Which is cheaper, GPT-6.1 Sol and Inkling Small?

Inkling Small has the lowest input price. Per 1M input tokens: GPT-6.1 Sol from $2.00 and Inkling Small from $0.45.

Which has the larger context window, GPT-6.1 Sol and Inkling Small?

GPT-6.1 Sol has the largest context window: GPT-6.1 Sol 1,050,000 tokens and Inkling Small 524,288 tokens.

Which is smarter, GPT-6.1 Sol and Inkling Small?

GPT-6.1 Sol scores highest on the Artificial Analysis Intelligence Index: GPT-6.1 Sol 54.6 and Inkling Small 12.9.

Can I switch between GPT-6.1 Sol and Inkling Small without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (openai/gpt-6.1-sol, thinkingmachines/inkling-small).

GPT-6.1 Sol vs Inkling Small

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Estimate monthly cost for these models

GPT-6.1 Sol OpenAIopenai/gpt-6.1-sol

Inkling Small Thinking Machinesthinkingmachines/inkling-small

Creator

OpenAI

Thinking Machines

Released

Sep 29, 2026

Jul 30, 2026

Context window

1.05M

524K

Max output

128K

262K

Input / 1MLowest provider price

$2.00

$0.45

Output / 1MLowest provider price

$10.00

$1.20

Providers

IntelligenceArtificial Analysis index

54.6

12.9

Accepts

Text, Image, Files

Text, Image, Audio

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

GPT-6.1 Sol vs Inkling Small: summary

GPT-6.1 Sol and Inkling Small are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

GPT-6.1 Sol, from OpenAI, has a 1,050,000-token context window, costs $2.00/1M input and $10.00/1M output tokens and scores 54.6 on the Artificial Analysis Intelligence Index.

Inkling Small, from Thinking Machines, has a 524,288-token context window, costs $0.45/1M input and $1.20/1M output tokens and scores 12.9 on the Artificial Analysis Intelligence Index.

Inkling Small is the cheapest on input, 4.4× cheaper than the next model, GPT-6.1 Sol has the largest context window and GPT-6.1 Sol scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="openai/gpt-6.1-sol", messages=[...]) # or client.chat.completions.create(model="thinkingmachines/inkling-small", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis