Pick GPT-5.5 for terminal, cli and computer-use automation or long-horizon tool sequencing. Pick Grok 4 for 2m production context window or real-time data via x integration. On a tight budget at scale, Grok 4 is the value pick.
GPT-5.5 (OpenAI) and Grok 4 (xAI) are two of the models people most often weigh against each other in 2026. GPT-5.5 is openAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Grok 4 is xAI's 2M-context model with live data access and strong reasoning chops. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences
Price: Grok 4 is about 1.7× cheaper on input ($3/$15 per 1M tokens vs $5/$30 per 1M tokens) — modest, but it adds up at steady volume.
Context window: Grok 4 holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: GPT-5.5 is the newer model by about 10 months (released April 23, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
GPT-5.5
Grok 4
Provider
OpenAI (US)
xAI (US)
Released
April 23, 2026
2025
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$5/$30 per 1M tokens
$3/$15 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Terminal, CLI and computer-use automation: GPT-5.5 — A core design strength of GPT-5.5.
Long-horizon tool sequencing: GPT-5.5 — A core design strength of GPT-5.5.
Natively omnimodal input: GPT-5.5 — A core design strength of GPT-5.5.
2M production context window: Grok 4 — A core design strength of Grok 4.
Real-time data via X integration: Grok 4 — A core design strength of Grok 4.
Strong academic reasoning: Grok 4 — A core design strength of Grok 4.
Lowest cost at scale: Grok 4 — At $3/$15 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 — Its 2M window is about 2× larger, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Grok 4 — At $3/$15 per 1M tokens it undercuts GPT-5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Grok 4 — Larger 2M window fits more in one prompt.
Anyone whose priority is terminal, cli and computer-use automation: GPT-5.5 — It is specifically built for that.
Anyone whose priority is 2m production context window: Grok 4 — That is its strongest area.
GPT-5.5: where it fits
OpenAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Released April 23, 2026 by OpenAI, it is built for terminal, CLI and computer-use automation, long-horizon tool sequencing, natively omnimodal input, and browser-driving agents.
Its trade-offs are real: trails Opus 4.8 on hardest coding benchmarks, and tiered long-context pricing above 272K tokens. At $5 in / $30 out per million tokens, it sits in the premium price band.
Grok 4: where it fits
XAI's 2M-context model with live data access and strong reasoning chops. Released 2025 by xAI, it is built for 2M production context window, real-time data via X integration, strong academic reasoning, and no long-context surcharge.
Its trade-offs: smaller ecosystem than OpenAI/Google, and less independent benchmark coverage. At $3 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
GPT-5.5 and Grok 4 overlap enough that the right pick depends on your specific job. Grok 4 costs less per token; Grok 4 holds the larger context; and each leads in its own area — GPT-5.5 for terminal, cli and computer-use automation, Grok 4 for 2m production context window. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is GPT-5.5 or Grok 4 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, GPT-5.5 leans toward terminal, cli and computer-use automation while Grok 4 leans toward 2m production context window, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, GPT-5.5 or Grok 4?
Grok 4 is cheaper — $5/$30 per 1M tokens vs $3/$15 per 1M tokens, roughly 1.7× apart on input.
Which has the bigger context window?
Grok 4 — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both GPT-5.5 and Grok 4 together?
Yes — a multi-model platform like LumiChats gives you GPT-5.5, Grok 4 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, GPT-5.5 or Grok 4?
GPT-5.5 — released April 23, 2026, about 10 months after Grok 4.
GPT-5.5 vs Grok 4
OpenAI · US | xAI · US · Updated June 2026
Quick verdict
Pick GPT-5.5 for terminal, cli and computer-use automation or long-horizon tool sequencing. Pick Grok 4 for 2m production context window or real-time data via x integration. On a tight budget at scale, Grok 4 is the value pick.
GPT-5.5 (OpenAI) and Grok 4 (xAI) are two of the models people most often weigh against each other in 2026. GPT-5.5 is openAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Grok 4 is xAI's 2M-context model with live data access and strong reasoning chops. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
▸Price: Grok 4 is about 1.7× cheaper on input ($3/$15 per 1M tokens vs $5/$30 per 1M tokens) — modest, but it adds up at steady volume.
▸Context window: Grok 4 holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: GPT-5.5 is the newer model by about 10 months (released April 23, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
GPT-5.5
Grok 4
Provider
OpenAI (US)
xAI (US)
Released
April 23, 2026
2025
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$5/$30 per 1M tokens
$3/$15 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, audio, video, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Terminal, CLI and computer-use automation
GPT-5.5
A core design strength of GPT-5.5.
Long-horizon tool sequencing
GPT-5.5
A core design strength of GPT-5.5.
Natively omnimodal input
GPT-5.5
A core design strength of GPT-5.5.
2M production context window
Grok 4
A core design strength of Grok 4.
Real-time data via X integration
Grok 4
A core design strength of Grok 4.
Strong academic reasoning
Grok 4
A core design strength of Grok 4.
Lowest cost at scale
Grok 4
At $3/$15 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
Its 2M window is about 2× larger, fitting roughly 3,000 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Grok 4
At $3/$15 per 1M tokens it undercuts GPT-5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Grok 4
Larger 2M window fits more in one prompt.
Anyone whose priority is terminal, cli and computer-use automation
→ GPT-5.5
It is specifically built for that.
Anyone whose priority is 2m production context window
→ Grok 4
That is its strongest area.
GPT-5.5: where it fits
OpenAI's first fully retrained base since GPT-4.5 — the terminal and computer-use champion. Released April 23, 2026 by OpenAI, it is built for terminal, CLI and computer-use automation, long-horizon tool sequencing, natively omnimodal input, and browser-driving agents.
Its trade-offs are real: trails Opus 4.8 on hardest coding benchmarks, and tiered long-context pricing above 272K tokens. At $5 in / $30 out per million tokens, it sits in the premium price band.
Grok 4: where it fits
XAI's 2M-context model with live data access and strong reasoning chops. Released 2025 by xAI, it is built for 2M production context window, real-time data via X integration, strong academic reasoning, and no long-context surcharge.
Its trade-offs: smaller ecosystem than OpenAI/Google, and less independent benchmark coverage. At $3 in / $15 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
GPT-5.5 and Grok 4 overlap enough that the right pick depends on your specific job. Grok 4 costs less per token; Grok 4 holds the larger context; and each leads in its own area — GPT-5.5 for terminal, cli and computer-use automation, Grok 4 for 2m production context window. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both GPT-5.5 and Grok 4 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.
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, GPT-5.5 leans toward terminal, cli and computer-use automation while Grok 4 leans toward 2m production context window, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, GPT-5.5 or Grok 4?
Grok 4 is cheaper — $5/$30 per 1M tokens vs $3/$15 per 1M tokens, roughly 1.7× apart on input.
Which has the bigger context window?
Grok 4 — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both GPT-5.5 and Grok 4 together?
Yes — a multi-model platform like LumiChats gives you GPT-5.5, Grok 4 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, GPT-5.5 or Grok 4?
GPT-5.5 — released April 23, 2026, about 10 months after Grok 4.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.