GPT-4o vs GPT-5.6 Luna
Benchmark Performance
Available Benchmarks
| Benchmark | GPT-4o | GPT-5.6 Luna |
|---|---|---|
| LMArena Text Arenatext-2026-09-01-011508720696 · arena_rating · leader | 1,282.3390% of row best · rating · gpt-4o-2024-08-06; 95% CI [1278.14385443, 1286.52509361]; votes 45499; rank 250 | 1,430.14100% of row best · rating · gpt-5.6-luna-xhigh; 95% CI [1425.14784950, 1435.13857729]; votes 24433; rank 82 |
| LMArena Vision Arenavision-2026-08-27-011508720696 · arena_rating · leader | 1,064.5485% of row best · rating · gpt-4o-2024-08-06; 95% CI [1052.10281463, 1076.97369812]; votes 3376; rank 119 | 1,254.30100% of row best · rating · gpt-5.6-luna-xhigh; 95% CI [1245.05722338, 1263.53552757]; votes 5857; rank 45 |
| ToneBench2026-08-14-10-task · overall_score · leader | 57.1768% of row best · points · GPT-4o · 1,184 output tokens / case | 83.59100% of row best · points · GPT-5.6 Luna (xhigh) · 6,093 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 0 benchmark wins | 3 benchmark winsOverall lead |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | GPT-4o | GPT-5.6 Luna |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 4o | Gpt 5 6 |
| Model | GPT-4o | GPT-5.6 Luna |
| Version | GPT-4o | GPT-5.6 Luna |
| Lifecycle | active | active |
| Released | Unknown | Unknown |
| Knowledge cutoff | 2023-10-01 | 2026-02-16 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 128,000 | 1,050,000 |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | OpenAI (Standard), Openrouter (Standard) | OpenAI (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, tools | chat, generation, reasoning, tools |
14 comparable fields · 6 material differences · Pair passes the primary-source comparison gate
GPT-4o Capabilities
GPT-5.6 Luna Capabilities
Internal Comparison Graph
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|---|---|---|---|
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Primary Evidence
Sources and Freshness
Questions
GPT-4o vs GPT-5.6 Luna FAQs
Is GPT-4o or GPT-5.6 Luna better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-4o and GPT-5.6 Luna, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-4o or GPT-5.6 Luna?+
GPT-4o is $2.50 and GPT-5.6 Luna is $0.20 per million tokens, so GPT-5.6 Luna is cheaper on this metric. GPT-4o is $10.00 and GPT-5.6 Luna is $1.20 per million tokens, so GPT-5.6 Luna is cheaper on this metric.
Which has a larger context window, GPT-4o or GPT-5.6 Luna?+
GPT-5.6 Luna has the larger sourced context window. GPT-4o supports 128,000 and GPT-5.6 Luna supports 1,050,000.
Which performs better in benchmarks, GPT-4o or GPT-5.6 Luna?+
GPT-5.6 Luna leads the current overall benchmark count. The result uses 3 protocol-matched benchmarks from 2 publishers; it is not a universal quality score.
Can GPT-4o or GPT-5.6 Luna be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-4o is not marked open weight; GPT-5.6 Luna is not marked open weight.
Can GPT-4o and GPT-5.6 Luna understand images?+
GPT-4o is documented with image input; GPT-5.6 Luna is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-4o or GPT-5.6 Luna?+
GPT-5.6 Luna has the larger sourced maximum output: GPT-4o supports 16,384 and GPT-5.6 Luna supports 128,000 output tokens.
Do GPT-4o and GPT-5.6 Luna support reasoning and tool use?+
GPT-4o: tool calling and image input. GPT-5.6 Luna: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-4o or GPT-5.6 Luna?+
GPT-4o has 2 sourced provider routes; GPT-5.6 Luna has 2, a tie.
Which offers better value, GPT-4o or GPT-5.6 Luna?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.