Photo by Raymond Aquila on Pexels
Both Synthesia and HeyGen turn a script into a talking AI avatar without filming anyone, but they've specialized in different directions — one leans into breadth of templates and languages, the other into fast dubbing and translation.
Synthesia — the widest template and avatar library
Synthesia has the deeper catalog of avatars and video templates, in dozens of languages, and has become the go-to for corporate training and explainer videos where you need a "presenter" without filming one. Pricing starts around $18/month.
HeyGen — faster translation and dubbing
HeyGen covers the same core ground — AI avatars — but adds fast video translation and dubbing that can take an existing video and produce a version in another language with matching lip movement, making it a stronger pick for marketing teams localizing existing content. A free tier is available, with paid plans starting around $24/month.
How the avatars actually look and sound
Both have crossed the point where a casual viewer usually assumes they're watching a real presenter, at least for short clips — lip-sync accuracy and natural pacing have improved a lot over the last couple of years. Neither is flawless yet: longer videos, unusual sentence structures, or a script with a lot of technical jargon can still produce a slightly uncanny cadence. Watch a full generated clip before committing to either for something client-facing, not just the first few seconds.
Custom avatars — a digital version of an actual person on your team, rather than a stock avatar — are available on both, usually as a paid add-on requiring a short video recording session to train the model. This matters if brand consistency requires the same "face" across every video rather than a generic presenter.
Where the cost difference actually shows up
Synthesia's higher entry price buys the deeper library and generally more polished output, which makes sense for a company producing a steady stream of training content where quality and variety compound over dozens of videos. HeyGen's free tier makes it the lower-risk way to test whether AI avatar video works for your use case at all, before deciding whether a paid plan on either platform is worth it.
Which one should you actually pick?
If you're producing training or explainer videos from scratch and want the widest choice of avatars and languages, Synthesia's library is the stronger foundation. If your real need is taking video content you already have and adapting it into other languages quickly, HeyGen's dubbing and translation focus is built specifically for that job.
Getting started without wasting your first attempt
Whichever you try first, write the script as if you're speaking it out loud before you generate anything — text that reads naturally when typed often sounds stilted once an avatar delivers it, since written and spoken sentence structure differ more than people expect. Both platforms let you preview and regenerate individual sections, so there's no need to get the whole script perfect before testing how it sounds.
Pricing breakdown: what you actually get at each tier
Both tools follow the same rough shape: a limited free or trial tier to test output quality, then a mid-tier plan aimed at individuals and small teams, then a business or enterprise tier with custom avatars, more monthly video minutes, and collaboration features. Synthesia's entry paid plan (around $18/month when billed annually) typically caps monthly video minutes and avatar access at a level that's fine for a handful of training videos a month but tight for a busy content calendar. HeyGen's free tier gives you a small allotment of credits to test avatar quality and dubbing before paying anything, with paid plans (around $24/month and up) unlocking longer videos, more avatars, and higher-resolution export. Neither publishes pricing that stays static for long, so treat these as ballpark figures and check the current pricing page before budgeting — enterprise tiers on both are quote-based and scale with seat count and usage volume.
Who each option is actually best for
Synthesia tends to fit organizations with a recurring need for polished, varied video content — HR teams producing onboarding modules, L&D teams building course libraries, or internal comms teams that need a consistent library of avatars across dozens of videos a year. The breadth of templates and avatars pays off most when you're producing volume, not a single one-off clip. HeyGen fits a narrower but very real job: taking video you've already made — a product demo, a founder pitch, a course lesson — and getting it in front of an audience that doesn't speak the original language, without re-shooting anything. Marketing and growth teams expanding into new regions get more direct value from that workflow than from a bigger avatar catalog. Freelancers and solo creators experimenting with AI video for the first time often start with whichever has a usable free tier, since the real question at that stage is whether avatar video fits the workflow at all, not which library is deeper.
Common mistakes people make choosing between them
The most common mistake is picking based on avatar catalog size alone without testing how either handles your actual script — technical terminology, acronyms, and non-English names can trip up pronunciation on both platforms, and that only shows up once you generate a real clip. Another is assuming dubbing output needs no review: automated translation and lip-sync are good but not perfect, and a native speaker should check tone and accuracy before a dubbed video goes out publicly, especially for marketing copy where phrasing matters. Teams also sometimes commit to an annual plan before confirming the monthly minute allotment actually covers their production volume — it's worth generating a realistic month's worth of content on a trial or lower tier first rather than estimating from a pricing page alone. Finally, don't assume a custom avatar (a digital version of a real team member) is instant — the recording and approval process for a trained avatar usually takes longer than people budget for before a launch date.
Limitations worth knowing before you commit
Neither tool is a replacement for filmed video in every scenario — product demos that need to show a physical object or interface in detail, live-action B-roll, or anything requiring genuine human spontaneity (an interview, a reaction) are still better shot conventionally. Avatar gestures and expressions, while improved, still repeat from a limited set of animations, which becomes noticeable across a long video or a series watched back-to-back. Background music, sound design, and complex editing (cuts, transitions, overlays beyond basic text) are limited or absent on both, so you may still need a lightweight video editor downstream for anything beyond a straightforward talking-head clip. And because both are cloud-based subscription services, your video library and avatar training data live on their servers — worth checking each platform's data retention and usage policy if you're working with confidential scripts or a proprietary likeness.
Frequently asked questions
Can I use my own voice with these avatars? Both support voice cloning as part of custom avatar creation, or you can pair either with a dedicated voice tool like ElevenLabs for more control over the audio separately from the video.
Do I need any video editing skill to use these? No — both are script-in, video-out tools designed for people without editing experience. Basic customization (backgrounds, text overlays, pacing) is handled through simple menus rather than a timeline editor.
Is AI avatar video obvious to viewers, or does it pass as real footage? For short, well-scripted clips, many viewers won't clock it immediately — but most companies using these tools for training or marketing don't try to hide that it's AI-generated, since audiences are increasingly used to it and disclosure avoids any credibility risk.
Can I switch between the two later if my needs change? Yes — neither locks you into a proprietary file format for the finished video, so you can export from one and continue using the other without losing your existing content. You would need to rebuild any custom avatar on the new platform, though, since avatar training doesn't transfer between services.
Do these tools support languages beyond English? Both support dozens of languages for text-to-speech and avatar delivery, and HeyGen's dubbing feature specifically is built around taking one language in and producing another out. Coverage and voice quality vary by language, so preview a clip in your target language before relying on it for a real project.
Is there a meaningful difference in output resolution or video quality? Both export at standard HD or higher resolutions suitable for web and social use on paid tiers, with free or entry tiers sometimes capping resolution or adding a watermark. If broadcast-quality output matters, check the exact export specs on your intended plan rather than assuming top resolution is included by default.
Fitting avatar video into an existing workflow
Neither tool exists in isolation, so it's worth thinking about where the finished video actually needs to live before generating it. Training content built in Synthesia usually ends up inside a learning management system, and both platforms support standard export formats that drop into an LMS course module without extra conversion work. Marketing teams using HeyGen for localized versions of an existing video typically need those clips to match an already-published original in length and pacing, which means the source script should be written with that constraint in mind rather than adjusted after the fact. Teams publishing to YouTube or social platforms should also check each platform's caption and accessibility export options, since auto-generated captions from the avatar tool aren't always as accurate as a proper closed-caption file reviewed by a person. Building the export step into the plan from the start avoids a second round of editing once the video is already generated.
Localization is more than lip-sync
HeyGen's dubbing feature gets attention for matching lip movement to translated audio, but a genuinely usable localized video needs more than that alone. Cultural references, idioms, and even the pacing of a joke often don't translate directly, so a script written for one market can land oddly in another even with perfect audio and lip-sync. Numbers, dates, and currency formats also need actual localization, not just translation, and neither tool automatically catches that a price mentioned in dollars should become a local currency for a different region's audience. The practical approach is to have a native speaker in the target market review both the translated script and the finished video before it goes out, treating the AI dubbing as the mechanical last step rather than the whole localization job. Skipping that review is a common way a technically correct dub still reads as slightly off to a local audience.
What to test before committing to either platform
Run the same short script, ideally one with a proper name, a number, and an acronym relevant to your industry, through both tools on their free or trial tiers before deciding. This surfaces pronunciation issues early, since both platforms mispronounce industry jargon and unfamiliar names often enough that it's worth catching before a real project depends on it. Generate at least one longer clip too, not just a 15-second sample, since pacing and avatar naturalness can degrade over a longer script in ways a short demo won't reveal. If custom avatars matter to your use case, budget time for the recording and approval step on both platforms rather than assuming it's instant, since that process typically takes longer than generating a video with a stock avatar. And check how each platform handles a script revision after the avatar has already been generated once, since re-generating only the changed portion versus the whole clip affects both cost and turnaround time on a real production schedule.
Frequently asked questions, continued
Do these tools work well for live or interactive presentations? No, both generate pre-recorded video from a script rather than real-time avatar delivery, so they're suited to training modules, marketing clips, and recorded updates rather than live meetings or interactive sessions.
Can I edit a generated video after the fact without regenerating it? Basic trims and text overlay edits are usually possible within each platform's editor, but changing the spoken script requires regenerating that section of the avatar's delivery, not just a simple video cut.
How much does a custom avatar cost compared to a stock one? Custom avatars are typically an add-on tied to a higher plan tier or a separate fee on both platforms, reflecting the additional recording and model training involved, so budget beyond the base subscription price if a trained likeness is required.