Undominated.ai

Cheaper alternatives to GPT-5.5

OpenAI LMArena 1470.9 $11.25/M on a balanced workload prices as of 2026-08-28

Everything cheaper and higher-scoring gives something up.

Of the 133 models carrying both an independent score and a published price at the same delivery mode, 11 score at least as high as GPT-5.5 and cost no more under at least one workload. 11 do not, and every row names what it drops.

Dominance is not a property of a model. It is a property of a model, a capability lens and a workload, and all three are named on every row. Scores are LMArena Elo, used under CC BY 4.0 from the official dataset; prices are blended per million tokens. A higher score is not a drop-in replacement.

This page is built from that comparison and nothing else. When no model is both better and cheaper than GPT-5.5, it is not generated.

Where it holds

WorkloadGPT-5.5 $/MBetter and cheaperWith a trade
Balanced$11.25011
Summarise$4.97011
Chat$13.65011
Code gen$19.64011
Agentic$6.07011

Workload mixes are defined on the methodology page. Cached input is priced at the cached rate, and reasoning tokens at the worse of the reasoning and output rates.

What you would be replacing

Intelligence1470.9
Context window1.1M
Max output128K
Input modesfile, image, text
Tool useyes
Extended reasoningyes

A replacement has to clear every line above, not just the score. Full record for GPT-5.5.

Cheaper and higher-scoring, but you give something up 11

These score at least as high and cost no more on the two plotted axes, and lose something that is not on them. Read the last column before switching.

ModelIntelligence$/MHolds underWhat you give up
Claude Opus 5 Anthropic1504.2 +33.3$10.00
  • Balanced −11%
  • Summarise −5%
  • Chat −15%
  • Code gen −15%
  • Agentic −12%
  • 1.1M → 1.0M context
Claude Opus 4.6 Anthropic1502.7 +31.8$10.00
  • Balanced −11%
  • Summarise −5%
  • Chat −15%
  • Code gen −15%
  • Agentic −12%
  • 1.1M → 1.0M context
Gemini 3.7 Flash Google1490.2 +19.3$0.750
  • Balanced −93%
  • Summarise −93%
  • Chat −94%
  • Code gen −94%
  • Agentic −93%
  • 1.1M → 1.0M context
  • 128K → 66K max output
Claude Opus 4.7 Anthropic1490.1 +19.2$10.00
  • Balanced −11%
  • Summarise −5%
  • Chat −15%
  • Code gen −15%
  • Agentic −12%
  • 1.1M → 1.0M context
Gemini 3.5 Flash Google1482.6 +11.7$3.38
  • Balanced −70%
  • Summarise −70%
  • Chat −70%
  • Code gen −70%
  • Agentic −70%
  • 1.1M → 1.0M context
  • 128K → 66K max output
Qwen3.8 Max Qwen1481.9 +11$3.00
  • Balanced −73%
  • Summarise −66%
  • Chat −77%
  • Code gen −78%
  • Agentic −74%
  • 1.1M → 1.0M context
  • no file input
Muse Spark 1.1 Meta1478.3 tie$2.00
  • Balanced −82%
  • Summarise −78%
  • Chat −84%
  • Code gen −85%
  • Agentic −83%
  • 1.1M → 1.0M context
Gemini 3.1 Pro Preview Google1479.5 tie$4.50
  • Balanced −60%
  • Summarise −60%
  • Chat −60%
  • Code gen −60%
  • Agentic −60%
  • 1.1M → 1.0M context
  • 128K → 66K max output
Gemini 3.6 Flash Google1476.5 tie$1.50
  • Balanced −87%
  • Summarise −86%
  • Chat −87%
  • Code gen −87%
  • Agentic −87%
  • 1.1M → 1.0M context
  • 128K → 66K max output
GLM 5.3 Z.ai1476.9 tie$2.15
  • Balanced −81%
  • Summarise −75%
  • Chat −83%
  • Code gen −84%
  • Agentic −81%
  • 1.1M → 1.0M context
  • no file, image input
Kimi K3 Moonshot AI1476.3 tie$6.00
  • Balanced −47%
  • Summarise −43%
  • Chat −49%
  • Code gen −49%
  • Agentic −47%
  • 1.1M → 1.0M context
  • no file input

What this compares, and what it leaves out

  • Quality is LMArena Elo, used under CC BY 4.0 from the official dataset. The 95% confidence interval on a difference between two scores is about ±10.68 points, so a gap smaller than that is marked tie rather than an improvement — see significance bands.
  • 188 further models at this delivery mode carry a price but no independent score. They are absent from the comparison in both directions — unrated is not a zero, and an unmeasured model is neither an alternative nor a worse buy.
  • Retired models are never offered as an alternative, and a model only competes against its own delivery mode: batch trades latency for price, so it is not a like-for-like swap.
  • Nothing here measures latency, throughput, rate limits or how a model behaves on your prompts. Two models with the same index score are not interchangeable.
  • The models that nothing beats on both axes are on the value frontier, and every other model something cheaper beats is listed here.