Both are xAI models. Grok 4.5 is the newer, generally stronger default; reach for Grok 4 when a specific cost or latency profile matters more than the latest capabilities.
Grok 4 and Grok 4.5 are both xAI models, so the real question is not which lab to trust but which tier fits your workload and budget. Grok 4 is xAI's 2M-context model with live data access and strong reasoning chops. Grok 4.5 is xAI's first coding-focused model — pitched as Opus-class but faster, more token-efficient, and cheaper, undercutting GPT-5.5-Codex. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences
Price: Grok 4.5 is about 1.5× cheaper on input ($2/$6 per 1M tokens vs $3/$15 per 1M tokens) — modest, but it adds up at steady volume.
Context window: Grok 4.5 holds 2× more — 500K (~750 pages) vs 256K (~384 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 4.5 is the newer model by about 12 months (released July 8, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Grok 4
Grok 4.5
Provider
xAI (US)
xAI (US)
Released
July 9, 2025
July 8, 2026
Context window
256K (~384 pages)
500K (~750 pages)
Price (in/out)
$3/$15 per 1M tokens
$2/$6 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
256K context with native tool use: 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.
Cheap, token-efficient agentic coding — about GPT-5.5-Codex quality at roughly half the cost: Grok 4.5 — A core design strength of Grok 4.5.
Extreme token efficiency — around 4x fewer output tokens per task than Opus 4.8: Grok 4.5 — A core design strength of Grok 4.5.
In-IDE coding, trained on real Cursor developer sessions and shipped natively in Cursor: Grok 4.5 — A core design strength of Grok 4.5.
Lowest cost at scale: Grok 4.5 — At $2/$6 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input: Grok 4.5 — Its 500K window is about 2× larger, fitting roughly 750 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Grok 4.5 — At $2/$6 per 1M tokens it undercuts Grok 4, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Grok 4.5 — Larger 500K window fits more in one prompt.
Anyone whose priority is 256k context with native tool use: Grok 4 — It is specifically built for that.
Anyone whose priority is cheap, token-efficient agentic coding — about gpt-5.5-codex quality at roughly half the cost: Grok 4.5 — That is its strongest area.
Grok 4: where it fits
XAI's 2M-context model with live data access and strong reasoning chops. Released July 9, 2025 by xAI, it is built for 256K context with native tool use, real-time data via X integration, strong academic reasoning, and no long-context surcharge.
Its trade-offs are real: 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.
Grok 4.5: where it fits
XAI's first coding-focused model — pitched as Opus-class but faster, more token-efficient, and cheaper, undercutting GPT-5.5-Codex. Released July 8, 2026 by xAI, it is built for cheap, token-efficient agentic coding — about GPT-5.5-Codex quality at roughly half the cost, extreme token efficiency — around 4x fewer output tokens per task than Opus 4.8, in-IDE coding, trained on real Cursor developer sessions and shipped natively in Cursor, and top-tier placement on the Artificial Analysis Intelligence Index.
Its trade-offs: smaller 500K context (halved from the 1M generation), with pricing that doubles above 200K tokens, and eU launch delayed; no open weights. At $2 in / $6 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Grok 4 and Grok 4.5 come from the same lab (xAI), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Grok 4.5 is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Grok 4.5 and drop down only with a concrete reason.
Frequently asked questions
Is Grok 4 or Grok 4.5 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, Grok 4 leans toward 256k context with native tool use while Grok 4.5 leans toward cheap, token-efficient agentic coding — about gpt-5.5-codex quality at roughly half the cost, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Grok 4 or Grok 4.5?
Grok 4.5 is cheaper — $3/$15 per 1M tokens vs $2/$6 per 1M tokens, roughly 1.5× apart on input.
Which has the bigger context window?
Grok 4.5 — 500K vs 256K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Grok 4 to Grok 4.5?
Since both are xAI models, the newer one (Grok 4.5) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Grok 4 or Grok 4.5?
Grok 4.5 — released July 8, 2026, about 12 months after Grok 4.
Grok 4 vs Grok 4.5
xAI · US | xAI · US · Updated June 2026
Quick verdict
Both are xAI models. Grok 4.5 is the newer, generally stronger default; reach for Grok 4 when a specific cost or latency profile matters more than the latest capabilities.
Grok 4 and Grok 4.5 are both xAI models, so the real question is not which lab to trust but which tier fits your workload and budget. Grok 4 is xAI's 2M-context model with live data access and strong reasoning chops. Grok 4.5 is xAI's first coding-focused model — pitched as Opus-class but faster, more token-efficient, and cheaper, undercutting GPT-5.5-Codex. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
▸Price: Grok 4.5 is about 1.5× cheaper on input ($2/$6 per 1M tokens vs $3/$15 per 1M tokens) — modest, but it adds up at steady volume.
▸Context window: Grok 4.5 holds 2× more — 500K (~750 pages) vs 256K (~384 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 4.5 is the newer model by about 12 months (released July 8, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Grok 4
Grok 4.5
Provider
xAI (US)
xAI (US)
Released
July 9, 2025
July 8, 2026
Context window
256K (~384 pages)
500K (~750 pages)
Price (in/out)
$3/$15 per 1M tokens
$2/$6 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
256K context with native tool use
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.
Cheap, token-efficient agentic coding — about GPT-5.5-Codex quality at roughly half the cost
Grok 4.5
A core design strength of Grok 4.5.
Extreme token efficiency — around 4x fewer output tokens per task than Opus 4.8
Grok 4.5
A core design strength of Grok 4.5.
In-IDE coding, trained on real Cursor developer sessions and shipped natively in Cursor
Grok 4.5
A core design strength of Grok 4.5.
Lowest cost at scale
Grok 4.5
At $2/$6 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Grok 4.5
Its 500K window is about 2× larger, fitting roughly 750 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Grok 4.5
At $2/$6 per 1M tokens it undercuts Grok 4, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Grok 4.5
Larger 500K window fits more in one prompt.
Anyone whose priority is 256k context with native tool use
→ Grok 4
It is specifically built for that.
Anyone whose priority is cheap, token-efficient agentic coding — about gpt-5.5-codex quality at roughly half the cost
→ Grok 4.5
That is its strongest area.
Grok 4: where it fits
XAI's 2M-context model with live data access and strong reasoning chops. Released July 9, 2025 by xAI, it is built for 256K context with native tool use, real-time data via X integration, strong academic reasoning, and no long-context surcharge.
Its trade-offs are real: 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.
Grok 4.5: where it fits
XAI's first coding-focused model — pitched as Opus-class but faster, more token-efficient, and cheaper, undercutting GPT-5.5-Codex. Released July 8, 2026 by xAI, it is built for cheap, token-efficient agentic coding — about GPT-5.5-Codex quality at roughly half the cost, extreme token efficiency — around 4x fewer output tokens per task than Opus 4.8, in-IDE coding, trained on real Cursor developer sessions and shipped natively in Cursor, and top-tier placement on the Artificial Analysis Intelligence Index.
Its trade-offs: smaller 500K context (halved from the 1M generation), with pricing that doubles above 200K tokens, and eU launch delayed; no open weights. At $2 in / $6 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Grok 4 and Grok 4.5 come from the same lab (xAI), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Grok 4.5 is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Grok 4.5 and drop down only with a concrete reason.
Want both Grok 4 and Grok 4.5 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, Grok 4 leans toward 256k context with native tool use while Grok 4.5 leans toward cheap, token-efficient agentic coding — about gpt-5.5-codex quality at roughly half the cost, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Grok 4 or Grok 4.5?
Grok 4.5 is cheaper — $3/$15 per 1M tokens vs $2/$6 per 1M tokens, roughly 1.5× apart on input.
Which has the bigger context window?
Grok 4.5 — 500K vs 256K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Grok 4 to Grok 4.5?
Since both are xAI models, the newer one (Grok 4.5) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Grok 4 or Grok 4.5?
Grok 4.5 — released July 8, 2026, about 12 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.