Should I use Grok 4.5 or Claude Sonnet 5 for coding?

For pure coding throughput at lowest cost: Grok 4.5 ($2/$6 per MTok, leads DeepSWE 1.0 62.0%, Terminal-Bench 2.1 83.3%, SWE Marathon 29.0%). For balanced coding + reasoning + long-context work: Claude Sonnet 5 ($2/$10 intro pricing, 1M context, superior code review). Grok 4.5 wins on cost; Sonnet 5 wins on nuance and context window.

Which is cheaper: Grok 4.5 or Claude Sonnet 5?

Grok 4.5 is cheaper on output tokens ($6 vs $10 per MTok). Both cost $2 per MTok input. For a typical 30K-input / 5K-output coding task: Grok 4.5 = $0.09, Sonnet 5 (intro) = $0.11. After August 31, 2026 when Sonnet 5's intro pricing ends and shifts to $3/$15, Grok 4.5 becomes decisively cheaper: $0.09 vs $0.165.

Which has the bigger context window?

Claude Sonnet 5 offers 1M tokens by default with 128K output tokens. Grok 4.5 offers 500K tokens. For document-heavy workflows (long specs, whole-repo context, legal review), Sonnet 5's 1M context is a meaningful advantage — Grok 4.5 hits its limit sooner. For most coding tasks under 500K tokens, both work fine.

Which model works better in Cursor?

Both work in Cursor, but Grok 4.5 has a co-training advantage — it was trained on aggregated Cursor coding traces after SpaceX acquired Cursor in June 2026. This gives Grok 4.5 an edge on Cursor-native patterns (accepted-vs-rejected suggestions, multi-file edits, precise diffs). Claude Sonnet 5 is still an excellent choice, especially for the 1M context window and code review quality — but Grok 4.5 is the co-tuned default in July 2026.

Quick Answer

Grok 4.5 vs Claude Sonnet 5: Which to Use for Coding (July 2026)

Published: July 10, 2026

Two Fresh Models, One Choice

Both launched in the last two weeks of June/July 2026:

Claude Sonnet 5 — Anthropic, June 30, 2026
Grok 4.5 — SpaceXAI, July 8, 2026

They occupy similar price points ($2 input, $6-10 output per MTok) and target similar workloads (coding-heavy production use). For developers picking a default coding model this week, here’s the head-to-head.

Head-to-Head Specs

Feature	Grok 4.5	Claude Sonnet 5
Provider	SpaceXAI	Anthropic
Launched	July 8, 2026	June 30, 2026
Input / MTok	$2.00	$2.00 (intro)
Output / MTok	$6.00	$10.00 (intro), $15 after Aug 31
Context window	500K	1M
Max output	~64K	128K
Serving speed	~80 tok/s	~70-90 tok/s
Native ecosystem	Cursor (co-trained), X, grok.com	Claude Code, Claude Desktop, Projects

Benchmark Comparison

Benchmark	Grok 4.5	Claude Sonnet 5	Winner
DeepSWE 1.0	62.0%	~57%	Grok 4.5
Terminal-Bench 2.1	83.3%	~80%	Grok 4.5
SWE Marathon (pass@1)	29.0%	~27%	Grok 4.5
SWE-bench Pro	~63%	~65%	Sonnet 5
Human-eval multilingual	~68%	~72%	Sonnet 5
MMLU Pro	~86%	~88%	Sonnet 5
HLE (Humanity’s Last Exam)	~48%	~50%	Sonnet 5
MRCR-v2 (long context)	N/A (500K max)	~87%	Sonnet 5

Reading the table: Grok 4.5 leads coding-throughput benchmarks (DeepSWE, Terminal-Bench, SWE Marathon). Sonnet 5 leads on nuance, multilingual coding, reasoning, and long-context recall.

Where Each Wins

Grok 4.5 wins for:

DeepSWE 1.0 / SWE Marathon — the two most-cited “long-horizon coding” benchmarks
Terminal-Bench 2.1 — 83.3% vs Sonnet 5’s ~80%
Cost per task — $6 output token vs Sonnet 5’s $10 (intro) / $15 (post-August)
Cursor-native workflows — co-trained with Cursor coding traces
Speed at $6/MTok — best value on serving throughput

Claude Sonnet 5 wins for:

1M context window — 2x Grok 4.5’s 500K
128K output tokens — for long responses, code files, or reports
Code review — nuanced critique remains Sonnet’s strength
Multilingual coding — better on Kotlin, Rust, Ruby, less-common languages
Extended thinking — mature multi-step reasoning
Claude Code CLI ecosystem — deep Anthropic tooling
AWS Bedrock hosting — available on Bedrock (Grok is not)
Prompt caching — Anthropic’s caching cuts input costs on repeat prompts

Pricing Reality Check

Task: 30K input / 5K output (typical coding task).

Model	Cost / Task	Cost / 10K Tasks
Grok 4.5	$0.09	$900
Sonnet 5 (intro, through Aug 31)	$0.11	$1,100
Sonnet 5 (standard, from Sep 1)	$0.165	$1,650

Sonnet 5 intro pricing ends August 31, 2026 and shifts to $3/$15. At that point Grok 4.5 is decisively cheaper for the same output — worth planning your Q4 budget around.

For long-context tasks (200K input / 2K output):

Model	Cost / Task	Cost / 10K Tasks
Grok 4.5	$0.412	$4,120
Sonnet 5 (intro)	$0.42	$4,200

At high input volume the two are effectively tied — but Sonnet 5 supports 1M input while Grok caps at 500K.

Ecosystem Differences

Feature	Grok 4.5	Sonnet 5
First-party CLI	❌	Claude Code
IDE co-tuning	Cursor (native)	Claude Code, Projects
Bedrock	❌	✅
Azure AI Foundry	❌	✅
Vertex AI	❌	✅
MCP support	✅	✅
Extended thinking	⚠️ Limited	✅ Mature
Prompt caching	⚠️ Basic	✅ Advanced
Artifacts	❌	✅ (Claude Desktop)

If you’re already deep in the Anthropic ecosystem (Claude Code, Projects, Bedrock), the migration cost to Grok 4.5 is real. If you’re starting fresh, Grok 4.5’s ecosystem is smaller but the API compatibility with OpenAI SDK is simple.

Decision Framework

What matters most?
│
├── Cheapest capable coding model
│   → Grok 4.5 ($6 output)
│
├── Balanced coding + reasoning + writing
│   → Sonnet 5
│
├── Long context (>500K tokens)
│   → Sonnet 5 (1M context)
│
├── Long output (>64K tokens)
│   → Sonnet 5 (128K output)
│
├── Code review quality
│   → Sonnet 5
│
├── Cursor-native workflow
│   → Grok 4.5 (co-trained)
│
├── Claude Code CLI workflow
│   → Sonnet 5 (native)
│
├── AWS Bedrock hosting requirement
│   → Sonnet 5
│
├── Highest raw SWE benchmarks
│   → Grok 4.5 (leads DeepSWE, SWE Marathon)
│
└── Multilingual (Kotlin, Ruby, Rust)
    → Sonnet 5

Practical Two-Model Setup

Many teams route between both:

Task type → Model
├── Code generation, refactor → Grok 4.5 (cost)
├── Code review, PR triage → Sonnet 5 (nuance)
├── Long-context repo Q&A → Sonnet 5 (1M window)
├── Extended debug session → Sonnet 5 (extended thinking)
├── Batch high-volume coding → Grok 4.5 (speed + cost)
├── Multilingual codebases → Sonnet 5 (Kotlin, Rust)
└── Writing / docs / analysis → Sonnet 5 (nuance)

Route via LiteLLM, Portkey, or your own dispatcher. This captures cost savings on coding while preserving quality on review and analysis.

What Changed in Late June / Early July 2026

June 30, 2026: Claude Sonnet 5 launched at $2/$10 intro pricing, 1M context, 128K output
July 8, 2026: Grok 4.5 launched at $2/$6, 500K context, co-trained with Cursor data
August 31, 2026: Sonnet 5 intro pricing ends → shifts to $3/$15

The Bottom Line

For new coding projects in July 2026: Grok 4.5 is the default recommendation on price and coding-benchmark performance.

For teams already on Anthropic: Stay on Sonnet 5 for its 1M context, Claude Code ecosystem, and code-review quality. Add Grok 4.5 as the cost-optimized second model for high-volume tasks.

For long-context and analytical work: Sonnet 5 is uniquely capable — Grok 4.5 can’t match the 1M window.

Sources

Claude Sonnet 5 (Anthropic) — official model page
Grok 4.5 Launch (SpaceXAI) — launch details
Anthropic API Pricing — Sonnet 5 pricing tiers
xAI API Docs — Grok 4.5 API reference