By the end of this guide you will have a set of custom sound effects, such as footsteps, a door creak or a power-up chime, created from a written description and downloaded as audio files ready to drop into a video, game or podcast. An AI sound effect generator does the work: you describe the sound, the tool returns one or more takes, and you keep the one that fits.
If you want to make sound effects with AI, the key decisions are the tool type (a text-only generator, a video-aware tool or a broader audio platform), the file format you need and the licence for your project. This guide walks through the steps and compares six tools from our Audio and voice category.
Key takeaways
- Describe the sound in plain words (source, surface, distance, mood), generate several takes, pick one, trim it in your editor and download it in the format you need.
- The main decision is the input: text prompts, or a video clip that the tool scores with effects that follow the action on screen.
- Free plans are mostly for trying a tool. Downloads and commercial use often need a paid plan, so check the licence before you publish.
- Layer and trim generated sounds. A single take rarely sounds finished against picture.
What you need before you start
- A list of the sounds you need. Write a short cue sheet: what happens on screen, and roughly how long each sound lasts.
- An account with your chosen tool. Some give a few free generations; SFX Engine, for example, lets new accounts try about five sounds without a card.
- An editor. Any audio or video editor to trim, layer and set levels.
- Time. Under an hour for a handful of effects, longer for a full game or film scene.
- Difficulty. Easy. Writing a good prompt is the main skill.
- A licence check. Know whether your project is personal or commercial before you pick a plan.
Which kind of AI tool fits this job
Pick by how you want to describe the sound.
A text-to-sound-effect generator. SFX Engine takes a plain-words description, returns up to four takes in roughly 5 to 15 seconds, each up to 47 seconds long, and downloads as royalty-free WAV. OptimizerAI generates sound effects from text, offers a Variation tool for similar sounds, and downloads as MP3, or WAV and FLAC on higher plans.
An audio platform with sound effects included. ElevenLabs generates music and sound effects from text prompts alongside speech, dubbing and voice tools, all drawing on one credit pool. Beatoven.ai is mainly a background-music generator, but its maestro Sound Effects feature creates foley-style effects from a prompt.
A tool that scores video. Sonilo offers video to sound effects, which adds Foley and ambience that follow the action on screen, as well as text to sound effects and music. It suits editors who would rather upload a clip than write every cue by hand.
A music-and-sound generator for producers. Stable Audio generates and edits music and sound effects from text prompts, with a tape-style deck (its multi-track mode is labelled experimental), a DAW plugin and an API. It leans toward producers who want to shape sounds in a session.
Step 1: List the sounds you need
You end this step with a cue sheet you can work through.
- Watch your scene or read your script and mark each moment that needs a sound.
- For each cue, note the source, the surface or space, and how close it is.
- Note the length. Short stings and long ambiences need different prompts.
- Group related cues so you can generate them in one sitting.
Check it worked by having a numbered list of cues with a rough length for each.
Step 2: Choose a tool and check the licence
You end this step with a plan that lets you use the sounds the way you intend.
- Decide whether the project is personal or commercial. Sonilo's Free plan output is for personal, non-commercial use with preview-quality exports, and commercial rights depend on the plan active when the audio was generated.
- Check whether you can download on the free tier. SFX Engine has no ongoing free plan, and downloads and commercial use need a paid plan.
- Check the format. SFX Engine downloads WAV, and OptimizerAI gives MP3 on Starter with WAV and FLAC on Pro and Unlimited.
- Use the comparison table below for pricing and stated limits.
Check it worked by being able to say which plan you need and what format it exports.
Step 3: Write a clear prompt
A specific prompt gives a usable first take.
- Name the sound source, such as "boots on gravel" or "power-up chime".
- Add the setting and mood, for example "inside a stone corridor, slow and heavy".
- State the length you need, and ask for one sound per prompt rather than a whole scene.
- Avoid music or speech in an effects prompt. SFX Engine notes it is not built for full songs, melodies or vocals as sound effects.
Check it worked by reading the prompt to someone and having them picture the sound.
Step 4: Generate several takes and pick one
Treat the first output as a draft, not a final.
- Generate the sound and listen on headphones.
- Compare takes. SFX Engine returns up to four takes per prompt, so you can choose the one that fits.
- Use variations when a take is close. OptimizerAI's Variation tool creates five similar sounds for five credits.
- If the sound is wrong, change one thing in the prompt, such as the surface or distance, and try again.
Check it worked by choosing a take that fits the on-screen action without explanation.
Step 5: Match sounds to picture
For video, the timing and the context matter as much as the sound.
- Try a video-aware tool for scene-wide sound. Sonilo's video to sound effects adds Foley and ambience that follow the action on screen.
- Otherwise, place each effect on a timeline against the picture.
- Layer two or three sounds for richer effects, such as a low thud under a metallic clang.
- Keep existing speech clear. Sonilo lists audio ducking among its tools, and editors can lower the effects under dialogue.
Check it worked by watching the scene with the sound on and noticing no effect that feels out of place.
Step 6: Trim, level and export
Finish by cleaning each sound and saving it in the right format.
- Trim silence from the start and end, and add short fades to avoid clicks.
- Set levels so effects sit below dialogue and above ambience.
- Export in the format your project needs, such as WAV for editing or MP3 for light use.
- Name files by cue, and keep the prompt, tool and plan in a notes file.
Check it worked by importing the files into your project and playing the full scene.
Step 7: Record the licence and ownership
A short record protects you if a client or platform asks.
- Save the plan details and the date you generated each sound. Sonilo ties commercial rights to the plan active at the time.
- Check the ownership rules. OptimizerAI says you own the sounds you create, even after you downgrade or cancel, but you cannot resell them as standalone products.
- Keep the licence wording for clients who need it.
- Do not publish generated sounds as a sound pack unless the terms allow it.
Check it worked by being able to point to the written terms for each sound you used.
Tools for this job compared
| Tool | Good fit for | Pricing | Stated limits |
|---|---|---|---|
| ElevenLabs | Sound effects alongside speech and music (web, API) | Freemium, paid from $6/mo (checked 24 Oct 2026) | Free plan: 10,000 credits per month, no rollover; creative products share one credit pool |
| Stable Audio | Music and effects with a multi-track deck and DAW plugin (web, API) | Pricing unknown | A session holds a maximum of 4 active tracks; multi-track mode and stem export are experimental; plan prices not shown |
| SFX Engine | Text prompts to royalty-free WAV, with up to four takes (web, API) | Paid, from $10/mo (checked 24 Oct 2026) | No ongoing free plan; free trial gives 15 credits; downloads and commercial use need a paid plan |
| Sonilo | Effects that follow the action in a video (web, API) | Freemium, paid from $14.99/mo (checked 24 Oct 2026) | Free output is personal, non-commercial and preview quality; film, television and studio games need Premium |
| Beatoven.ai | Music plus foley-style effects (web) | Paid | Non-exclusive licence; Beatoven.ai remains owner; plan details were not confirmed, so check its pricing page |
| OptimizerAI | Text-to-effect with variations (web, API) | Freemium, paid from $5/mo (checked 24 Oct 2026) | Starter allows one generation queue at a time; sounds cannot be resold as standalone products |
Prices and plan limits change, so confirm the current terms on each vendor's site before you subscribe.
Common mistakes to avoid
- Writing vague prompts. "A cool explosion" returns random results. Fix it by naming the source, space and mood, and by generating one sound per prompt.
- Using a free-plan sound commercially. Free outputs can be non-commercial or preview quality. Fix it by checking the licence before you publish, as with Sonilo's Free plan.
- Using a single take as final. One layer often sounds thin against picture. Fix it by layering and trimming in your editor.
- Burying dialogue. Effects that are too loud hide speech. Fix it by setting levels and ducking effects under voices.
- Reselling generated sounds. Terms may forbid it. Fix it by reading the ownership rules, such as OptimizerAI's ban on reselling sounds as standalone products.
How we put this together
This is an evidence-based guide built from each tool's listing in our directory, which is compiled from the vendor's own site and pricing page. It is not a review based on using the tools. We don't rank tools, and nobody paid to be included. Some outbound links may be affiliate links; see our disclosure.
Frequently asked questions
Can I make sound effects with AI for free?
Briefly. ElevenLabs' Free plan includes 10,000 credits per month, Sonilo's Free plan gives 2,000 credits every 2 weeks for personal use, and SFX Engine's free trial gives 15 credits. Free output is often limited to personal use, so check the licence before using it in a commercial project.
Can I use AI sound effects in a commercial project?
Only if your plan allows it. SFX Engine says downloads and commercial use need a paid plan, Sonilo starts commercial use on Pro and requires Premium for film, television, broadcast and studio games, and OptimizerAI lists commercial use on paid plans. Read the terms for your plan.
How long can a generated sound be?
It depends on the tool. SFX Engine lists takes up to 47 seconds long, and Stable Audio lists length options up to six minutes. Short effects are usually easier to get right, so build long ambiences from layers.
How long does it take to generate a sound effect?
SFX Engine says it returns up to four takes in roughly 5 to 15 seconds. Other vendors do not publish times, and prompting, listening and editing take longer than generation.
Can AI add sound effects to my video automatically?
Some tools can. Sonilo's video to sound effects adds Foley and ambience that follow the action on screen. Listen to the result and fix timing by hand, since automatic cues can miss details.
Compare more options in our Audio and voice category, or see how to get royalty-free background music with AI for the music side of a project.
