Free · Chat & research · 7 of 7 tools · updated Oct 17, 2026
Free AI tools for deep research & AI search
ChatGPT is the strongest tool for deep research & AI search you can use without paying, at 74/100. What you get for nothing: Plus $20/mo, Pro $200/mo. 7 of the 7 tools tracked for this job have a free tier, an open-source licence, or are free outright. It is also the top-ranked tool for this job overall, free or not.
Same evidence score as the ranking — GitHub stars, Hacker News mentions, release activity, free access — recomputed nightly, never sold. See all 7 tools for deep research & AI search.
Top 3
evidence / 100
+ The broadest feature set in one place: Deep Research, code-executing data analysis on uploaded spreadsheets, voice mode and a huge library of custom GPTs.
− Free and Plus tiers hit message caps on the best models at busy times, and answers can be confidently wrong without citations unless you ask it to search.
+ Deep Research produces long cited reports from dozens of sources, and it reads your Gmail, Drive and Calendar directly when you allow it.
− Quality swings between Flash and Pro models, and it refuses or hedges on some topics more than competitors.
+ Every answer comes with clickable sources, and Pro lets you switch between frontier models from OpenAI, Anthropic and Google.
− Citations sometimes do not actually support the sentence they are attached to, so you still have to click through for anything important.
All 7, side by side
| Tool | Score | Pricing | What you get free | Platforms |
|---|---|---|---|---|
| ChatGPT | 74 | Free tier | Plus $20/mo, Pro $200/mo | web, mac, windows, ios, android, api |
| Gemini | 70 | Free tier | Google AI Pro $19.99/mo | web, ios, android, api |
| Perplexity | 53 | Free tier | Pro $20/mo | web, mac, windows, ios, android, api, chrome-extension |
 Consensus | 44 | Free tier | Premium from $8.99/mo | web |
 Grok | 34 | Free tier | SuperGrok $30/mo; also bundled with X Premium+ | web, ios, android, api |
 SciSpace | 9 | Free tier | no limits published | web, chrome-extension |
 Elicit | 8 | Free tier | Plus from $12/mo | web |
A free tier counts, and so does an open-source licence you can self-host — both are in the table, so a tool that is only free for a trial is not here.
Head to head: ChatGPT vs Gemini ChatGPT vs Perplexity Gemini vs Perplexity