GPT-6.1 Sol vs GPT-6 Astra: when the cheaper model is enough

Key takeaways

GPT-6.1 Sol is the cheaper Sol-class model for coding, computer use, and professional work.
GPT-6 Astra remains the premium top tier in the same family (Astra review).
Short-context Standard list: Sol about $2/$10, Astra about $10/$50 per 1M in/out (~5×).
Sol’s cached input (~$0.10 / 1M) is a major reason agents should try Sol first.
Rule of thumb: Sol default, Astra exception.

Quick answer
Price ratio
Task fit
Availability
Migration pattern
FAQ

Quick answer

Start new coding and computer-use workloads on GPT-6.1 Sol. Move specific workflows to Astra only when your evals show a quality gap you care about. Paying Astra rates for every loop “just in case” is how OpenAI bills become a surprise.

Sol is the near-Astra workhorse at roughly one-fifth standard token prices. Astra is the premium lane when Sol is not good enough on your hardest tasks.

Last verified: October 2026.

Price ratio

Short-context Standard API list prices (OpenAI docs, Oct 2026):

Meter	GPT-6.1 Sol	GPT-6 Astra	Approx ratio
Input / 1M	$2.00	$10.00	~5×
Cached input / 1M	$0.10	$1.00	~10×
Cache writes / 1M	$2.50	$12.50	~5×
Output / 1M	$10.00	$50.00	~5×

Also remember:

Long context raises both models.
Fast mode is about 2× Standard where offered.
Batch / Flex cut Standard rates (Sol docs cite 50%).

If your agent rereads a huge system prompt every turn, Sol’s cached input gap can matter more than the raw input sticker.

Task fit

Situation	Prefer Sol	Prefer Astra
Everyday coding agents	Yes	Only if Sol fails
Computer-use loops with heavy tokens	Yes, especially with cache	When reliability gaps show
Hardest multi-hour agent tasks	Try Sol first	Keep as escape hatch
“We need the top OpenAI tier in marketing”	No	Yes (budget permitting)
OpenAI Dots always-on agent product	N/A (Dots use Astra)	Product engine, not your IDE default

What Sol is not:

A free ChatGPT Chat upgrade (Work/Codex/API only at launch)
A reason to ignore Claude, Grok, or Muse Spark if those stacks already win your harness

See the wider shortlist: Sol vs Sonnet 5.5 vs Grok 4.7 vs Muse Spark.

Availability

Surface	Sol	Astra
OpenAI API	`gpt-6.1-sol`	`gpt-6-astra` (confirm live id)
ChatGPT Work	Yes (Plus+)	Plan/routing dependent
Codex	Yes (Plus+)	Plan/routing dependent
ChatGPT Chat	No at Sol launch	Routing depends on plan
Free / Go	No	Limited / not the point

Enterprise and Edu often keep newer models off until an admin enables them.

Migration pattern

A sane rollout for a product or platform team:

Pin Sol as the default model id in staging.
Replay your top 20 agent traces (coding + computer use).
Score failures that matter (wrong edits, tool loops, policy breaks).
Route only failing task classes to Astra.
Revisit monthly as prompts and tools change.

A simple way to think about it: Sol is the fleet car. Astra is the tow truck and the executive sedan. Most miles should not be towed.

FAQ

Is GPT-6.1 Sol as good as GPT-6 Astra?

OpenAI positions Sol as near-Astra on coding, computer use, and professional work, not as a full replacement on every task. Run evals. Promote to Astra when Sol fails your quality gates.

How much cheaper is GPT-6.1 Sol than Astra?

On short-context Standard API list prices, Sol is about $2/$10 per 1M input/output versus Astra at about $10/$50. That is roughly one-fifth on those meters. Cached input is also much cheaper on Sol (~$0.10 vs ~$1.00 per 1M).

Should I use Sol or Astra for coding agents?

Default to Sol for most agent loops, especially when prompts are cached. Keep Astra for the hardest tasks where Sol regressions show up in your harness.

Is Astra required for OpenAI Dots?

Dots are powered by GPT-6 Astra as the agent engine. That is separate from whether your Codex/Work sessions use Sol. Dots are a product; Sol vs Astra is a model choice.