SFX 2.0 output a month on Free and about 40 minutes on Creator, and it notes that SFX 2.0 is at a discounted rate until December 12, 2026. Mirelo's site also lists plugins for Adobe Premiere Pro and DaVinci Resolve, an MCP server for use in Claude, ChatGPT and Cursor, and an API.

The limitations are the watermark and project cap on Free, and the fact that the sound is generated on a finished edit, so captions, clips and posting happen elsewhere. We did not find a licensing summary on the pages we read, so commercial-use terms should be checked on Mirelo's own site before publishing. Choose it if a finished edit needs layered foley and ambience generated from the picture, especially inside Premiere Pro or DaVinci Resolve. Skip it if the video is still being cut into clips and captioned.

4. Epidemic Sound: Best for a large licensed sound effects catalog with channel clearance

Epidemic Sound is a subscription library rather than an AI generator. Its sound effects page lists a catalog of over 250,000 sound effects and variations across more than 700 categories, in WAV or MP3, with unlimited downloads on every plan. Its FAQ says Adobe Premiere Pro and DaVinci Resolve Studio plugins are included on every plan, and that sounds can be used on YouTube, TikTok, Instagram, Facebook, Twitch and podcast platforms once the channels are connected to the account (a step the page calls safelisting, which it says keeps copyright claims off the content).

Licensing is the real selling point, and it has tiers. Per Epidemic Sound's FAQ, the Creator plan covers non-commercial publishing, while commercial work, client projects and digital ads need Pro or above, and TV ads need Pro Plus or Enterprise. The pricing page offers a free trial but says there is no separate free tier; its prices were not readable in the page source we fetched, so see the pricing page for numbers. Its own FAQ is also candid that no sound effect is copyright free: a subscription gives a license cleared for the platforms the plan covers.

The limitation is that sounds are found and placed by hand (search, preview, download or use the plugin), and the license runs on an active subscription, since the FAQ says publishing new content after the trial needs one. Choose it if a team publishes often, needs clear commercial licensing and wants a deep catalog. Skip it if the goal is automatic placement or a custom sound.

5. Artlist: Best for a stock SFX catalog bundled with music and footage

Artlist sells a catalog of music, sound effects, footage, templates and LUTs, alongside AI tools for video, image, voiceover and music. Its sound effects page offers filters such as ambience, foley and transitions, and its pricing FAQ points to a Music and SFX plan, the Max plan, and a dedicated Sound Effects Pro plan for people who only need sound effects. Its FAQ says AI plans work on monthly credits, with some models offering unlimited generation.

Artlist's pricing page did not show a readable price for the Sound Effects Pro plan in the page source we fetched, so see the pricing page for numbers. We also did not find a sound-effect-specific generation feature on the pages we read: the AI tools it lists are video, image, voiceover and music. That makes Artlist a catalog choice for sound effects, not a generator or an automatic placer.

The limitation is choice overload and plan complexity: the pricing FAQ describes several plan families, and which one covers sound effects depends on the bundle. Choose it if one subscription for sound effects, music and footage appeals more than a standalone tool. Skip it if a free option or automatic placement is the priority.

6. Descript: Best for editing video by transcript with a built-in stock library

Descript edits video by editing its transcript, and its pricing page lists access to built-in libraries of royalty-free videos, images, GIFs, music and sound effects for use in projects. It is not an AI sound effect generator or an automatic placer, so the fit is a spoken-word edit where a few stock effects get dropped in by hand. Its plans also list Underlord (its AI co-editor), Studio Sound and Remove Filler Words.

Descript's pricing page lists Free at $0 (60 media minutes a month), Hobbyist at $16 a month billed annually or $24 monthly (10 media hours, watermark-free 1080p export), Creator at $24 or $35 and Business at $50 or $65. The page notes that stock library access has a limit on the number of search results usable per search, and the Creator column lists unlimited access to the stock media library. The pricing page did not make clear which lower plans get which search limit, so check it.

The limitation is that the sound effects part of Descript is a library, not a generator, and the page does not describe automatic placement. Choose it if the edit is transcript-first and a library of stock sounds is enough. Skip it if the video is mostly short clips, or the sound needs to be generated.

7. Pixabay: Best for free, no-attribution library sounds

Pixabay's sound effects page lists over 130,000 free sound effects shared by its community, with popular searches such as whoosh, riser, pop, notification and glitch. Its license summary says content can be used for free, without attribution (though credit is appreciated), and can be modified or adapted into new works.

The license summary also lists prohibited uses, including selling or distributing content on a standalone basis, using content with recognizable trademarks, logos or brands for commercial purposes in relation to goods and services, and using it in a misleading way. It adds that only the full Content License is legally binding. The limitations are practical: quality varies because the catalog is community-shared, there is no automatic placement, and a sound used by many videos is not distinctive. Choose it if the budget is zero and a common whoosh or pop will do. Skip it if the sound needs to be unique, or the licensing needs a paid vendor's clearance.

8. Freesound: Best for free community-uploaded recordings when attribution is manageable

Freesound is a collaborative database of audio snippets, samples and recordings released under Creative Commons licenses. Its FAQ says each sound carries one of three licenses: CC0 (the sound can be used with few conditions, but the user cannot claim authorship), Attribution (the original creator must be credited), and Attribution Noncommercial (credit required, and no earning money from the work). The FAQ also explains a legacy license, Sampling+, that is being removed.

The catch for video makers is bookkeeping. Credit lines have to be written for sounds that require attribution, and noncommercial sounds cannot be used in monetized work. Freesound's own FAQ also warns that a sound used in a YouTube video can get a copyright claim through Content ID scanning, because other users may have used the same sound unchanged in songs, and says such claims can often be disputed. Freesound is free, but it is a library of user uploads with no automatic placement. Choose it if an unusual field recording is needed and the license of each sound will be checked. Skip it if a team needs a single license that covers everything, or speed matters more than cost.

How we compared these tools

We compared each tool on the job it does best, price and free-tier limits, licensing for commercial use, how sounds get onto the video (automatic placement, generation from a prompt, or manual placement from a library), and the main limitation. Every fact comes from that vendor's own pricing page, help center, docs or site, read on October 29, 2026. Where a pricing page did not show readable amounts (Epidemic Sound and Artlist), we point to the pricing page instead of guessing. Adobe's Firefly pages blocked plain page requests, and CapCut's pricing page did not mention sound effects, so we left both out rather than describe them from memory.

We did not run hands-on tests of the competing tools, and the OpusClip description comes from its help center and tool page rather than from a controlled listening test. This is a comparison of published pricing and documented features, which is why the title says Compared and not Tested. Prices change often and some pages show promotions, so check the vendor's page before buying.

How to choose

• Start from the job. Effects placed automatically on a video being clipped and captioned point to OpusClip. A single bespoke sound points to ElevenLabs. Sound generated from a finished edit points to Mirelo. A browsable stock library points to Epidemic Sound, Artlist, Pixabay or Freesound.
• Start from the license. Free tiers and free libraries come with conditions: ElevenLabs Free is non-commercial only, Freesound sounds need attribution or exclude commercial use depending on the license, and Epidemic Sound's Creator plan covers non-commercial publishing only.
• Start from the budget. Pixabay and Freesound cost nothing, ElevenLabs and Mirelo have free plans with limits, and OpusClip's Auto SFX needs the Pro plan.
• Check the workflow. A generator or library is one more app to download from and import into. A tool inside the editor saves that step but ties the sound to that editor. For the rest of the short-form pipeline, see OpusClip's add sound effects to video tool and its transition sound effects page.
• Mind the age of advice. An older OpusClip post on talking avatars and AI sound effects covers tools from an earlier wave of AI video, so treat its tool details as dated.

Red flags to watch for

• Free tiers that block commercial use. ElevenLabs says free users may only use its services for non-commercial purposes. Posting monetized videos with free-plan sounds can break that.
• Watermarks and caps. Mirelo Free adds a watermark to exports and caps projects at 3. OpusClip Free adds a watermark and allows no editing.
• Features locked to higher plans. OpusClip's Auto SFX is not on Free or Starter, and Epidemic Sound's commercial and ad licensing starts at Pro.
• Attribution and claim risk. Freesound sounds can require credit, and its own FAQ warns that Content ID claims can occur. Check each sound's license.
• No manual override. Automatic placement is only useful if each effect can be removed, so look for per-effect volume, trimming and delete. OpusClip's help center describes all three for Auto SFX blocks.
• Unreadable prices. If a pricing page does not show an amount, treat it as unknown until a checkout page shows one.

Frequently asked questions

What is the best AI sound effects generator for video?

It depends on the job. For generating a specific sound from a text prompt, ElevenLabs is the better fit: it returns four samples per generation and lets the duration be set from 0.1 to 30 seconds. For sound generated from the picture of a finished edit, Mirelo is built for that. For sound effects added automatically on a video being clipped and captioned, OpusClip's Auto SFX is the pick, on the Pro plan.

How to add sound effects to video automatically?

In OpusClip, open a clip in the editor, choose Audio in the right sidebar, open the Auto SFX tab and click Auto generate sounds, or start from Auto SFX on the homepage. Per the help center, it analyzes the video, places effects as blocks on the timeline and takes under 2 minutes for a 60-second clip. Each block can be adjusted for volume and duration, or its prompt edited and regenerated. Auto SFX is on the Pro and Business plans. Mirelo also generates sound from an uploaded video of up to 10 minutes.

Is there a free AI sound effect generator?

Yes, with limits. ElevenLabs' Free plan lists 10,000 credits a month and includes Sound Effects, but allows non-commercial use only. Mirelo's Free plan lists 5,000 credits a month, 3 projects and a watermark on exports. OpusClip's Free plan does not include Auto SFX, which is on Pro and Business. For free library sounds rather than generated ones, Pixabay and Freesound cost nothing.

Royalty free sound effects for TikTok and Reels: where to find them?

Epidemic Sound's FAQ lists TikTok and Instagram among the places its sound effects can be used once the channels are connected, with commercial use needing Pro or above. Pixabay's license summary allows free use without attribution, subject to prohibited uses. Freesound sounds are free but carry Creative Commons licenses that differ per sound. ElevenLabs allows commercial use on paid accounts. Always read the license on the specific sound, since none of these pages is legal advice.

Can AI-generated sound effects be used commercially?

It depends on the tool and the plan. ElevenLabs says paid accounts can use its sound effects in commercial projects and that free users may only use the services non-commercially. For OpusClip, the pages we read do not state licensing terms for Auto SFX output, so check OpusClip's terms before relying on it for client work. Mirelo's pages we read did not include a licensing summary either.

Do automatic sound effects change the original audio?

In OpusClip, no: its help center says sound effects are placed on a separate track and can be removed at any time without touching the original footage, and each block can be deleted or regenerated without affecting the rest. Mirelo's site describes removing baked-in music while keeping dialogue, so how a tool treats the original audio varies and is worth checking.

Which OpusClip plans include Auto SFX?

Auto SFX, including generating a sound by prompt, is on the Pro and Business plans, per the OpusClip help center and tool page. Free and Starter do not include it. Pro is $29 a month, or $14.50 a month billed annually. See OpusClip pricing for the current plans.