Last Updated: June 2, 2026 — All data sourced from verified reports. See Sources section.
The 2026 AI model race is closer than you think. GPT-5.5 leads on some benchmarks, Claude Opus 4.7 dominates others, and Gemini 3.1 Pro is the cheapest by far. Here’s the data.
Pricing: What You Actually Pay
| Model | Input (per 1M tokens) | Output (per 1M tokens) | Context Window |
|---|---|---|---|
| GPT-5.5 | $5.00 | $30.00 | 1M |
| GPT-5.5 Pro | $30.00 | $180.00 | 1M |
| Claude Opus 4.7 | $15.00 | $75.00 | 1M |
| Gemini 3.1 Pro | $2.50 | $15.00 | 2M |
(Sources: Codersera, Tech Insider)
Key takeaway: GPT-5.5 undercuts Claude Opus 4.7 by 3x on input tokens. Gemini 3.1 Pro is the cheapest at $2.50/$15 — 6x cheaper than Claude.
Cached input: GPT-5.5 offers a 90% discount on cached input tokens ($0.50 per 1M), making repeated queries extremely cost-effective.
Benchmark Performance
Where GPT-5.5 Leads
| Benchmark | GPT-5.5 | Claude Opus 4.7 | Source |
|---|---|---|---|
| Terminal-Bench 2.0 | 82.7% | — | Tech Insider |
| SWE-bench Verified | 88.7% | — | Codersera |
| MMLU | 92.4% | — | Codersera |
| GDPval | 84.9% | — | Tech Insider |
| MMMU-Pro | 76.0% | — | Codersera |
Where Claude Opus 4.7 Leads
| Benchmark | Claude Opus 4.7 | GPT-5.5 | Source |
|---|---|---|---|
| SWE-Bench Pro | 64.3% | 58.6% | Tech Insider |
| Long-form Factuality | 64% hallucination rate | 86% hallucination rate | Codersera |
The Hallucination Problem
This is the most important finding:
- GPT-5.5 Instant reduced hallucinations by 52.5% on high-stakes prompts (medical, legal, financial) — from 18.7% to 8.9% on OpenAI’s internal HallucinationBench (Source: Codersera)
- However, on long-form factuality benchmarks without tool use, GPT-5.5 still hallucinates at roughly 86%, compared to Claude Opus 4.7’s 36% (Source: Codersera)
What this means: GPT-5.5’s hallucination improvement comes largely from tool grounding and context engineering, not from the base model itself. For applications where accuracy matters more than speed, Claude Opus 4.7 is still more reliable.
Model Variants
OpenAI shipped three variants of GPT-5.5 on April 23, 2026 (Source: Codersera):
| Variant | Purpose | Availability |
|---|---|---|
| GPT-5.5 | Standard reasoning | API + ChatGPT |
| GPT-5.5 Instant | Fast, low-hallucination | ChatGPT default |
| GPT-5.5 Pro | Deep reasoning, long-horizon tasks | ChatGPT Pro/Enterprise + API |
| GPT-5.5 Thinking | Extended chain-of-thought | API |
GPT-5.5 Instant replaced GPT-5.3 as ChatGPT’s default model. GPT-5.3 remains available for 3 months for migration.
Agentic Capabilities
Codex CLI
OpenAI’s Codex CLI evolved into a persistent autonomous agent runtime in May 2026. Key features (Source: Codersera):
- Goal Mode — Set objectives, Codex works autonomously for hours
- Conversation search — Search across local conversation history
- MCP support — Per-server environment targeting and OAuth on streamable HTTP servers
- Read-only MCP tools — Run concurrently for parallel speedups
Claude Code
Anthropic’s terminal-based coding agent with Claude Opus 4.7 remains the best for code quality. It reads, writes, searches, and executes code directly in your terminal.
Gemini 3.1 Pro
Google’s agent framework integrates deeply with Workspace (Docs, Sheets, Gmail) and offers the largest context window at 2M tokens.
ChatGPT for Excel and Google Sheets
Launched May 5, 2026, with GPT-5.5 in the model picker (Source: Codersera):
- Handles trackers, budgets, formulas, multi-tab files, scenario analysis, data cleanup
- Skills — Reusable playbooks for specific spreadsheet workflows
- Apps — Connect to outside data sources (financial integrations, internal databases)
- Available to Free, Go, Plus, Pro, Business, Enterprise, Edu, and K-12
Which Should You Choose?
Choose GPT-5.5 if:
- You want the best price-to-performance ratio ($5/$30)
- You need autonomous agent capabilities (Codex CLI)
- You work in the OpenAI ecosystem (ChatGPT, DALL-E, plugins)
Choose Claude Opus 4.7 if:
- Accuracy matters more than cost (36% vs 86% hallucination rate on long-form)
- You need the best code quality (64.3% SWE-Bench Pro)
- You write long-form content
Choose Gemini 3.1 Pro if:
- You need the cheapest API ($2.50/$15)
- You need the largest context window (2M tokens)
- You’re in the Google Workspace ecosystem
Sources
- Codersera — OpenAI May 2026 Updates: GPT-5.5 Instant, Codex, GPT-5.6 — Published May 28, 2026
- Tech Insider — GPT-5.5 Launch: 82.7% Terminal-Bench, $5 API — Published May 26, 2026
- Knightli — Google I/O 2026 Summary: Gemini 3.5, Omni, Antigravity — Published May 21, 2026
This article is updated monthly. Last verified: June 2, 2026. Found an error? Contact us.