Short answer: both turn a script into a talking-head video, and the paid decision hinges on who the avatar is. Synthesia leans toward polished stock avatars, brand kits, and corporate training at scale. HeyGen leans toward avatar cloning — you or your spokesperson, plus strong translation/dubbing of real footage. Pick Synthesia for standardized training content across a company; pick HeyGen when the person on screen needs to be a specific human. Credits meter both, so budget by video count, not by month.
The weekly-workflow test
- Same 60-second script in both — a real onboarding snippet or product explainer, not a demo script.
- Score first-render acceptance: of four avatars/styles per tool, how many look acceptable to show a customer?
- Test your face (if that's the plan): consented cloning in HeyGen vs stock-avatar polish in Synthesia — score realism honestly, with a viewer who isn't you.
- Test the localization job: render the same script in one other language you actually need; score lip-sync and accent acceptability.
Where each one wins
Synthesia
- Corporate training machine: templates, brand consistency, and review workflows for teams.
- Large stock-avatar and language library — coverage first.
- Enterprise controls and integrations for L&D departments; verified tiers on the review.
HeyGen
- Personal avatars and translation that keeps the original speaker on screen.
- Better for "the founder says it in six languages" content and repurposing real footage.
- Free tier is testable; credit tiers scale with output volume — current numbers on the review.
What overlaps — and the consent question that isn't optional
The slots are identical (script → avatar video), so paying for both needs a real split job: standardized training (Synthesia) vs personal-brand output (HeyGen). The bigger issue is consent: cloning a person's likeness requires that person's explicit, documented permission — employee, spokesperson, or client. Vendors provide consent flows; use them, keep records, and never clone someone from found footage. For commercial output, verify each vendor's current rights terms via our review pages before publishing.
Decision summary
- Company-wide training library: Synthesia.
- A specific human's face and voice, in many languages: HeyGen.
- Marketing localized at scale: whichever localization test you scored higher — run it before the annual plan.
- Anyone's likeness without their signed consent: neither. Full stop.
FAQ
Do these look real enough for customers?
For training and explainer content, yes — uncanny valley is mostly behind us in these tools. For hero marketing, test with real viewers; scores differ by avatar and voice.
Can I legally clone a colleague?
Only with their explicit consent, documented through the vendor's consent flow. Treat likeness like personal data — because it is.
Which is cheaper for 10 videos a month?
Credit structures differ; the only honest answer is to price your real monthly video count against the verified current tiers on Pricing Watch.
Related: HeyGen vs Synthesia comparison · HeyGen review · Synthesia review · Keep, Test, Cut