ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Claude Sonnet 4.5 vs Inkling

Inkling comes out ahead, 59 to 55 on our weighted score, and it is the cheaper option too.

  1. Anthropic

    Claude Sonnet 4.5

    Released Sep 29, 2025

    55/100
    • ECI146.8
    • Price$3.00 / $15.00
    • Context200K
    Full specs Remove Claude Sonnet 4.5
  2. Our pick

    Thinking Machines

    Inkling

    Released Jul 15, 2026

    59/100
    • ECI148.6
    • Price$3.74 / $9.36
    • Context1.05M
    Full specs Remove Inkling

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Inkling is our pick

Inkling is the better all-round choice, scoring 59/100 against Claude Sonnet 4.5 (55). It leads on capability, price and context window. Claude Sonnet 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityInklingCapabilities Index (ECI): Inkling 148.6 · Claude Sonnet 4.5 146.8
  • Lowest priceInklingInkling $5.14 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
  • Longest contextInklingInkling 1,048,576 · Claude Sonnet 4.5 200,000 tokens
  • Widest inputsSame inputsClaude Sonnet 4.5: Text, Images, PDFs · Inkling: Text, Images, Audio
  • Self-hostingInklingPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightClaude Sonnet 4.5Inkling
CapabilityCapabilities Index (ECI)50%7476
Price25%1316
Inputs & features15%8070
Context window10%3261
Overall100%55/10059/100
02 — Side by side

Every spec in one table

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

Claude Sonnet 4.5 vs Inkling specifications side by side
SpecificationClaude Sonnet 4.5AnthropicInklingThinking Machines
Capability
Capabilities Index (ECI)146.8148.6 (best)
ECI rank#64 of 148#57 of 148 (best)
GPQA DiamondGraduate-level science questions82.3%88.3% (best)
FrontierMath Tiers 1–3Research-level mathematics23.9%33.3% (best)
OTIS Mock AIME 2024–2025Competition mathematics77.8%88.9% (best)
SWE-bench VerifiedFixing real GitHub issues71.3%—
SimpleQA VerifiedShort factual questions30.7%40.3% (best)
Price per million tokens
Input$3.00 (best)$3.74
Output$15.00$9.36 (best)
Cached input$0.30 (best)$0.748
Blended (3:1)$6.00$5.14 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Anthropic APIOfficial Thinking Machines API
Limits
Context window200,000 tokens1,048,576 tokens (best)
Max output64,000 tokens1,048,576 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoYes
VideoNoNo
ReasoningYesYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpenApache-2.0
API model IDclaude-sonnet-4-5thinkingmachines/Inkling:peft:262144
API providers28 (best)23
ReleasedSep 29, 2025Jul 15, 2026
Knowledge cutoffJul 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.

  • Claude Sonnet 4.5$60.00
  • Inkling$56.12
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 4.5 or Inkling?

Inkling is the better all-round choice, scoring 59/100 against Claude Sonnet 4.5 (55). It leads on capability, price and context window. Claude Sonnet 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Sonnet 4.5 or Inkling?

Inkling is cheaper at $3.74 input / $9.36 output per million tokens (official Thinking Machines 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 $5.14 per million tokens for Inkling versus $6.00 for Claude Sonnet 4.5 (1.2× as much).

Which scores higher on benchmarks?

Inkling scores higher on the Capabilities Index (ECI): Inkling 148.6 (#57 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). The confidence ranges of the top two overlap (145.7–150.6 vs 145.3–148.5), so treat the gap as small. On individual benchmarks: GPQA Diamond — Inkling 88.3%, Claude Sonnet 4.5 82.3%; FrontierMath Tiers 1–3 — Inkling 33.3%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — Inkling 88.9%, Claude Sonnet 4.5 77.8%; SimpleQA Verified — Inkling 40.3%, Claude Sonnet 4.5 30.7%.

Which is better for coding?

There are no published SWE-bench Verified results for Inkling yet, so there is no like-for-like coding score. On overall capability, Inkling leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

Inkling has the largest context window at 1,048,576 tokens, against 200,000 for Claude Sonnet 4.5. Maximum output per response: Claude Sonnet 4.5 up to 64,000, Inkling up to 1,048,576 tokens.

Which can read images, PDFs, audio or video?

Claude Sonnet 4.5 accepts text, images and PDFs; Inkling accepts text, images and audio. They handle the same number of input types.

Are any of these open source?

Inkling publishes its weights (Apache-2.0) and can be self-hosted; Claude Sonnet 4.5 is proprietary.

Which is newer?

Inkling is the newest, released Jul 15, 2026. Claude Sonnet 4.5 came out Sep 29, 2025. Knowledge cutoff: 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.

05 — Keep comparing

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