Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Grok 4.3 for video understanding from native video input or generating pdf, pptx, and xlsx files directly. On a tight budget at scale, Grok 4.3 is the value pick.
Claude Sonnet 4.5 (Anthropic) and Grok 4.3 (xAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Grok 4.3 is the current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences
Price: Grok 4.3 is about 2.4× cheaper on input ($1.25/$2.5 per 1M tokens vs $3/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
Context window: Grok 4.3 holds 5× more — 1M (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Grok 4.3 is the newer model by about 7 months (released April 30, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Sonnet 4.5
Grok 4.3
Provider
Anthropic (US)
xAI (US)
Released
September 29, 2025
April 30, 2026
Context window
200K (~300 pages)
1M (~1,500 pages)
Price (in/out)
$3/$15 per 1M tokens
$1.25/$2.5 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, video, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — Grok 4.3 is comparatively weak here — less independent benchmark coverage than OpenAI, Anthropic, or Google
Computer use and GUI automation (61.4% OSWorld at launch): Claude Sonnet 4.5 — Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Grok 4.3 does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks: Claude Sonnet 4.5 — Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Grok 4.3 does not.
Video understanding from native video input: Grok 4.3 — The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it runs cheaper at $1.25/$2.5 per 1M tokens.
Generating PDF, PPTX, and XLSX files directly: Grok 4.3 — The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it carries the larger 1M context.
Real-time questions using live X data: Grok 4.3 — The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it is the newer of the two.
Lowest cost at scale: Grok 4.3 — At $1.25/$2.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input: Grok 4.3 — Its 1M window is about 5× larger than Claude Sonnet 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Grok 4.3 — At $1.25/$2.5 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Grok 4.3 — Larger 1M window fits more in one prompt.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — It is specifically built for that.
Anyone whose priority is video understanding from native video input: Grok 4.3 — That is its strongest area.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
Grok 4.3: where it fits
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Released April 30, 2026 by xAI, it is built for video understanding from native video input, generating PDF, PPTX, and XLSX files directly, real-time questions using live X data, and long-context, multi-agent reasoning.
Its trade-offs: higher context pricing on requests above 200K tokens, and less independent benchmark coverage than OpenAI, Anthropic, or Google. At $1.25 in / $2.5 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Sonnet 4.5 and Grok 4.3 overlap enough that the right pick depends on your specific job. Grok 4.3 costs less per token; Grok 4.3 holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, Grok 4.3 for video understanding from native video input. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Sonnet 4.5 or Grok 4.3 better for coding?
Public SWE-Bench figures are not available for Grok 4.3, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch while Grok 4.3 leans toward video understanding from native video input, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 4.5 or Grok 4.3?
Grok 4.3 is cheaper — $3/$15 per 1M tokens vs $1.25/$2.5 per 1M tokens, roughly 2.4× apart on input.
Which has the bigger context window?
Grok 4.3 — 1M vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Grok 4.3 together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Grok 4.3 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 4.5 or Grok 4.3?
Grok 4.3 — released April 30, 2026, about 7 months after Claude Sonnet 4.5.
Claude Sonnet 4.5 vs Grok 4.3
Anthropic · US | xAI · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Grok 4.3 for video understanding from native video input or generating pdf, pptx, and xlsx files directly. On a tight budget at scale, Grok 4.3 is the value pick.
Claude Sonnet 4.5 (Anthropic) and Grok 4.3 (xAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Grok 4.3 is the current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
▸Price: Grok 4.3 is about 2.4× cheaper on input ($1.25/$2.5 per 1M tokens vs $3/$15 per 1M tokens) — meaningful once you are processing millions of tokens a month.
▸Context window: Grok 4.3 holds 5× more — 1M (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Grok 4.3 is the newer model by about 7 months (released April 30, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Sonnet 4.5
Grok 4.3
Provider
Anthropic (US)
xAI (US)
Released
September 29, 2025
April 30, 2026
Context window
200K (~300 pages)
1M (~1,500 pages)
Price (in/out)
$3/$15 per 1M tokens
$1.25/$2.5 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, video, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch
Claude Sonnet 4.5
Grok 4.3 is comparatively weak here — less independent benchmark coverage than OpenAI, Anthropic, or Google
Computer use and GUI automation (61.4% OSWorld at launch)
Claude Sonnet 4.5
Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Grok 4.3 does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks
Claude Sonnet 4.5
Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks among its strengths; Grok 4.3 does not.
Video understanding from native video input
Grok 4.3
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it runs cheaper at $1.25/$2.5 per 1M tokens.
Generating PDF, PPTX, and XLSX files directly
Grok 4.3
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it carries the larger 1M context.
Real-time questions using live X data
Grok 4.3
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it is the newer of the two.
Lowest cost at scale
Grok 4.3
At $1.25/$2.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Grok 4.3
Its 1M window is about 5× larger than Claude Sonnet 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Grok 4.3
At $1.25/$2.5 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Grok 4.3
Larger 1M window fits more in one prompt.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch
→ Claude Sonnet 4.5
It is specifically built for that.
Anyone whose priority is video understanding from native video input
→ Grok 4.3
That is its strongest area.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
Grok 4.3: where it fits
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Released April 30, 2026 by xAI, it is built for video understanding from native video input, generating PDF, PPTX, and XLSX files directly, real-time questions using live X data, and long-context, multi-agent reasoning.
Its trade-offs: higher context pricing on requests above 200K tokens, and less independent benchmark coverage than OpenAI, Anthropic, or Google. At $1.25 in / $2.5 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Claude Sonnet 4.5 and Grok 4.3 overlap enough that the right pick depends on your specific job. Grok 4.3 costs less per token; Grok 4.3 holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, Grok 4.3 for video understanding from native video input. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 4.5 and Grok 4.3 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
Is Claude Sonnet 4.5 or Grok 4.3 better for coding?
Public SWE-Bench figures are not available for Grok 4.3, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch while Grok 4.3 leans toward video understanding from native video input, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 4.5 or Grok 4.3?
Grok 4.3 is cheaper — $3/$15 per 1M tokens vs $1.25/$2.5 per 1M tokens, roughly 2.4× apart on input.
Which has the bigger context window?
Grok 4.3 — 1M vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Grok 4.3 together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Grok 4.3 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 4.5 or Grok 4.3?
Grok 4.3 — released April 30, 2026, about 7 months after Claude Sonnet 4.5.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.