Claude Sonnet 4.6 vs GPT-6 Sol

Anthropic · US  |  OpenAI · US · Updated June 2026

Quick verdict

Pick Claude Sonnet 4.6 for best value in the claude family or everyday professional work. Pick GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment or openai says it makes about half as many mistakes as gpt-5.6 sol. On a tight budget at scale, GPT-6 Sol is the value pick.

Claude Sonnet 4.6 (Anthropic) and GPT-6 Sol (OpenAI) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.6 is opus-class quality at lower cost; superseded as the default Sonnet by Claude Sonnet 5 (June 2026). GPT-6 Sol is openAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecClaude Sonnet 4.6GPT-6 Sol
ProviderAnthropic (US) OpenAI (US)
ReleasedFebruary 17, 2026 September 22, 2026
Context window1M (~1,500 pages) 1.05M tokens (~1,575 pages)
Price (in/out)$3/$15 per 1M tokens $2/$10 per 1M tokens
Open weight?No — API only No — API only
Modalitiestext, image, code text, image
SWE-Bench Verified79.6% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Best value in the Claude family

Claude Sonnet 4.6

Claude Sonnet 4.6 lists best value in the Claude family among its strengths; GPT-6 Sol does not.

Everyday professional work

Claude Sonnet 4.6

Claude Sonnet 4.6 lists everyday professional work among its strengths; GPT-6 Sol does not.

Long-document analysis

Claude Sonnet 4.6

Claude Sonnet 4.6 lists long-document analysis among its strengths; GPT-6 Sol does not.

OpenAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment

GPT-6 Sol

OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens — and it runs cheaper at $2/$10 per 1M tokens.

OpenAI says it makes about half as many mistakes as GPT-5.6 Sol

GPT-6 Sol

OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens — and it is the newer of the two.

Priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30)

GPT-6 Sol

At $2/$10 per 1M tokens it undercuts Claude Sonnet 4.6 ($3/$15 per 1M tokens), and that gap compounds at volume.

Lowest cost at scale

GPT-6 Sol

At $2/$10 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Which should you pick?

A cost-sensitive startup shipping high volume

GPT-6 Sol

At $2/$10 per 1M tokens it undercuts Claude Sonnet 4.6, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GPT-6 Sol

Larger 1.05M tokens window fits more in one prompt.

Anyone whose priority is best value in the claude family

Claude Sonnet 4.6

It is specifically built for that.

Anyone whose priority is openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment

GPT-6 Sol

That is its strongest area.

Claude Sonnet 4.6: where it fits

Opus-class quality at lower cost; superseded as the default Sonnet by Claude Sonnet 5 (June 2026). Released February 17, 2026 by Anthropic, it is built for best value in the Claude family, everyday professional work, long-document analysis, and coding at lower cost than Opus.

Its trade-offs are real: trails Opus on the hardest agentic tasks, and not an open-weight option. At $3 in / $15 out per million tokens, it sits in the mid price band.

GPT-6 Sol: where it fits

OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Released September 22, 2026 by OpenAI, it is built for openAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment, openAI says it makes about half as many mistakes as GPT-5.6 Sol, priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30), and 1.05M-token context window, input capped at 922K.

Its trade-offs: more reasoning capability than sibling GPT-6 Luna, but still positioned below flagship GPT-6 Astra, and cache-read pricing ($0.20/MTok) still costlier than Luna's ($0.01/MTok) for high-cache workloads. At $2 in / $10 out per million tokens, it sits in the mid price band.

The bottom line for this matchup

Claude Sonnet 4.6 and GPT-6 Sol overlap enough that the right pick depends on your specific job. GPT-6 Sol costs less per token; GPT-6 Sol holds the larger context; and each leads in its own area — Claude Sonnet 4.6 for best value in the claude family, GPT-6 Sol for openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment. Rather than crowning one, run the same hard task through both once and let the results decide.

Want both Claude Sonnet 4.6 and GPT-6 Sol 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.

See pricing

Frequently asked questions

Is Claude Sonnet 4.6 or GPT-6 Sol better for coding?

Public SWE-Bench figures are not available for GPT-6 Sol, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.6 leans toward best value in the claude family while GPT-6 Sol leans toward openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Claude Sonnet 4.6 or GPT-6 Sol?

GPT-6 Sol is cheaper — $3/$15 per 1M tokens vs $2/$10 per 1M tokens, roughly 1.5× apart on input.

Which has the bigger context window?

Effectively neither — 1M vs 1.05M tokens is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.

Can I use both Claude Sonnet 4.6 and GPT-6 Sol together?

Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.6, GPT-6 Sol and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, Claude Sonnet 4.6 or GPT-6 Sol?

GPT-6 Sol — released September 22, 2026, about 7 months after Claude Sonnet 4.6.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.