Standard Compute
Model Comparison 2026

GPT-5.5 vs GPT-5.6 Terra

GPT-5.5
OpenAI · Frontier · Proprietary
$13/1M · 1.1M ctx
GPT-5.6 Terra
OpenAI · Balanced · Proprietary
$3.13/1M · 1.1M ctx

Community Vote

Pick a winner in each dimension — change your vote anytime. 3 votes cast so far.

Output Quality
Correctness and depth of what it produces
GPT-5.5 100%0% Terra
Agentic Ability
Tool calls, instruction-following, and multi-step tasks
GPT-5.5 0%100% Terra
Speed
Tokens per second and time-to-first-token
Value for $
How much capability you get per dollar
Reliability
Consistent results — fewer refusals, loops, and format breaks

Specs & Pricing, Side by Side

Spec
GPT-5.5
Terra
Maker
OpenAI
OpenAI
Blended price / 1M
$13
$3.13
Input / output
$5.00 in · $30 out / 1M tokens
$1.25 in · $7.50 out / 1M tokens
Context window
1.1M
1.1M
Open weights
No
No
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
9.6
9.0
Agentic Ability
9.5
9.0
Speed
7.0
8.4
Value for $
7.5
8.8
Reliability
9.0
9.2

Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).

Verdict: GPT-5.5 or Terra?

Updated 2026-08-02

Choose GPT-5.5 if you want hard reasoning and coding for teams in the OpenAI ecosystem. Choose GPT-5.6 Terra if you want the everyday OpenAI default for agents — volume work with frontier-adjacent quality.

In our editorial scoring, GPT-5.6 Terra leads in 3 of five dimensions (speed, value for $ and reliability), while GPT-5.5 leads in 2. On price, GPT-5.5 runs about $13 per 1M tokens (blended) and is proprietary; GPT-5.6 Terra is about $3.13 and proprietary.

Across 3 community votes on this matchup, the community has it tied. Cast your own vote above to move the needle.

Where GPT-5.5 falls short
  • Premium pricing
  • Slower than mini/flash tiers
Full GPT-5.5 breakdown →
Where Terra falls short
  • Steps behind Sol on the hardest tasks
  • Very new — long-run agent behavior still being characterized
Full Terra breakdown →

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