ZMIME
Comparison · 3 models · Updated Oct 4, 2026

GPT-5.4 mini vs Grok 4.3 vs Claude Sonnet 4.5

Grok 4.3 comes out ahead, 67 to 63 and 55 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT-5.4 mini

    Released Mar 17, 2026

    63/100
    • ECI148.8
    • Price$0.75 / $4.50
    • Context400K
  2. Our pick

    xAI

    Grok 4.3

    Released Apr 17, 2026

    67/100
    • ECI149.2
    • Price$1.25 / $2.50
    • Context1M
  3. Anthropic

    Claude Sonnet 4.5

    Released Sep 29, 2025

    55/100
    • ECI146.8
    • Price$3.00 / $15.00
    • Context200K
01 — Verdict

Grok 4.3 is our pick

Grok 4.3 is the better all-round choice, scoring 67/100 against GPT-5.4 mini (63) and Claude Sonnet 4.5 (55). It leads on context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGrok 4.3Capabilities Index (ECI): Grok 4.3 149.2 · GPT-5.4 mini 148.8 · Claude Sonnet 4.5 146.8
  • Lowest priceGrok 4.3Grok 4.3 $1.56 · GPT-5.4 mini $1.69 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
  • Longest contextGrok 4.3Grok 4.3 1,000,000 · GPT-5.4 mini 400,000 · Claude Sonnet 4.5 200,000 tokens
  • Widest inputsGrok 4.3 and Claude Sonnet 4.5GPT-5.4 mini: Text, Images · Grok 4.3: Text, Images, PDFs · Claude Sonnet 4.5: Text, Images, PDFs
  • Self-hostingNo open weightsAll three are available only through APIs
How the score is built
MeasureWeightGPT-5.4 miniGrok 4.3Claude Sonnet 4.5
CapabilityCapabilities Index (ECI)50%777774
Price25%394113
Inputs & features15%708080
Context window10%446032
Overall100%63/10067/10055/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.4 mini vs Grok 4.3 vs Claude Sonnet 4.5 specifications side by side
SpecificationGPT-5.4 miniOpenAIGrok 4.3xAIClaude Sonnet 4.5Anthropic
Capability
Capabilities Index (ECI)148.8149.2 (best)146.8
ECI rank#56 of 148#55 of 148 (best)#64 of 148
GPQA DiamondGraduate-level science questions86.9%88.8% (best)82.3%
FrontierMath Tiers 1–3Research-level mathematics51.2% (best)42.8%23.9%
OTIS Mock AIME 2024–2025Competition mathematics88.9%93.3% (best)77.8%
SWE-bench VerifiedFixing real GitHub issues——71.3%
SimpleQA VerifiedShort factual questions29.4%33.2% (best)30.7%
Price per million tokens
Input$0.75 (best)$1.25$3.00
Output$4.50$2.50 (best)$15.00
Cached input$0.075 (best)$0.20$0.30
Blended (3:1)$1.69$1.56 (best)$6.00
Long-context rateSame rateOver 200K: $2.50 / $5.00Same rate
Price sourceOfficial OpenAI APIOfficial xAI APIOfficial Anthropic API
Limits
Context window400,000 tokens1,000,000 tokens (best)200,000 tokens
Max output128,000 tokens (best)30,000 tokens64,000 tokens
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsNoYesYes
AudioNoNoNo
VideoNoNoNo
ReasoningYeslow · medium · high · xhighYeslow · medium · highYes
Tool callingYesYesYes
Structured outputYesYesYes
Availability
WeightsProprietaryProprietaryProprietary
API model IDgpt-5.4-minigrok-4.3claude-sonnet-4-5
API providers29 (best)2728
ReleasedMar 17, 2026Apr 17, 2026Sep 29, 2025
Knowledge cutoffAug 31, 2025—Jul 31, 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.4 mini$16.50
  • Grok 4.3$17.50
  • Claude Sonnet 4.5$60.00
04 — Questions

Which should you choose?

Which is better: GPT-5.4 mini, Grok 4.3 or Claude Sonnet 4.5?

Grok 4.3 is the better all-round choice, scoring 67/100 against GPT-5.4 mini (63) and Claude Sonnet 4.5 (55). It leads on context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.4 mini, Grok 4.3 or Claude Sonnet 4.5?

Grok 4.3 is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). GPT-5.4 mini costs $0.75 input / $4.50 output per million tokens (official OpenAI API price); Claude Sonnet 4.5 costs $3.00 input / $15.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $1.56 per million tokens for Grok 4.3 versus $1.69 for GPT-5.4 mini (1.1× as much) and $6.00 for Claude Sonnet 4.5 (3.8× as much).

Which scores higher on benchmarks?

Grok 4.3 scores higher on the Capabilities Index (ECI): Grok 4.3 149.2 (#55 of 148), GPT-5.4 mini 148.8 (#56 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). The confidence ranges of the top two overlap (147.6–150.8 vs 147.1–150.5), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.3 88.8%, GPT-5.4 mini 86.9%, Claude Sonnet 4.5 82.3%; FrontierMath Tiers 1–3 — GPT-5.4 mini 51.2%, Grok 4.3 42.8%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — Grok 4.3 93.3%, GPT-5.4 mini 88.9%, Claude Sonnet 4.5 77.8%; SimpleQA Verified — Grok 4.3 33.2%, Claude Sonnet 4.5 30.7%, GPT-5.4 mini 29.4%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.4 mini and Grok 4.3 yet, so there is no like-for-like coding score. On overall capability, Grok 4.3 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

Grok 4.3 has the largest context window at 1,000,000 tokens, against 400,000 for GPT-5.4 mini and 200,000 for Claude Sonnet 4.5. Maximum output per response: GPT-5.4 mini up to 128,000, Grok 4.3 up to 30,000, Claude Sonnet 4.5 up to 64,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.4 mini accepts text and images; Grok 4.3 accepts text, images and PDFs; Claude Sonnet 4.5 accepts text, images and PDFs. Grok 4.3 handles the widest range of inputs.

Are any of these open source?

No. GPT-5.4 mini, Grok 4.3 and Claude Sonnet 4.5 are proprietary and only available through APIs and apps.

Which is newer?

Grok 4.3 is the newest, released Apr 17, 2026. GPT-5.4 mini came out Mar 17, 2026; Claude Sonnet 4.5 came out Sep 29, 2025. Knowledge cutoff: GPT-5.4 mini Aug 31, 2025, Claude Sonnet 4.5 Jul 31, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.