AI Models · Compare

GPT-5.5 vs Grok 3

Which AI model is better in 2026? Compare GPT-5.5 and Grok 3 on benchmarks, pricing, speed, context window, and real-world fit.

Quick summary

GPT-5.5 is currently the stronger overall pick for reasoning, coding, math, and speed. Grok 3 wins on context and price. Grok 3 remains the budget pick at $6.00 vs $7.50 blended / 1M tokens.

Overall winner

GPT-5.5

View GPT-5.5 review

GPT-5.5 wins

  • Reasoning
  • Coding
  • Math
  • Speed

Grok 3 wins

  • Context
  • Price

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OpenAI

GPT-5.5

ProprietaryMar 2026

OpenAI’s 2026 flagship — strongest at reasoning, coding and tool use.

Open docs
xAI

Grok 3

ProprietaryFeb 2025

Real-time data via X — competitive on reasoning, 1M context.

Open docs

GPT-5.5 vs Grok 3: overview

GPT-5.5 (OpenAI) and Grok 3 (xAI) are frequently compared by teams choosing an AI stack in 2026. GPT-5.5: OpenAI’s 2026 flagship — strongest at reasoning, coding and tool use. Grok 3: Real-time data via X — competitive on reasoning, 1M context. This GPT-5.5 vs Grok 3 comparison covers benchmarks, pricing, context window, speed, modalities, strengths, weaknesses, and who should pick which model.

GPT-5.5 is proprietary with a 400k-token context window and a blended API price near $7.50 / 1M tokens (intelligence index 82/100). Grok 3 is proprietary with 1M context at about $6.00 blended / 1M (intelligence 74/100). Those gaps drive most “GPT-5.5 vs Grok 3” searches — quality versus cost, closed versus open, cloud versus self-host.

Where they differ most: GPT-5.5 tends to lead on reasoning, coding, math, and speed, while Grok 3 leads on context and price. Choose GPT-5.5 when you want the stronger overall profile on our scorecard; validate with your own evals before migrating production traffic.

GPT-5.5 is often shortlisted for agentic workflows, complex coding, and hard math & research. Grok 3 fits real-time research and social-aware apps. Scroll to pricing, real-world tasks, and the who-should-choose section for decision support.

People search “GPT-5.5 vs Grok 3”, “which is better”, and “GPT-5.5 vs Grok 3 pricing” for the same reason: switching models is expensive if quality drops, and staying put is expensive if you overpay. Use the winner card for a fast answer, the head-to-head table for receipts, and the editorial verdict for a human recommendation. GPT-5.5 currently ranks among frontier options from OpenAI; Grok 3 is a hosted alternative from xAI. If API pricing is your main concern, start with the pricing section; for multimodal workloads, check vision/audio rows in technical differences; for agents and long documents, prioritize context and reasoning wins.

Head to head

Spec
GPT-5.5
Grok 3
Winner
Reason
Intelligence index↑ better
Winner82
74
GPT-5.5
GPT-5.5 leads on the composite intelligence index (82 vs 74).
Speed↑ better
Winner95 tok/s
75 tok/s
GPT-5.5
GPT-5.5 generates tokens faster (95 vs 75 tok/s).
Time to first token↓ better
Winner0.42 s
0.6 s
GPT-5.5
GPT-5.5 starts streaming sooner (0.42s vs 0.6s TTFT).
Context window↑ better
400k
Winner1M
Grok 3
Grok 3 wins with 1M tokens — about 2.5× GPT-5.5.
Max output↑ better
16k
16k
Tie
Even — no meaningful gap in our catalog.
Input price↓ better
$5.00 / 1M tokens
Winner$3.00 / 1M tokens
Grok 3
Grok 3 is cheaper (~1.7× lower on this price row).
Output price↓ better
$15.00 / 1M tokens
$15.00 / 1M tokens
Tie
Even — no meaningful gap in our catalog.
Blended price↓ better
$7.50 / 1M tokens
Winner$6.00 / 1M tokens
Grok 3
Grok 3 is cheaper (~1.3× lower on this price row).
License
Proprietary
Proprietary
Qualitative / categorical row
Input modalities
text, image
text, image
Qualitative / categorical row
Output modalities
text
text
Qualitative / categorical row

Pricing comparison

API cost is often the deciding factor in GPT-5.5 vs Grok 3 for high-volume apps. Figures below use catalog list prices with a 3:1 input:output blend for monthly estimates. Cached input, batch, and realtime surcharges vary by provider — confirm on official docs.

API costGPT-5.5Grok 3
Input / 1M tokens$5.00$3.00
Output / 1M tokens$15.00$15.00
Blended (3:1) / 1M$7.50$6.00
Est. cost @ 1M blended tokens$7.50$6.00
Est. cost @ 10M blended tokens$75.00$60.00
Est. cost @ 100M blended tokens$750.00$600.00

Cached input, batch API, and realtime surcharges are provider-specific and not always published in our catalog — verify on official pricing pages.

Benchmark showdown

MMLU
GPT-5.5
90.2
Grok 3
88.0
MMLU Pro
GPT-5.5
78.0
Grok 3
76.0
GPQA
GPT-5.5
62.5
Grok 3
62.0
MATH
GPT-5.5
89.1
Grok 3
88.5
HumanEval
GPT-5.5
93.0
Grok 3
90.0

GPT-5.5 leads on MMLU, MMLU Pro, GPQA, MATH, and HumanEval, indicating stronger coding and reasoning-oriented scores. Grok 3 remains attractive for production deployments on price. Raw benchmarks shortlist models — run task-specific evals before you switch.

Real-world performance

Beyond academic scores, here is how GPT-5.5 vs Grok 3 tends to split common product tasks based on catalog strengths, price, and modalities.

TaskWinner
CodingGPT-5.5
Blog writingGPT-5.5
ResearchGrok 3
Customer supportGrok 3
Cheap API / high volumeGrok 3
AI agentsGrok 3
SummarizationGPT-5.5
TranslationGPT-5.5
Vision / multimodalGPT-5.5
Self-hosting / open weightsGrok 3

Technical differences

FeatureGPT-5.5Grok 3
ProviderOpenAIxAI
LicenseProprietaryProprietary
Pricing modeltokenstokens
Context window400k tokens1M tokens
Max output16k tokens16k tokens
Vision inputYesYes
Audio inputNoNo
Text outputYesYes
Image outputNoNo
Video outputNoNo
Audio outputNoNo
Self-host friendlyNoNo
DocsAvailableAvailable

Strengths, weaknesses and best-for

GPT-5.5
Strengths
  • Best-in-class reasoning
  • Huge 400k context
  • Strong tool use and agents
Weaknesses
  • Expensive vs Sonnet for non-reasoning tasks
  • Higher latency than gpt-5.5-mini
Best for
  • Agentic workflows
  • Complex coding
  • Hard math & research
Grok 3
Strengths
  • Live X data
  • 1M context
  • Strong reasoning mode
Weaknesses
  • Smaller ecosystem
  • Less tool-use tooling
Best for
  • Real-time research
  • Social-aware apps

Who should choose which

Choose GPT-5.5 if

  • You need stronger reasoning, coding, or math quality
  • You care about faster token throughput
  • Agentic workflows
  • Complex coding

Choose Grok 3 if

  • You need a larger context window
  • API budget is the top constraint
  • Real-time research
  • Social-aware apps

Pros & cons

GPT-5.5

Pros

  • Best-in-class reasoning
  • Huge 400k context
  • Strong tool use and agents

Cons

  • Expensive vs Sonnet for non-reasoning tasks
  • Higher latency than gpt-5.5-mini

Grok 3

Pros

  • Live X data
  • 1M context
  • Strong reasoning mode

Cons

  • Smaller ecosystem
  • Less tool-use tooling

Editorial verdict

GPT-5.5 edges this matchup — with caveats

GPT-5.5 is the better choice when you prioritize reasoning, coding, math, and speed. Grok 3 stands out for context and price, making it a strong option when those dimensions matter more than raw leaderboard rank. If maximum measured performance matters, GPT-5.5 wins this matchup. If cost and control matter more, Grok 3 is difficult to beat. Always confirm with a bake-off on your real prompts before cutting over.

Still deciding? Read the full GPT-5.5 review and Grok 3 review, or open the full AI models table.

GPT-5.5 vs Grok 3 — frequently asked questions

On our scorecard, GPT-5.5 wins overall (leads on Reasoning, Coding, Math, and Speed). The “better” model still depends on your workload — validate with your own evals.

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