Grok 4.5 is xAI's coding-focused large language model, launched on July 8, 2026. It ships a 500K-token context window and an OpenAI-compatible API priced at $2 per million input tokens and $6 per million output tokens — roughly a third of the price of top-tier models. Its standout claim is token efficiency: xAI reports Grok 4.5 resolves software-engineering tasks using about 4x fewer output tokens than Claude Opus 4.8, which can make it dramatically cheaper to run in real coding agents.
The pitch is simple: an Opus-class model that is faster, more token-efficient, and lower cost. xAI trained it partly on real developer session data from the Cursor editor and benchmarked it on tasks designed to measure what an AI can actually do inside a real codebase over a long session — not just one-shot puzzles. That focus on agentic, in-editor coding is what separates Grok 4.5 from a general-purpose chat model.
This guide covers Grok 4.5's benchmarks, pricing, context window, and how it stacks up against the frontier — plus the one number that matters most for anyone paying per token.
Key Takeaways
- Grok 4.5 launched July 8, 2026, with a 500K-token context window and an OpenAI-compatible API.
- Pricing is $2/$6 per million input/output tokens — well below Opus- and GPT-tier flagships.
- It scores 54 on the Artificial Analysis Intelligence Index (fourth place), behind Fable 5, GPT-5.5, and Opus 4.8.
- xAI reports 83.3% on Terminal-Bench 2.1 and a 64.7% resolve rate on SWE-Bench Pro.
- Token efficiency is the headline: ~15,954 output tokens per SWE-Bench Pro task vs ~67,020 for Opus 4.8 (a 4.2x gap).
What is Grok 4.5?
Grok 4.5 is xAI's latest model in the Grok line, tuned specifically for real-world software engineering and agentic coding. It exposes an OpenAI-compatible API, so teams already using OpenAI's SDK can point it at Grok with minimal code changes, and it supports configurable reasoning effort so you can trade speed for depth per request.
What makes it different is the training data. xAI trained Grok 4.5 partly on real Cursor developer sessions and evaluated it on benchmarks built to measure sustained performance inside a live codebase. That is a deliberate bet: most coding benchmarks reward one-shot correctness, but real engineering is a long session of reading files, editing, running tests, and iterating. For the wider field, our roundup of the best AI coding assistants in 2026 shows where Grok fits.
How good are Grok 4.5's benchmarks?
Grok 4.5's benchmarks are strong on coding but mid-pack on general intelligence: it posts 83.3% on Terminal-Bench 2.1 and a 64.7% resolve rate on SWE-Bench Pro, while landing fourth on the broad Artificial Analysis Intelligence Index with a score of 54. In other words, it punches above its price on coding tasks but isn't the outright smartest model available.
| Benchmark | What it measures | Grok 4.5 result |
|---|---|---|
| Artificial Analysis Index | General intelligence | 54 (4th, behind Fable 5, GPT-5.5, Opus 4.8) |
| Terminal-Bench 2.1 | Command-line / agentic coding | 83.3% (xAI-reported) |
| SWE-Bench Pro | Real bug-fix resolve rate | 64.7% (xAI-reported) |
| SWE-Bench Multilingual | Cross-language coding | 78.0% (Cursor-reported) |
The pattern is consistent: Grok 4.5 is a specialist. On the general index it sits behind the flagships, but on coding-specific and agentic benchmarks it is genuinely competitive with models that cost several times more. According to Artificial Analysis, that 54 index score places it fourth overall — respectable, not dominant.
As always with launch numbers, note that Terminal-Bench and SWE-Bench Pro figures are xAI-reported, while the SWE-Bench Multilingual result comes from Cursor's independent testing. Cross-vendor confirmation on the multilingual benchmark is a good sign that the coding strength is real and not just favorable framing.
Grok 4.5 pricing and token efficiency
Grok 4.5's real advantage is cost, and it comes from two places: a low per-token price ($2/$6 per million) and exceptional token efficiency. On SWE-Bench Pro, xAI reports Grok 4.5 resolves an average task using 15,954 output tokens, against 67,020 for Opus 4.8 at maximum settings — a 4.2x gap that multiplies the sticker-price savings.
| Model | Input $/1M | Output $/1M | Avg output tokens (SWE-Bench Pro) |
|---|---|---|---|
| Grok 4.5 | $2 | $6 | ~15,954 |
| Claude Opus 4.8 (max) | $5 | $25 | ~67,020 |
Stack those two factors and the difference is large. Grok 4.5's output tokens are cheaper per token and it uses roughly a quarter as many per task. For a coding agent running thousands of tasks a day, that compounds into a very different monthly bill. This is the core of xAI's pitch: not "the smartest model," but "the most cost-effective way to get Opus-class coding results at scale."
The trade-off is that token efficiency can correlate with less exhaustive exploration. On the hardest, most ambiguous tasks, a model that thinks longer sometimes lands a fix a terser model misses. Benchmark that on your own workload before assuming the cost savings are free.
Is Grok 4.5 better than Claude and GPT-5.6?
Grok 4.5 is not the smartest model overall — it sits behind Opus 4.8, GPT-5.5, and Fable 5 on general intelligence — but it may be the most economical for high-volume coding, thanks to its 4x token-efficiency edge and low price. The right choice depends on whether you optimize for peak capability or cost per solved task.
- vs Claude Opus 5: Anthropic's new flagship, covered in our Claude Opus 5 explainer, leads on raw capability and alignment. Grok 4.5 wins on price and token efficiency. Choose Opus 5 for the hardest problems, Grok 4.5 for cost-sensitive volume.
- vs GPT-5.6: OpenAI's GPT-5.6 family is stronger on general reasoning. Grok's OpenAI-compatible API makes A/B testing the two cheap to set up.
- vs Kimi K3: For open-weight cost optimization, Moonshot's Kimi K3 is the other value play. Grok 4.5 is closed but tuned on real editor data.
If you already run tooling like Cursor, Copilot, or Windsurf, Grok 4.5 is easy to slot in as a cheaper backend and measure directly against your current model.
Who should use Grok 4.5?
Grok 4.5 is the right pick for teams running high-volume, cost-sensitive coding workloads where the per-task bill matters more than squeezing out the last few points of capability. Its token efficiency and low price make it especially attractive for autonomous agents that run continuously.
- Coding agents at scale — the 4x token efficiency directly cuts your largest cost line.
- Teams on OpenAI's SDK — the compatible API means near-zero migration friction to test it.
- Latency-sensitive tools — configurable reasoning effort lets you dial down thinking for fast responses.
- Budget-constrained startups — Opus-class coding at roughly a third of the price is a real edge.
Who should skip it: teams tackling the hardest, most open-ended problems where peak intelligence wins, and anyone who needs the very top of the general-reasoning leaderboard. For those, a flagship like Opus 5 or GPT-5.6 remains the better tool.
Frequently asked questions
When was Grok 4.5 released? Grok 4.5 was released by xAI on July 8, 2026. It launched with an OpenAI-compatible API and was quickly made available in coding tools including Cursor.
How much does Grok 4.5 cost? Grok 4.5 costs $2 per million input tokens and $6 per million output tokens. Combined with its high token efficiency, that makes it one of the cheapest ways to run frontier-class coding tasks.
What is Grok 4.5's context window? Grok 4.5 has a 500K-token context window, large enough to hold substantial codebases and long agentic sessions, though smaller than the 1M-token windows of some rivals.
Is Grok 4.5 good at coding? Yes. Grok 4.5 scores 83.3% on Terminal-Bench 2.1 and 64.7% on SWE-Bench Pro, and was trained partly on real Cursor developer sessions, making it genuinely strong at agentic, in-editor coding.
How does Grok 4.5 compare to Claude Opus 4.8? Opus 4.8 is stronger on general intelligence, but Grok 4.5 resolves SWE-Bench Pro tasks with about 4x fewer output tokens (15,954 vs 67,020) at a lower per-token price, making it far cheaper per task.
Does Grok 4.5 have an OpenAI-compatible API? Yes. Grok 4.5 exposes an OpenAI-compatible API, so teams already using OpenAI's SDK can switch or A/B test with minimal code changes.
The verdict
Grok 4.5 is not trying to be the smartest model — it's trying to be the most cost-effective coding model, and on that goal it delivers. A 4.2x token-efficiency edge over Opus 4.8, a low $2/$6 price, an OpenAI-compatible API, and training on real editor sessions add up to a compelling value play for teams that run a lot of code through a model every day.
Our recommendation: if you operate a coding agent at scale or watch your token bill closely, put Grok 4.5 in an A/B test against your current backend this week — the switching cost is near zero and the potential savings are large. If you're chasing peak capability on the hardest problems, stick with a flagship like Claude Opus 5. For most teams, the smart move is to run both and route by task difficulty.