Hearts are out, Energy is in. Duolingo replaced its famous 5-heart system with a battery-style Energy meter — and free users are split. Some love that mistakes no longer kill a session; others miss the old simplicity.
This guide explains the Duolingo Energy system: how it works, the exact numbers, how to refill it free, how it differs from Hearts, and the playbook for never running out.
How Energy Works: The Numbers
| Mechanic | Detail |
|---|---|
| Starting energy | ~25 units at the start of the day |
| Cost per question | 1 unit per question — right or wrong |
| Earning energy | Streaks of correct answers earn bonus energy (+1–5 per 5-correct streak) |
| Mistake review | Reviewing mistakes at lesson end costs nothing |
| Natural recharge | Full recharge in about a day |
| Rewarded ad | +3 to +5 energy (varies by test group) |
| Gem refill | 750 gems for a full refill |
Energy vs Hearts: What Changed
| Hearts (old) | Energy (current) | |
|---|---|---|
| Resource | 5 hearts | ~25 energy units |
| Lost on | Every mistake | Every question (right or wrong) |
| Beginner experience | Beginners 2× more likely to run out mid-lesson | Mistakes don’t end sessions |
| Skill rewarded | Accuracy (avoid mistakes) | Consistency (correct-answer streaks) |
Duolingo’s rationale: under Hearts, beginners were twice as likely to run out mid-lesson — the people who most needed practice got cut off first. Energy, the company says, helps more learners actually finish lessons.
How to Refill Energy (Free Methods)
- Correct-answer streaks — the main engine: chain 5 correct answers for +1–5 energy
- Rewarded ads — +3 to +5 energy per ad when you’re running low
- Treasure chests — occasional energy drops
- Practicing old material — some user groups earn energy this way
- Wait — full natural recharge in about a day
- 750 gems — the paid instant refill (see the math below)
Gem Economics: Is the 750-Gem Refill Worth It?
750 gems is steep — it can take a week or more of casual play to earn. The math says: watch the ad instead unless you’re mid-streak and every minute counts. Ads give +3–5 energy for 30 seconds; gems are better saved for streak freezes and other shop items.
The Web Workaround Nobody Leads With
The “Never Run Out” Free-Play Playbook
- Chase 5-streaks deliberately — slow down on hard questions; the streak bonus is your income
- Do shorter sessions — several short bursts earn more streak bonuses than one marathon
- Always review mistakes at lesson end — it’s free and prevents repeat errors
- Stack chests and practice sessions before starting new material
- Keep a streak freeze equipped — protecting the streak protects your gem income
Why Some Users Hate It
The backlash was real: a 700-day streak holder publicly quit over the change, a Reddit thread hit ~3,000 upvotes, and a poll of 11,000+ learners found about half dislike Energy. Free users report hitting the cap after just 2–3 perfect lessons on bad days. Note that Duolingo A/B tests everything — recharge amounts and earn rules vary between user groups, which is why your app may look different from your friend’s.
FAQs
Do you lose energy for wrong answers on Duolingo?
No. Energy costs 1 unit per question regardless of accuracy. Wrong answers only mean you miss the correct-answer streak bonus.
How do I get unlimited energy on Duolingo for free?
There’s no legitimate unlimited-Energy hack for free mobile users — but Super/Max subscribers get unlimited Energy, and desktop web still uses Hearts, effectively letting you learn without the meter.
How much energy do you start with?
About 25 units at the start of the day (community-measured; Duolingo doesn’t publish the exact figure and A/B groups vary).
Is the Energy system permanent?
All signs point to yes — it rolled out broadly through late 2025 after April–May testing, and Duolingo frames it as the intended long-term mobile model.
Why does my friend still have hearts?
Duolingo runs A/B tests continuously — some accounts still see Hearts, and the web version never switched. Your app may update to Energy at any time.
Energy running low? A Max family plan splits unlimited Energy 6 ways — or learn how Duolingo’s ads platform ties rewarded ads to Energy.
