Key Takeaways
- Grok 4, released by xAI on July 9, 2025, topped the Artificial Analysis Intelligence Index with a score of 73, ahead of GPT-5 (estimated ~70) and Claude Opus 4 series models.
- GPT-5, launched by OpenAI on August 7, 2025, scored 94.6% on AIME 2025 math and 74.9% on SWE-bench Verified, making it the strongest all-around performer at launch.
- Claude Opus 4 (as of mid-2026 reaching version 4.7) leads on agentic coding tasks, with SWE-bench Pro jumping from 53.4% to 64.3% and CursorBench scoring at 70%.
- Grok 4 supports a 256,000-token context window standard, while its Fast variant expands to 2 million tokens, the largest of the three at this tier.
- Pricing varies significantly: Grok 4 API costs $3/$15 per million tokens (input/output), GPT-5 launched at $0.625/$5 per million tokens, and Claude Opus 4 sits at $5/$25 per million tokens.
- Grok 4 Heavy scored 50.7% on Humanity’s Last Exam, the first model to breach that threshold, and achieved a perfect score on AIME 2025 in its Heavy configuration.
- Claude Opus 4 series excels at long document analysis, agentic tool use, and code agents, while Grok 4 holds an edge in real-time data access through deep X (Twitter) integration.
The AI reasoning landscape shifted dramatically in the second half of 2025. Three flagship models from three of the most competitive labs now sit at the top of every leaderboard: xAI’s Grok 4, OpenAI’s GPT-5, and Anthropic’s Claude Opus 4 series. Each brings a distinct philosophy, distinct strengths, and a distinct price tag.
If you are choosing a model for serious work, the differences matter. Grok 4 is built around reinforcement learning at an unprecedented scale, running on xAI’s 200,000-GPU Colossus cluster with a training pipeline that delivers 6x compute efficiency gains. GPT-5 unifies fast and slow reasoning in a single architecture, dynamically routing between a lightweight system and a deep-thinking chain based on query complexity. Claude Opus 4 doubles down on agentic reliability, long context, and coding environments that developers actually use every day.
This comparison covers all three models on the metrics that count for real workloads: reasoning depth, coding accuracy, context size, cost, and speed. The goal is to give you one clear, current reference point before you commit budget to any of these platforms.
Quick Comparison
| Feature | Grok 4 | GPT-5 | Claude Opus 4.7 |
|---|---|---|---|
| Release Date | July 9, 2025 | August 7, 2025 | April 16, 2026 |
| Developer | xAI | OpenAI | Anthropic |
| Context Window | 256K (Fast: 2M) | Not disclosed (large) | 1M tokens |
| API Input Price (per 1M tokens) | $3.00 | $0.625 (at launch) | $5.00 |
| API Output Price (per 1M tokens) | $15.00 | $5.00 (at launch) | $25.00 |
| AIME 2025 Score | 93% (Heavy: 100%) | 94.6% | ~92.8% |
| GPQA Diamond Score | 88% | ~85% | Competitive |
| SWE-bench Verified | 75% | 74.9% | 74%+ (Opus 4.7) |
| Humanity’s Last Exam | 50.7% (Heavy) | Strong performer | Competitive |
| Consumer Plan | SuperGrok $30/mo | ChatGPT Plus $20/mo | Claude Pro $20/mo |
| Real-Time Data | Yes (X integration) | Yes (web search) | Limited |
What is Grok 4?
Grok 4 is xAI’s fourth-generation flagship large language model, released on July 9, 2025, following a livestream announcement by Elon Musk. It was trained on xAI’s Colossus supercomputer, a 200,000-GPU cluster that xAI used to run reinforcement learning at a scale no commercial lab had attempted before. The training pipeline included innovations that increased compute efficiency by 6x compared to previous runs, which translated directly into benchmark gains across reasoning, math, and science tasks.
The model comes in two configurations. Standard Grok 4 handles most tasks with a 256,000-token context window and excels at web research, code generation, and multi-step reasoning. Grok 4 Heavy uses a four-agent collaborative architecture where multiple model instances work together on a single problem, which is why it achieved a perfect score on AIME 2025 and broke the 50% barrier on Humanity’s Last Exam. The Heavy tier is available through the SuperGrok Heavy subscription at $300 per month.
One structural advantage Grok 4 holds over its competitors is deep integration with the X platform (formerly Twitter), giving it access to real-time social data, trending topics, and live news in a way that other models cannot replicate natively. Grok 4 Fast, the cost-optimized variant, extends the context window to 2 million tokens and delivers output at 342 tokens per second, making it the fastest option in the xAI lineup. API pricing for standard Grok 4 is $3.00 per million input tokens and $15.00 per million output tokens, positioning it between the low-cost GPT-5 launch pricing and the premium Claude Opus tier.
What is GPT-5?
GPT-5 is OpenAI’s fifth-generation flagship model, launched on August 7, 2025. It is available through ChatGPT and the OpenAI API and also powers Microsoft Copilot. The headline architectural feature is a unified system that combines a fast lightweight model for routine queries and a deep-reasoning “GPT-5 Thinking” mode for complex problems, with an internal router that decides which mode to engage based on query type, complexity, and user intent. This design means users do not need to manually switch between modes the way they did with separate o-series and standard model releases.
GPT-5’s benchmark numbers at launch were impressive across every dimension OpenAI measures. It scored 94.6% on AIME 2025 (without external tools), 74.9% on SWE-bench Verified for coding, and 84.2% on MMMU for multimodal understanding. Perhaps the most practically useful statistic is the hallucination reduction: GPT-5 responses are approximately 45% less likely to contain factual errors than GPT-4o, and when the thinking mode is engaged, that figure improves to roughly 80% fewer errors compared to OpenAI o3.
Pricing at launch was aggressive: $0.625 per million input tokens and $5.00 per million output tokens for the base model. Subsequent versions in the GPT-5 family have moved to higher price points as capabilities expanded. GPT-5.2, for example, is priced at $1.75/$14 per million tokens, and GPT-5.5 sits at $5/$30 per million tokens. For users on ChatGPT Plus at $20 per month, GPT-5 access is included, making it the most accessible premium model by subscription price. The model also supports prompt caching with up to 90% discounts on cached input tokens, which benefits long document workflows significantly.
What is Claude Opus 4?
Claude Opus 4 is Anthropic’s flagship model line, first introduced in 2025 and continuing to evolve through 2026. The most recent release as of early 2026 is Claude Opus 4.7, launched on April 16, 2026, which Anthropic describes as its most capable generally available model with a step-change improvement in agentic coding over prior versions. The model builds on the Claude 4 series foundation that prioritized long context, coding accuracy, and tool-augmented reasoning.
The practical advances in Claude Opus 4.7 are measurable. SWE-bench Pro improved from 53.4% to 64.3% between versions, CursorBench (which tests performance inside real developer tools) reached 70%, and vision resolution tripled to 3.75 megapixels. The full 1 million token context window is available at standard pricing, and long-context retrieval was meaningfully improved. For comparison, Claude Opus 4.5 and 4.6 were already considered strong performers on Elo-scored expert task benchmarks, with Claude Opus 4.6 scoring 1606 Elo on expert tasks in head-to-head evaluations.
Pricing for Claude Opus 4.7 is $5.00 per million input tokens and $25.00 per million output tokens, consistent with earlier Opus 4 versions. Anthropic offers up to 90% savings through prompt caching and 50% savings through batch processing. One notable change with Opus 4.7 is a new tokenizer that may produce up to 35% more tokens from the same input text, which means real-world costs can differ from headline per-token rates. Consumer access is through Claude Pro at $20 per month or through the Anthropic API.
Feature-by-Feature Breakdown
Reasoning and Math Performance
On raw reasoning benchmarks, the three models are genuinely close, but Grok 4 Heavy holds the current crown at the extreme end. It scored 50.7% on Humanity’s Last Exam (text-only subset), the first model to exceed 50% on that benchmark, and achieved a perfect score on AIME 2025 in its Heavy multi-agent configuration. Standard Grok 4 scored 93% on AIME 2025. GPT-5 followed at 94.6% on AIME 2025, placing it above standard Grok 4 but below the Heavy variant. Claude Opus 4.5 benchmarks came in at approximately 92.8% on AIME 2025.
On GPQA Diamond, which tests graduate-level scientific reasoning in biology, physics, and chemistry, Grok 4 scored 88%, ahead of GPT-5 at approximately 85%. These numbers reflect performance as of mid-2025; subsequent updates to all three model families have continued to push scores higher. The Artificial Analysis Intelligence Index, which aggregates across 20 benchmarks, placed Grok 4 at 73, OpenAI o3 at 70, and Anthropic Claude Opus 4 at 64 as of the initial Grok 4 release, though Claude’s subsequent point releases have narrowed that gap.
For everyday reasoning tasks, such as multi-step logic, scientific question answering, and research synthesis, all three models perform at a level that exceeds what most users will need to stress-test. The differences become visible only on the hardest graduate-level and competition-math problems, where Grok 4 Heavy retains a meaningful lead.
Coding Ability
Coding is the tightest race of the three. On SWE-bench Verified, which tests real-world GitHub issue resolution, Grok 4 scored 75%, GPT-5 scored 74.9%, and Claude Opus 4 series models scored around 74% and above. By raw number, Grok 4 leads, but the margin is less than one percentage point.
Where Claude Opus 4 distinguishes itself is in developer tool integration. CursorBench, which measures performance inside the Cursor code editor, reached 70% for Claude Opus 4.7. Claude is the default model inside many agentic coding environments, including Cursor and Claude Code, meaning developers encounter it naturally in their existing workflows. Anthropic’s focus on agentic reliability, meaning the ability to complete long multi-step coding tasks without dropping context or making cascading errors, is reflected in the SWE-bench Pro score improvement from 53.4% to 64.3% between versions.
GPT-5 demonstrated strong coding capability with a separate Codex variant that scored 99% on AIME 2025 (a math reasoning test often used to proxy coding aptitude) and performed at 74.9% on standard SWE-bench. OpenAI also introduced GPT-5.2-Codex, a coding-specific variant aimed at developer workflows. For agentic computer use, GPT-5 scored 75% on OSWorld, just above the 72.4% human baseline, making it the strongest on desktop automation tasks among the three at that point.
Context Window
Context window size directly affects which use cases each model handles well. Claude Opus 4.7 supports the largest standard context window at 1 million tokens, available at normal pricing without a premium tier upgrade. This makes it the practical choice for large codebase analysis, book-length document review, or multi-document research tasks.
Grok 4 Fast extends to 2 million tokens, which is the largest raw number among the three, but this is a separate variant rather than the standard Grok 4 model. Standard Grok 4 operates with a 256,000-token context window. GPT-5’s context window specifications were not publicly disclosed with the same precision at launch, but the model handles long documents effectively through its caching and routing architecture.
For practical use, a 256K context window is sufficient for most tasks, but researchers working with entire research libraries, developers analyzing large monorepos, or legal teams reviewing lengthy contracts will find Claude Opus 4’s 1M token window removes constraints that the other two models still impose at their standard tier.
Pricing and Access
GPT-5 launched at the most competitive API price point: $0.625 per million input tokens and $5.00 per million output tokens. For consumer users, ChatGPT Plus at $20 per month includes GPT-5 access, making it the most affordable entry to a frontier-tier model by subscription cost. Subsequent GPT-5 family releases have raised the price, with GPT-5.5 reaching $5/$30 per million tokens, bringing it closer to Claude Opus pricing.
Grok 4 API pricing is $3.00/$15.00 per million tokens, with a SuperGrok subscription at $30 per month for consumer access. The Grok 4 Fast variant is dramatically cheaper through the API. For the Heavy multi-agent configuration, SuperGrok Heavy costs $300 per month, which prices it out of individual use and into team or enterprise territory.
Claude Opus 4.7 sits at $5.00/$25.00 per million tokens, the highest standard API price of the three. However, Anthropic’s prompt caching (90% discount on cached tokens) and batch processing (50% discount) options can bring costs down significantly for structured workflows. Claude Pro at $20 per month provides consumer access to the Opus models at the same price as ChatGPT Plus.
Speed and Efficiency
Speed is where Grok 4 Fast separates from the pack most dramatically. The Fast variant delivers 342.3 tokens per second with a time-to-first-token of 2.55 seconds, making it the fastest option among the three at high-output tasks. Standard Grok 4, which runs deeper reasoning, is considerably slower, with the Heavy multi-agent variant taking longer still on complex problems.
GPT-5’s internal routing system is designed to minimize unnecessary latency by engaging the fast model for simple queries and only switching to deep reasoning when needed. This adaptive approach means average response times stay low even though the model can run extended reasoning chains. Anthropic has not published specific tokens-per-second figures for Claude Opus 4.7 at the same level of detail, but the model’s throughput is generally considered adequate for agentic tasks rather than optimized for raw generation speed.
For latency-sensitive applications, Grok 4 Fast or GPT-5’s base mode are better choices than Claude Opus. For batch processing where throughput matters more than real-time speed, all three support efficient bulk-request workflows with caching discounts.
Who Should Use Which?
Choose Grok 4 if your work centers on real-time information retrieval, social media analysis, or competition-level math and science problems. The deep X integration provides live data access that neither OpenAI nor Anthropic can match natively. Grok 4 Heavy is the right choice for research teams that need the best available reasoning performance and can justify the $300/month SuperGrok Heavy subscription. Grok 4 Fast is worth considering for any high-volume API use case where speed and cost efficiency are priorities.
Choose GPT-5 if you want the broadest coverage across coding, writing, vision, and multimodal tasks from a single model without thinking too hard about which variant to use. The unified architecture with automatic routing between fast and thinking modes reduces the overhead of managing model selection. GPT-5 is also the best option for users already embedded in the Microsoft ecosystem through Copilot, and the ChatGPT Plus pricing at $20/month makes it accessible without an API commitment. The strong hallucination reduction numbers also make it a good fit for factual research and content where accuracy is critical.
Choose Claude Opus 4 if your use case is agentic coding, long-document analysis, or complex tool-use workflows. The 1M token context window at standard pricing, the consistent SWE-bench and CursorBench performance improvements, and the model’s track record inside developer tools like Cursor make it the preferred choice for engineering teams. Legal and research teams that need to process entire documents without chunking will find Claude Opus 4’s context window removes a practical bottleneck that the other two models retain at their standard tiers.
For enterprises running mixed workloads, a hybrid approach works well: use Grok 4 Fast for high-volume real-time tasks, GPT-5 for general chat and multimodal workflows, and Claude Opus 4 for deep coding and document work. All three expose APIs that can be orchestrated within a single product.
Verdict
There is no single winner in a comparison this close, which is a reflection of how competitive frontier AI has become. Grok 4 holds the edge on raw reasoning benchmarks at the Heavy tier and offers the largest context window through its Fast variant, but the Heavy configuration is expensive and the base model’s 256K context window trails Claude Opus 4. GPT-5 is the most well-rounded model with the strongest initial pricing and the best hallucination reduction figures, making it the default recommendation for general use. Claude Opus 4 is the most reliable choice for agentic coding, developer tooling, and long-context document tasks.
For most individual users and small teams, GPT-5 via ChatGPT Plus or the base API tier delivers the best value. For engineering teams, Claude Opus 4 is consistently the model that tools are built around. For researchers and power users who need the best possible reasoning performance and are willing to pay for it, Grok 4 Heavy is the current benchmark leader. Monitor updates closely: all three labs are on aggressive release cycles, and the rankings shift with every major version.
You can explore more comparisons of top AI models on this site, including a detailed look at DeepSeek vs Claude coding and a breakdown of Jasper vs Writesonic for AI writing tools.
Frequently Asked Questions
Is Grok 4 better than GPT-5 for reasoning?
Grok 4 Heavy scores higher on the hardest benchmarks, including a perfect AIME 2025 score and 50.7% on Humanity’s Last Exam. Standard Grok 4 and GPT-5 are very close, with GPT-5 scoring 94.6% on AIME 2025 versus 93% for standard Grok 4. For most users, the practical difference is minimal.
What is Claude Opus 4 and how is it different from Claude 3 Opus?
Claude Opus 4 is Anthropic’s fourth-generation flagship line, released in 2025, with substantially stronger coding, agentic tool use, and a 1 million token context window. Claude 3 Opus was the 2024 flagship and is no longer the top Anthropic model. By mid-2026, the Opus 4 line had reached version 4.7 with significant gains in SWE-bench Pro scores and vision resolution.
Is GPT-5 available to free users?
GPT-5 launched with availability for ChatGPT Plus subscribers at $20 per month. Free ChatGPT users may have limited or no access to GPT-5, depending on OpenAI’s current tier policy. The API is available to developers at $0.625/$5.00 per million tokens for the base version, with higher-capability variants at different price points.
What is Grok 4 Heavy and is it worth the cost?
Grok 4 Heavy uses a multi-agent architecture where four instances collaborate on a single task. It is the configuration that achieved a perfect AIME 2025 score and the 50.7% Humanity’s Last Exam result. Access is through SuperGrok Heavy at $300 per month. It is worth the cost for research teams and organizations that need the highest available reasoning capability, but it is overkill for most business and individual use cases.
How does Claude Opus 4 perform on coding compared to GPT-5?
On SWE-bench Verified, Claude Opus 4 and GPT-5 are nearly identical (74% vs 74.9%). Claude Opus 4 pulls ahead on CursorBench (70%) and SWE-bench Pro (64.3%), which test performance in real developer environments and more complex multi-file tasks. Claude is also more deeply integrated into tools like Cursor and Claude Code, which matters for day-to-day developer workflows.
Which model has the largest context window?
Claude Opus 4.7 supports 1 million tokens at standard pricing. Grok 4 Fast supports 2 million tokens, but this is a separate, faster variant rather than the full reasoning model. Standard Grok 4 uses a 256,000-token context window. GPT-5 supports large context but OpenAI has not published a specific number comparable to the others.
Can I use Grok 4 without an X Premium subscription?
Yes. Grok is available to all X users for free with rate-limited access, estimated at roughly 10 requests every two hours. SuperGrok at $30 per month provides higher limits and full Grok 4 access. The xAI API also provides programmatic access to Grok 4 at $3.00/$15.00 per million tokens without requiring an X subscription.
Which AI model is best for scientific research?
Grok 4 currently leads on GPQA Diamond (88%), which is the benchmark most directly tied to graduate-level scientific reasoning in biology, physics, and chemistry. GPT-5 scored approximately 85% on the same benchmark. For researchers who need to process large scientific literature sets, Claude Opus 4’s 1M token context window is a practical advantage that the others do not match at the standard tier.
The gap between Grok 4, GPT-5, and Claude Opus 4 is the smallest it has ever been between frontier models from different labs. That makes the choice more about workflow fit, ecosystem integration, and budget than about raw capability. Test all three on your actual tasks before committing to a platform, and revisit the comparison every quarter as each lab continues to ship new versions at a rapid pace. For a broader look at how AI tools are reshaping different categories, explore the Canva AI vs Adobe and other reviews on this site.
