Short answer: Energy is Duolingo's replacement for Hearts. Instead of losing a heart for each mistake, free learners now have a battery: each lesson uses some Energy, getting several answers right in a row earns some back, reviewing your mistakes at the end of a lesson is free, and the battery fully recharges in about a day. You can top it up with a rewarded ad or with gems. Super Duolingo subscribers get unlimited Energy, so the system never limits them. For most free learners Energy means fewer hard stops in the first lessons of the day, but heavy users still hit a daily cap that Hearts used to impose in a different way.
Why Duolingo Replaced Hearts
Under Hearts, every mistake cost free learners one heart, and running out ended the session until the hearts refilled. In its official explanation, Duolingo says this "was not the most effective way to support learning", especially for beginners, who were twice as likely to run out of hearts mid-lesson. The company says its data shows Energy "helps more learners complete lessons".
The switch was first reported by The Verge in May 2025, rolling out on iOS first and on Android later. Duolingo's blog post on Energy is dated July 3, 2025 and was last updated November 3, 2025.
How Energy Works for Free Learners
Duolingo describes Energy as a learning battery. According to its blog:
- You start with full Energy.
- Each lesson uses a little Energy.
- You earn Energy back when you get multiple answers in a row right.
- Reviewing your mistakes at the end of a lesson does not use Energy.
- Energy fully recharges in about a day.
- When you run low, you can watch a rewarded ad or buy a refill with gems.
- Bonus Energy comes from perfect lessons, adding a friend and reward chests.
At launch, Duolingo told The Verge that a full bar holds 25 units (compared with five hearts), that each exercise costs one unit and a mistake costs one more, and that streaks of correct answers return Energy at a randomised rate. Duolingo also says Energy "is being actively tested and will improve over time", so exact numbers in your app may differ.
Hearts vs Energy at a Glance
| Feature | Hearts (old) | Energy (current) |
|---|---|---|
| What it measures | Mistakes | Activity, with mistakes costing extra |
| Full amount at launch | 5 hearts | 25 units (as reported in May 2025) |
| Correct answers | No effect | Streaks of correct answers earn Energy back |
| Running out | Session ends, often in the first lesson for beginners | Session ends after more lessons, at a daily cap |
| Refill | Over time, ads, gems | Full recharge in about a day, ads, gems |
| Super Duolingo | Unlimited hearts | Unlimited Energy |
How Energy Works for Super Subscribers
Paid learners are not affected. Duolingo's US App Store listing (checked November 10, 2026) advertises Super Duolingo with "Unlimited Energy & Monthly Streak Repair" and a 14-day free trial, and lists Super purchases from $9.99 to $119.99 depending on plan and billing period. Duolingo's 2026 shareholder letters say Duolingo Max is being phased out and its Video Call feature is moving into Super; our Duolingo Video Call review covers that change.
Does Energy Change How Much You Can Practise Each Day?
It depends on how you use the app.
| Learner type | Effect of Energy |
|---|---|
| Beginner, 1 to 3 lessons a day | Better than Hearts: mistakes no longer end the session early |
| Accurate intermediate learner | Correct-answer streaks refill Energy, so you can usually do more |
| Heavy free user, long sessions | You hit a daily cap based on activity, not just errors; ads or gems extend it |
| Super subscriber | No limit |
The honest summary: Energy rewards accuracy and short daily sessions, and it caps marathon sessions for free users. For language learning that is not a bad trade, because spaced daily practice beats occasional long sessions. A meta-analysis of distributed practice studies by Cepeda and colleagues (2006) found that spreading practice over time improves long-term recall compared with massing it into one session.
How to Get the Most From Energy Without Paying
- Do one lesson before anything else. A full battery each day means your first lessons are the safest.
- Slow down on new material. Accuracy streaks earn Energy back, so careful answers last longer than fast guesses.
- Always review mistakes at the end. It is free and it is where most learning happens.
- Practise speaking outside Duolingo. Energy only limits Duolingo lessons. Ten minutes of speaking with a free tool such as ChatGPT voice prompts or a dedicated speaking app adds the skill Duolingo lessons train least.
If you mostly need speaking practice rather than more lessons, a speaking-first AI tutor may be a better use of a subscription than Super. Enverson AI, for example, focuses on unscripted conversation with per-session measurements; our Find Your Fit tool compares options by goal.
Frequently Asked Questions
Did Duolingo get rid of Hearts?
Yes. Duolingo replaced Hearts with Energy, rolling out on iOS from May 2025 and on Android later. Duolingo says the change helps more learners complete lessons.
How long does Duolingo Energy take to refill?
Duolingo says Energy fully recharges in about a day. You can refill sooner by watching a rewarded ad or spending gems, and you earn some back by answering several questions in a row correctly.
Do mistakes still cost anything?
Yes, but less harshly. At launch Duolingo said each exercise uses one unit of Energy and a mistake uses one more. Reviewing mistakes at the end of a lesson is free.
Does Super Duolingo have unlimited Energy?
Yes. Duolingo's App Store listing advertises Super Duolingo with Unlimited Energy, checked November 10, 2026.
Is Energy better or worse than Hearts?
Better for beginners and accurate learners, who can do more lessons before stopping. Worse for free users who like long sessions, because Energy also drains with activity, not only with mistakes.
Sources
- Duolingo Blog: Why Duolingo switched to Energy and how it helps you learn
- The Verge: Duolingo is replacing hearts with energy (May 12, 2025)
- Duolingo on the US App Store
- Cepeda et al. (2006), Distributed practice in verbal recall tasks, Psychological Bulletin