ChatGPT GPT-5 vs Claude Fable 5: SWE-Bench 72.7%, $10/M Tokens

ChatGPT, Claude, Gemini, and Grok are the four AI models most developers and knowledge workers use daily in 2026. Each has different strengths, pricing, and the gap between them has narrowed significantly. This comparison covers benchmarks, pricing, coding, writing, and reasoning so you can pick the right one without guessing.

## The One-Line Summary

**Claude** wins for coding and long-form writing. **Gemini** wins for context size and Google integration. **ChatGPT** wins for ecosystem breadth and general use. **Grok** wins for real-time data and cost. Most serious users need two of these, not one.

## June 2026 Update: Claude Fable 5 Raises the Ceiling

Anthropic released **Claude Fable 5** on June 9, 2026: the first publicly available Mythos-class model and, per Anthropic, state-of-the-art on nearly all tested benchmarks. Three things change for this comparison:

- **Long-horizon coding.** Stripe reported Fable 5 migrated a 50-million-line Ruby codebase in a day, a job estimated at two-plus months for a human team. On Cognition's FrontierCode benchmark it posted the highest score among frontier models, even at medium reasoning effort.
- **Pricing.** $10 per million input tokens and $50 per million output. That is premium-tier pricing, above Sonnet 4.6 ($3/$15) but less than half of Mythos Preview. Track it against the rest of the market on the [LLM API Pricing tracker](/tools/llm-api-pricing).
- **The fallback caveat.** Queries touching cybersecurity, biology, chemistry, or distillation route to Claude Opus 4.8 in under 5% of sessions, with a notice when it happens. Agent builders should plan for mixed model identity in long runs.

The verdict table below still holds for everyday $20/month use; Sonnet 4.6 remains the default Claude workhorse. But for multi-hour autonomous coding, Fable 5 is now the strongest option on the market. Full breakdown: [Claude Fable 5 launch: what shipped and what stays gated](/blog/anthropic-claude-fable-5-mythos-class-launch-opus-fallback-june-2026).

## Current Models

| Provider | Model | Context Window | Released |
|----------|-------|---------------|---------|
| OpenAI | GPT-5 / GPT-4o | 128K | 2026 |
| Anthropic | Claude Sonnet 4.6 | 200K | 2026 |
| Google | Gemini 3 Pro | 1M tokens | 2026 |
| xAI | Grok 3 | 131K | 2025 |

## Benchmark Comparison

| Benchmark | GPT-4o | Claude Sonnet 4.6 | Gemini 3 Pro | Grok 3 |
|-----------|--------|-------------------|--------------|--------|
| MMLU | 88.7% | 88.3% | 87.8% | 87.5% |
| HumanEval (coding) | 90.2% | 93.7% | 88.5% | 88.0% |
| MATH | 76.6% | 78.2% | 79.4% | 75.8% |
| GPQA (graduate reasoning) | 53.6% | 65.0% | 72.5% | 56.0% |
| SWE-Bench Verified | 49% | 72.7% | 51% | 45% |

Claude leads on coding (SWE-Bench 72.7% vs GPT-4o's 49%) by a large margin. Gemini leads on graduate-level reasoning. GPT-4o leads on MMLU by a small margin. Grok trails on most benchmarks but is competitive for general tasks.

## Pricing: Subscriptions

| Plan | ChatGPT | Claude | Gemini | Grok |
|------|---------|--------|--------|------|
| Free tier | Yes (GPT-4o limited) | Yes (limited) | Yes (limited) | Yes (limited) |
| Standard | $20/month (Plus) | $20/month (Pro) | $20/month (Advanced) | $22/month (X Premium+) |
| Power user | $200/month (Pro) | $100/month (Max) | $30/user (Enterprise) | — |

## Pricing: API (per million tokens)

| Model | Input | Output |
|-------|-------|--------|
| GPT-4o | $2.50 | $10.00 |
| GPT-4o mini | $0.15 | $0.60 |
| Claude Fable 5 | $10.00 | $50.00 |
| Claude Sonnet 4.6 | $3.00 | $15.00 |
| Claude Haiku 4.5 | $0.80 | $4.00 |
| Gemini 3 Pro | $1.25 | $5.00 |
| Gemini Flash | $0.075 | $0.30 |
| Grok 3 | $3.00 | $15.00 |
| Grok 3 Mini | $0.30 | $0.50 |

For cost-sensitive API workloads: Gemini Flash ($0.075 input) and GPT-4o mini ($0.15 input) are the cheapest capable options. Claude Haiku offers the best value in the Anthropic family.

## ChatGPT in 2026

ChatGPT is the most widely used AI product in the world with over 400 million weekly active users. Its strength is breadth — it handles writing, analysis, code, image generation (DALL-E), voice, and file uploads in one interface.

GPT-5 (released in early 2026) improved significantly on reasoning and instruction following compared to GPT-4o. The API ecosystem is the most mature, with the widest third-party tool support.

**Where it wins**: General-purpose workbench, file analysis, mixed workflows, ecosystem breadth, familiarity.

**Where it loses**: Coding depth (Claude beats it significantly on SWE-Bench), context window (smaller than Gemini), cost at scale.

## Claude in 2026

Claude Sonnet 4.6 holds the highest SWE-Bench Verified score of any major model at 72.7% — meaning it solves nearly three quarters of real GitHub issues autonomously. For developers, this is the most practically meaningful benchmark.

Claude also leads on long-form writing quality. Its instruction-following is the most precise of the four — it does what you ask without adding unnecessary content, hedges, or refusals. The 200K context window handles large codebases in a single session.

Claude Code (the agentic coding tool built on Claude) is the fastest-growing developer tool in 2026, with companies like Stripe, GitLab, and Goldman Sachs using it for production code tasks. Since June 9, the premium tier is Claude Fable 5, which extends the lead on long-horizon agentic work (see the June 2026 update above).

**Where it wins**: Coding (best SWE-Bench), long-form writing, instruction following, agentic coding tasks.

**Where it loses**: No real-time search by default, smaller context than Gemini 3 Pro, no image generation.

## Gemini in 2026

Gemini 3 Pro has the largest context window of the four at 1 million tokens — enough to load an entire large codebase, a full year of emails, or hundreds of research papers in a single session. It leads on GPQA (graduate-level reasoning) benchmarks.

Its deepest advantage is Google integration: Gemini inside Google Workspace reads your Gmail, Drive documents, and Calendar natively. For users already in the Google ecosystem, this is a meaningful productivity advantage no other model offers.

Gemini Flash is also the cheapest capable model at $0.075 per million input tokens — 33x cheaper than GPT-4o for high-volume API use cases.

**Where it wins**: Longest context window (1M tokens), Google Workspace integration, graduate reasoning, cheapest capable API tier (Flash).

**Where it loses**: Writing quality perceived as slightly less polished than Claude, ecosystem depth behind OpenAI for third-party tools.

## Grok in 2026

Grok 3 is xAI's model, deeply integrated with X (formerly Twitter). Its defining feature is real-time access to X posts, trends, and public conversations — no other major model has this natively. If you are building applications that need live social media data or want AI that understands what is happening right now, Grok is the only option.

Grok 3 Mini's API pricing ($0.30 input / $0.50 output per million tokens) makes it one of the more affordable options for high-volume tasks. The model quality is competitive with GPT-4o on general tasks but trails Claude on coding.

**Where it wins**: Real-time X/social data, lowest-cost API for capable models (Mini tier), reasoning transparency.

**Where it loses**: Smaller ecosystem, coding benchmarks behind Claude, less general adoption than the other three.

## Which Should You Use?

| Task | Best model | Why |
|------|-----------|-----|
| Writing code, fixing bugs | Claude | SWE-Bench 72.7%, best autonomous coding |
| Long-form writing, editing | Claude | Most precise instruction following |
| Research over huge documents | Gemini | 1M token context |
| Google Workspace tasks | Gemini | Native Gmail/Drive access |
| General chat, mixed tasks | ChatGPT | Widest feature set |
| Real-time social/news data | Grok | Only model with live X access |
| Cost-sensitive API (high volume) | Gemini Flash | $0.075/M input tokens |
| On-device / open source alternative | Qwen 3.5 | Apache 2.0, runs locally, competitive benchmarks |

## What Most Developers Actually Do

Use two models: Claude for coding and deep writing tasks, and either ChatGPT or Gemini for general queries and research. The $20/month Claude Pro subscription combined with a free Gemini tier covers 95% of professional use cases for around $20/month total.

For API workloads: Claude Haiku for most tasks, Gemini Flash for the cheapest tier, Claude Sonnet when quality matters.

## Key Takeaways

- **June 2026:** Claude Fable 5 ($10/$50 per million tokens) is the new premium pick for long-horizon agentic coding; Sonnet 4.6 stays the everyday default
- Claude leads on coding (SWE-Bench 72.7%) — the most practical benchmark for developers
- Gemini leads on context window (1M tokens) and Google integration
- ChatGPT leads on ecosystem breadth, user base, and third-party tool support
- Grok is the only model with real-time X/social data access
- Gemini Flash ($0.075/M tokens) is 33x cheaper than GPT-4o for API workloads
- **For developers**: Claude Pro at $20/month is the best single-subscription value for coding and writing. Add Gemini free tier for long-context research tasks.
- **For API builders**: Benchmark your specific task — the best model varies significantly by use case. Don't assume GPT-4o is best by default.