ChatGPT vs Claude vs Gemini vs Grok: which AI should you actually use?

Six weeks. That's the entire window in which Claude Sonnet 5 (30 June), the GPT-5.6 family (9 July), Claude Opus 5 (24 July), Grok 4.6 (12 August) and Gemini 3.7 Flash (13 August) all shipped. If you searched for this comparison a month ago, half of what you read is now describing a model that's no longer the default. That churn is also why the search results for this exact query are dominated by Reddit threads and LinkedIn hot takes rather than anything resembling a maintained reference. Nobody's incentivized to keep a listicle current when the ground shifts every two weeks. This one is dated on purpose. Check that date before you trust any number in it.

Current models and pricing (18 Aug 2026)

Below is what each vendor currently ships, with per-million-token API pricing where it's published and consumer subscription tiers alongside it. API price is input/output per million tokens; consumer price is monthly.

Vendor    Flagship model(s)              API price ($/M in-out)   Context        Consumer free tier         Paid tiers
Claude    Opus 5 (everyday flagship)     $5 / $25                 200K            Sonnet 5 (free default)   Pro $20/mo ($17 annual)
          Fable 5 / Mythos 5 (top tier)   $10 / $50                 1M default      —                          Max 5x $100/mo, Max 20x $200/mo
          Sonnet 5 (free-tier default)   $2 / $10 (permanent)      200K            yes                        included in Pro+

ChatGPT   GPT-5.6 Sol (flagship)         ~$5 / $30                 ~1.05M / 128K   Luna only on free           Go $8/mo, Plus $20/mo (first Sol tier)
          GPT-5.6 Terra (mid)            ~$2 / $12                 —               —                          included in Plus
          GPT-5.6 Luna (free default)    ~$0.20 / $1.20            —               yes, unlimited text        Pro $100/mo or $200/mo

Gemini    Gemini 3.1 Pro (reasoning      not published for         1M / 64K        limited free tier          AI Plus $4.99/mo, AI Pro $19.99/mo
          flagship)                     consumer chat                                                        AI Ultra $99.99–199.99/mo (20TB storage)
          Gemini 3.7 Flash (coding/      $0.75 / $3.75 intro       —               —                          same tiers above
          agent workhorse, not a        (rises to $1.50/$7.50
          flagship replacement)         1 Jan 2027)

Grok      Grok 4.6 (Aug 12, consumer     from $2 / $6              500K (long-     via X Premium if/when      SuperGrok Lite $10/mo
          rollout unconfirmed)          rollout status              context above  rolled out                 SuperGrok $30/mo
          Grok 4.5 (confirmed on         at announcement            200K priced                                X Premium+ $40/mo
          consumer tiers)               time)                       separately)                                SuperGrok Heavy $300/mo (only tier
                                                                                                                 confirmed full top-model access)

A few things that table can't fully convey. Claude's $2/$10 pricing for Sonnet 5 was announced as permanent in an August 10 update, not an introductory rate that quietly resets later. That's worth noting because introductory-then-hiked pricing is common enough in this category that permanence is itself a fact worth stating. Gemini 3.1 Pro's API pricing wasn't published as a flat consumer-facing number at research time; Google prices it through its cloud platform rather than a simple per-token card the way the others do. And Grok 4.6's headline price is a floor ("from $2/$6") because it uses tiered long-context pricing once you cross 200K tokens: the number goes up from there, not down.

The naming problem nobody explains clearly

Two of the four vendors currently run three-tier naming schemes that genuinely confuse people shopping for a subscription, and it's worth untangling both before the comparison means anything.

Claude: Opus 5 vs Fable 5 and Mythos 5

This is a real point of disagreement even among sources that track Anthropic closely, so it's worth stating plainly rather than picking a side. Claude Opus 5, priced at $5/$25 per million tokens, is what most people mean when they say "Claude's flagship" today. It's the everyday-use model, and it's the one putting up the 96-97% SWE-bench Verified scores that get cited in coding comparisons. Claude Fable 5 and Claude Mythos 5, at $10/$50 per million, are Anthropic's own stated "most capable widely released" tier: they default to a 1M-token context window and can output up to 128K tokens in one response, both meaningfully larger than Opus 5's limits. So which one is "the" flagship depends on what you're optimizing for: Opus 5 for day-to-day coding and general use at half the price, Fable 5/Mythos 5 when you specifically need the largest context window or maximum output length Anthropic offers. Don't assume the higher price automatically means the better everyday choice; for most people it doesn't.

ChatGPT: Sol, Terra and Luna

OpenAI's GPT-5.6 family splits into three named tiers that map to a simple mental model once you know it: Sol is the flagship (full capability, priced ~$5/$30 per million, needs a Plus subscription or higher to reach in the consumer app), Terra is the mid-tier workhorse (~$2/$12 per million, good enough for most tasks at a fraction of the cost), and Luna is the fast, cheap model (~$0.20/$1.20 per million) that became the free-tier default on August 6, 2026 after an 80% price cut on July 30 made it viable to give away with unlimited text chat. If you're on ChatGPT's free tier today, you are talking to Luna, not Sol. That's a distinction that matters if you're benchmarking your own experience against a review that used Plus.

Which one wins, by task

Coding

Claude is the model developers reach for first right now, and the reasoning is only partly about raw benchmark scores. On SWE-bench Verified, Claude Opus 5 leads at 96-97% (independently verified by vals.ai at 97.0%), with GPT-5.6 Sol close behind at 96.2%. That's close enough that raw accuracy alone doesn't fully explain Claude's reputation lead. Claude Fable 5 scores 95.0%, GPT-5.6 Luna 93.0%, and Grok 4.5 trails the pack at 86.6%. For context, Kimi K3, a Chinese model outside this comparison, sits at 93.4%, a useful reminder that the gap between the leaders and the also-rans on this benchmark is smaller than the reputational gap. Neither Gemini 3.7 Flash nor Grok 4.6 has a published SWE-bench Verified score yet; both are under a week old at the time of writing, and any number you see claimed for them right now is either a leak or a guess. Gemini 3.1 Pro posted 76.2% SWE-Bench Verified at its own launch, meaningfully behind the leaders. Aggregated reviews consistently describe Gemini as the weakest of the four for coding, useful as a second opinion rather than a primary tool.

Writing

Claude is repeatedly cited as strongest for tone-adherence and natural long-form cadence. One head-to-head comparison had it taking half the rounds in blind testing against the other three; that's worth citing as a single test result rather than a universal law, but it lines up with the broader pattern in how reviewers describe Claude's prose versus the others' tendency toward a recognizably "AI-generated" rhythm. If you're drafting anything long-form where voice matters (essays, articles, editing your own writing without flattening it), Claude is the one people keep coming back to.

Research and document analysis

This one splits, and the split maps to two genuinely different jobs. Claude is cited for closed-context document reasoning (reading a fixed set of files and reasoning carefully within them) and for calibration, meaning it's more willing to say it doesn't know something than to guess. Gemini is cited for its raw 1M-token context window and native multimodal ingestion, meaning it can take in video and large document sets other models can't touch at all. If your job is "read this enormous pile of material and hold all of it in view at once," that's Gemini's advantage on paper. If your job is "answer carefully from a smaller, fixed set of sources without hallucinating," that favors Claude. See the note on Gemini's actual working memory further down, though: the 1M-token advantage doesn't fully reach the consumer chat product the way the spec sheet implies.

Real-time news and current events

This is the one category with no real debate. Grok wins decisively because it has direct, native access to live X data. Every source covering this space agrees, and it's the single clearest differentiator among the four. Claude has no native real-time data access at all; it relies on an optional web-search tool bolted on rather than baked in. ChatGPT has web browsing, but reviewers consistently describe it as less fluid and slower to surface breaking events than Grok's native X integration. If you want to know what's happening right now, not what happened as of a training cutoff plus a search-tool patch, Grok is built for that job specifically.

Image generation

Gemini and ChatGPT are both cited as the strongest image generators of the four. Gemini's specific edge is style consistency across a generation session: keeping the same character or aesthetic coherent across multiple images in one conversation, which is a real practical gap for anyone iterating on a visual concept. Claude deliberately generates no images, audio, or video at all. That's a design choice, not an oversight, since Anthropic has positioned Claude as a text-and-analysis product from the start, but it's a real limitation if visual generation is part of your workflow. Grok is described as "still catching up" on full multimodal generation relative to the other three.

Voice mode

A close three-way race with each product winning on a different axis. Grok Voice has the fastest raw latency in the category, 300-500ms, with prosody that reviewers describe as natural rather than robotic. ChatGPT's Advanced Voice Mode is rated the best pure conversational experience, running full-duplex audio so it can be interrupted mid-sentence the way a real conversation works. Gemini Live wins on ecosystem integration (it can pull from Calendar, Maps and Gmail mid-conversation) and on language coverage, supporting roughly 97 languages against Grok's roughly 25-plus. Claude has no comparable voice product in this comparison.

Memory

Each vendor built a genuinely different, non-interoperable memory system, and it's worth knowing they don't talk to each other before you build a workflow around one. ChatGPT's "Dreaming" (shipped June 2026) runs continuous background synthesis of your conversation history. Claude's "Chat Memory" (shipped March 2, 2026) runs a 24-hour synthesis cycle and, notably, is available on every plan including free: Anthropic didn't gate it behind Pro. Gemini's "Personal Intelligence" (renamed from "Personal context" on January 14, 2026) does something similar within Google's ecosystem. None of these export to or sync with each other. Switching assistants means starting your memory from zero, which is worth factoring in if you're already invested in one.

Documented weaknesses: the parts marketing pages skip

Every one of these products has a real, sourced problem worth knowing before you commit money or workflow to it. None of these are forum gripes dressed up as facts: each has a specific incident or measured gap behind it.

Claude

Rate limits are described as the single most complained-about aspect of the product. During a March 23-26, 2026 incident, Claude Code and Max-tier users reported their 5-hour session budgets draining in 60-90 minutes instead of lasting the full window. One Max 20x subscriber reported their usage jumping from 21% to 100% on a single prompt, and the Reddit thread documenting it collected over 1,060 upvotes. Beyond rate limits, the lack of any image, audio or video generation is a real gap for anyone who needs mixed media in one tool, not just a design footnote.

ChatGPT

The most serious documented case is a real, named hallucination incident: ChatGPT falsely stated that Norwegian citizen Arve Hjalmar Holmen had murdered his own children, an incident that became public and drew scrutiny specifically because it named a real, identifiable person in a fabricated and defamatory claim. Separately, over-refusal on benign queries has been a growing complaint: one cited example has the model refusing to explain how ibuprofen works, deflecting to "consult a medical professional" for a question that doesn't remotely require one. To OpenAI's credit, the company reported its GPT-5.5-Instant switch on May 5, 2026 cut hallucinations by 52.5%. That's worth noting because a cut that large implies the prior baseline was bad enough to need a public fix, not a routine tune-up.

Gemini

"1M-token context window" needs a second look before you rely on it in the consumer product. Paid Gemini subscribers report the consumer chatbot's actual working memory caps out around 16,000 tokens in practice (roughly 25 to 30 messages before it starts forgetting earlier parts of the conversation), despite Google advertising a 1M-token window on the spec sheet. Android Headlines, which reported this gap, notes it appears specific to the consumer chat surface: the same 1M-token window reportedly works as advertised on the developer-facing Google AI Studio product. If your plan for Gemini is "paste in a huge document and chat about it for a while" through the consumer app, that gap is worth testing yourself before you rely on it for anything long.

Grok

Grok carries real regulatory and moderation controversies, not just forum complaints. In July 2025, the model produced antisemitic output in an incident widely referred to as "MechaHitler," removed within 16 hours of surfacing. By mid-January 2026, Grok's image tools had been used to generate deepfake and non-consensual imagery seriously enough that it triggered the first national bans of a major AI model in some countries. Moderation since then has been inconsistent in both directions: sometimes harmful content gets through, sometimes ordinary prompts get blocked; one widely-shared r/grok complaint put it as "image generation is ruined, even bikinis are being censored." A paywall tightening in April 2026 also dropped the app's user rating sharply. On top of the moderation history, the community consensus is that Grok remains weaker at coding than Claude or ChatGPT, consistent with its 86.6% SWE-bench score above.

Where a document-specific tool still beats all four

None of these four general assistants is built primarily to answer from a fixed set of your own documents with a citation trail back to the exact passage. That's a different job from what they're optimized for, and it shows: ChatGPT and Grok answer mostly from training knowledge plus whatever you paste in; Claude and Gemini can take large uploads but don't make citation-per-claim the default behavior of the product. If your actual task is closed-source research (a stack of PDFs, a set of course readings, a folder of meeting transcripts) where you need every claim traceable to a specific line in a specific document, Gemini Notebook (the product formerly known as NotebookLM, renamed by Google in July 2026) is built around exactly that constraint in a way none of the four general assistants above are. It's not a replacement for any of them for open-ended writing or coding. It's a different tool for a different job, and a reasonable workflow uses both: verify facts in a grounded, citation-first tool, then take the verified synthesis into whichever general assistant fits the writing or analysis task at hand.

FAQ

Which AI is best overall in 2026?

There isn't one. That's the honest answer, not a dodge. Claude currently leads on coding and long-form writing quality, Grok is the only one with native real-time access to current events, and Gemini and ChatGPT lead on image generation. Pick based on your primary task, not a single aggregate score.

Which AI is best for coding right now?

Claude Opus 5 leads on SWE-bench Verified at 96-97%, independently verified by vals.ai at 97.0%. GPT-5.6 Sol is close behind at 96.2%, close enough that Claude's reputation edge in coding communities isn't purely about the benchmark number, but also about tooling like Claude Code. Gemini is consistently described as the weakest of the four for coding, useful as a second opinion rather than a primary tool.

Which AI is completely free to use?

All four have a free tier: Claude defaults to Sonnet 5, ChatGPT defaults to GPT-5.6 Luna with unlimited text chat since August 6, 2026, Gemini has a limited free tier, and Grok is accessible through the $8/mo X Premium tier at minimum for full access (X's basic free tier includes limited Grok access). None of the free tiers reach each vendor's actual flagship model.

Which AI has the largest context window?

On paper, Claude Fable 5 and Mythos 5 default to 1M tokens, matching Gemini 3.1 Pro's 1M input window. In practice, Gemini's consumer chat product reportedly caps real working memory around 16,000 tokens per Android Headlines. The full window works on Google's developer-facing AI Studio product but not consistently in the consumer app, so treat the advertised number with caution for everyday chat use.

Which AI can access real-time information and today's news?

Grok, unambiguously: its native X/Twitter data access is a differentiator every source covering this space agrees on. Claude has no native real-time access and relies on an optional web-search tool. ChatGPT has web browsing but reviewers describe it as less fluid than Grok's native integration.

What's the difference between GPT-5.6 Sol, Terra and Luna?

Sol is OpenAI's flagship (~$5/$30 per million tokens, needs Plus or higher), Terra is the mid-tier workhorse (~$2/$12 per million), and Luna is the fast, cheap model (~$0.20/$1.20 per million) that's been the free-tier default with unlimited text chat since August 6, 2026. Free-tier users are talking to Luna, not Sol.

Is Claude Opus 5 better than Claude Fable 5?

Depends what you need. Opus 5 ($5/$25 per million) is the everyday-use flagship and the one posting the top SWE-bench coding scores, at half the price of Fable 5/Mythos 5 ($10/$50 per million). Fable 5 and Mythos 5 default to a larger 1M-token context window and can output up to 128K tokens per response, part of Anthropic's own stated 'most capable widely released' tier. Most day-to-day use is better served by Opus 5; reach for Fable 5 or Mythos 5 specifically when you need the larger context or output ceiling.