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Education · head to head

Duolingo vs Stellarium

Duolingo logo

Duolingo

Education

Learn a language for free, forever

From
Free
Rated
-
Full reviewWebsite
Stellarium logo

Stellarium

Education

Free open source desktop planetarium software, distinct from the paid Stellarium Mobile Plus app

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Duolingo free tier includes ads and energy-based hearts system limiting daily practice without paying; Stellarium it is desktop-only software, so it has no native touch-optimised phone interface; the similarly named mobile app is a different paid product from a different company.
  • They diverge on capability: Duolingo covers 40+ languages, Stellarium covers Photorealistic sky rendering.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Duolingo and Stellarium actually diverge.

Attributes where Duolingo and Stellarium differ
AttributeDuolingoStellarium
Pricing modelUnknownOpen source, no licence fee
PlatformsiOS, Android, WebWindows, macOS, Linux
Founded2011Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Education).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Duolingo

  • 40+ languages
  • Gamification
  • Streaks
  • Leaderboards
  • Stories
  • Podcasts
  • Speaking exercises
  • AI tutor

Only in Stellarium

  • Photorealistic sky rendering
  • Large object catalogue
  • Telescope control
  • Scripting engine
  • Free and open source
  • Plugin ecosystem

What people use each for

The jobs each tool is most often brought in to do.

Duolingo

  • Language learningnot Stellarium
  • Travel preparationnot Stellarium
  • Career developmentnot Stellarium
  • Cultural explorationnot Stellarium

Stellarium

  • A student or educator wanting a serious, scriptable planetarium tool without a budget line itemnot Duolingo
  • An amateur astronomer wanting telescope control from desktop software they can inspect and modifynot Duolingo
  • Someone running a planetarium display or public astronomy event on a scripted shownot Duolingo
  • A hobbyist who wants a large object catalogue without paying a subscription, and does not need a phone appnot Duolingo

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Duolingo

  • Free tier includes ads and energy-based hearts system limiting daily practice without paying
  • Gamification focus may appeal to casual learners but lacks depth for serious language study beyond conversational basics
  • Limited to short, bite-sized lessons without extensive grammar explanations or cultural context

Stellarium

  • It is desktop-only software, so it has no native touch-optimised phone interface; the similarly named mobile app is a different paid product from a different company.
  • As a volunteer-maintained open source project, support is community-based rather than a guaranteed commercial help desk.
  • The interface, while capable, is less immediately intuitive for a first-time user than a polished commercial phone app.
  • Telescope control and some advanced plugins require additional setup that a non-technical user may find fiddly.
  • Because it shares a name with the unrelated paid Stellarium Mobile Plus app, buyers researching pricing online can easily conflate the two products.

Pricing, plan by plan

Duolingo

Free
  • FreeFree
    • All language courses
    • Ad-supported
    • Limited hearts (5-heart system)
  • Super$12.99/month
    • Ad-free
    • Unlimited hearts
    • Extra practice tools
  • Super Family$119.99/year
    • Up to 6 users
    • All Super features
    • Family group
  • Max$undefined/mo
    • All Super features
    • Video Call with Lily
    • Roleplay scenarios

Stellarium

Free
  • Stellarium DesktopFree
    • Full software, GPL licensed
    • No account, ads or subscription
    • Community-developed plugins

Which should you pick?

Choose Duolingo if

  • You need 40+ languages.
  • You want to start without paying.
  • You work on iOS, Android, Web.
  • You also want gamification.
Duolingo review

Choose Stellarium if

  • You need photorealistic sky rendering.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want large object catalogue.
Stellarium review

Questions people ask

Is Duolingo or Stellarium better?
Neither clearly leads. Duolingo starts at Free and Stellarium at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Duolingo or Stellarium?
Duolingo starts at Free and Stellarium at Free.
Does Duolingo or Stellarium run on more platforms?
Duolingo runs on iOS, Android, Web. Stellarium runs on Windows, macOS, Linux.
Can I use Duolingo for free?
Both have a free tier, so you can try either at no cost before committing.
What is Duolingo best used for?
Duolingo is most often used for language learning, travel preparation, career development, cultural exploration. Of those, language learning and travel preparation are not what Stellarium is typically brought in for.
What can Duolingo do that Stellarium cannot?
Duolingo covers 40+ languages, Gamification, Streaks, Leaderboards. Stellarium covers Photorealistic sky rendering, Large object catalogue, Telescope control, Scripting engine.

Answered from the vendors’ own pages

Duolingo: What is Duolingo's pricing model?

Duolingo offers free tier with ads and limited features, Super Duolingo at $12.99/month (ad-free, unlimited hearts, extra practice), Super Family at ~$119.99/year for up to 6 users, and Duolingo Max with AI features like Video Call and Roleplay.

Source
Stellarium: Is Stellarium really free?

The desktop software is free and open source under the GPL licence. The separate mobile app, Stellarium Mobile Plus, is a different paid product.

Duolingo: Is Duolingo effective for language learning?

Duolingo has 135+ million monthly active users as of Q3 2025, making it the world's most widely used language-learning app. Its gamified approach and free tier have driven massive adoption.

Source
Stellarium: Is the mobile app made by the same team?

No. Stellarium Mobile Plus is built by Noctua Software, a different company, and is sold on subscription.

Duolingo: What AI features does Duolingo Max include?

Duolingo Max includes Video Call for conversation practice with AI character Lily and Roleplay for scenario-based speaking practice. As of January 2026, Explain My Answer became free for all users.

Source
Stellarium: What platforms does the free version run on?

Windows, macOS and Linux desktop.

Duolingo: Does Duolingo work offline?

Duolingo is primarily online, though it may offer limited offline lesson downloads on some platforms. Full features require internet connection.

Source
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