What is the best alternative to o3?

GPT-5.6 Terra is the closest model that scores higher on the BenchLeader Index (61.1 against 61.0). For less money, GPT-6.1 Terra scores 65.2 at $2.00 per 1M tokens.

Is there a cheaper alternative to o3?

Yes: GPT-6.1 Terra (65.2, $2.00), Gemini 3.5 Flash (62.5, $3.38) and Qwen3.6 Max (62.4, $2.96), each within 4 Index points and cheaper than o3's $3.50.

Is there an open-source alternative to o3?

The best open-weights models on the BenchLeader Index are Kimi K3 (62.1), GLM-5 (60.2) and GLM 5.2 (60.1). You can download and run them yourself; check each licence on its model page.

How are these alternatives chosen?

From the models ranked on the BenchLeader Index today: the ones just above o3, cheaper ones within 4 points, ones at least 1.5× as fast within 4 points, and the best open-weights models. Prices are list prices blended three input tokens to one output.

OpenAI

o3 alternatives

Data as of 2 Nov 2026 · ranked on the BenchLeader Index

As of 2 Nov 2026, o3 by OpenAI scores 61.0 on the BenchLeader Index at $3.50 per 1M tokens blended. GPT-5.6 Terra scores higher (61.1); GPT-6.1 Terra is the best cheaper model within 4 points (65.2 at $2.00); Muse Spark 1.2 is at least 1.5× as fast at a similar score; Kimi K3 is the best open-weights option (62.1).

Scores higher

The closest models above o3 on the Index.

GPT-5.6 Terra OpenAI compare61.1 · $4.50
Gemini 3.6 Flash Google compare61.3 · $1.50
Kimi K3.1 Pro Moonshot AI61.5 · $4.00

Cheaper, nearly as good

Within 4 Index points, for less per token.

GPT-6.1 Terra OpenAI65.2 · $2.00
Gemini 3.5 Flash Google62.5 · $3.38
Qwen3.6 Max Alibaba compare62.4 · $2.96
Gemini 3.7 Flash Google compare62.2 · $1.50
Muse Spark 1.1 Meta62.2 · $2.00

Faster

At least 1.5× the output speed, within 4 points.

Muse Spark 1.2 Meta compare61.6 · $2.00
Grok 4.20 Multi-Agent SpaceXAI58.4 · $1.56

Open weights

The best models whose weights you can run yourself.

Kimi K3 Moonshot AI62.1 · $6.00
GLM-5 Zhipu AI60.2 · $1.55
GLM 5.2 Zhipu AI60.1 · $2.15

Every alternative side by side

Model	Index	$ / 1M blended	Tokens / s	Why
o3 (this model)	61.0	$3.50	160	–
GPT-6.1 Terra	65.2	$2.00	107	cheaper
Gemini 3.5 Flash	62.5	$3.38	190	cheaper
Qwen3.6 Max	62.4	$2.96	–	cheaper
Gemini 3.7 Flash	62.2	$1.50	91	cheaper
Muse Spark 1.1	62.2	$2.00	206	cheaper
Kimi K3	62.1	$6.00	66	open weights
Muse Spark 1.2	61.6	$2.00	296	faster
Kimi K3.1 Pro	61.5	$4.00	31	scores higher
Gemini 3.6 Flash	61.3	$1.50	197	scores higher
GPT-5.6 Terra	61.1	$4.50	130	scores higher
GLM-5	60.2	$1.55	62	open weights
GLM 5.2	60.1	$2.15	89	open weights
Grok 4.20 Multi-Agent	58.4	$1.56	362	faster

Prices are list prices blended three input tokens to one output; speeds are measured medians, credited on each model page. The Index is BenchLeader's own, from independent benchmarks.

Questions people ask

What is the best alternative to o3?: GPT-5.6 Terra is the closest model that scores higher on the BenchLeader Index (61.1 against 61.0). For less money, GPT-6.1 Terra scores 65.2 at $2.00 per 1M tokens.
Is there a cheaper alternative to o3?: Yes: GPT-6.1 Terra (65.2, $2.00), Gemini 3.5 Flash (62.5, $3.38) and Qwen3.6 Max (62.4, $2.96), each within 4 Index points and cheaper than o3's $3.50.
Is there an open-source alternative to o3?: The best open-weights models on the BenchLeader Index are Kimi K3 (62.1), GLM-5 (60.2) and GLM 5.2 (60.1). You can download and run them yourself; check each licence on its model page.
How are these alternatives chosen?: From the models ranked on the BenchLeader Index today: the ones just above o3, cheaper ones within 4 points, ones at least 1.5× as fast within 4 points, and the best open-weights models. Prices are list prices blended three input tokens to one output.