Every doubt app promises ‘unlimited doubts’, but unlimited is only cheap if you use it a lot. Let us calculate the actual cost per doubt for real usage.
Cost per doubt
| Doubts per month | Subscription ₹499/month | Subscription ₹999/month | Pay-per-question (₹49/100 credits) |
|---|---|---|---|
| 20 | ₹25 each | ₹50 each | ₹0.49 each (₹9.80) |
| 100 | ₹5 each | ₹10 each | ₹0.49 each (₹49) |
| 300 | ₹1.66 each | ₹3.33 each | ₹0.49 each (₹147) |
| 1000 | ₹0.50 each | ₹1 each | ₹0.40 each (₹99 packs) |
Hidden costs of subscriptions
- Auto-renewal in months you barely study (holidays, after exams).
- Paying in April for a service you needed in February.
- Family plans that charge for siblings who do not use it.
When a subscription is better
- You ask 30+ doubts every single day.
- You want a live human tutor, not AI.
- Your parents prefer one fixed bill.
When pay-per-question is better
- Usage varies week to week (most students).
- You use free resources first and need AI only for leftovers.
- You want the explanation in Bengali, Tamil or Hinglish.
- You do not want anything that renews on its own.
Common mistakes
- Comparing plans by monthly price instead of cost per doubt
- Ignoring what happens to unused credits (on DoubtPay AI they stay)
Related: best doubt solving apps.
Stuck on a study question?
Type the exact question (or attach a photo), choose your class or exam and your language — Hindi, Hinglish, English or 9 more — and ask your doubt on DoubtPay AI. You get step-by-step working with a labelled diagram where it helps, and you can ask for a hint, an attempt check, practice questions or flashcards instead. No subscription: packs start at ₹9 for 15 answers, unused credits stay in your account.
Stuck on a question? Ask it here and get a step-by-step answer in seconds — pay only per answer, no subscription. Ask your doubt now →
Frequently asked questions
Is DoubtPay AI free to try?
You can try the animated tutor demo without logging in. Answers use credits, and the smallest pack is ₹9 for 15 answers. Failed answers refund the credit.
Which languages and exams does DoubtPay AI support?
Hindi, Hinglish, English, Bengali, Marathi, Tamil, Telugu, Gujarati, Kannada, Malayalam, Punjabi and Odia, for Class 6–12 (CBSE, ICSE, state boards), JEE, NEET, CUET, SSC, banking, railways, UPSC and state PSC.
Do credits expire or renew automatically?
There is no subscription and nothing renews automatically. Unused credits stay in your account while the service runs, and answers are kept in your history for 90 days.
Stuck on a question? Ask it here and get a step-by-step answer in seconds — pay only per answer, no subscription. Ask your doubt now →