Cheapest reasoning AI model
Reasoning models (OpenAI o-series, DeepSeek R1, Claude thinking variants) burn output tokens internally before generating their reply. We benchmarked at 500 input + 3,000 output, which captures the reality of reasoning output volume. Note: not every model below is a true reasoning model — the ranking simply shows which models are cheapest at that output-heavy shape.
Ranked cheapest first
| # | Model | Input $/M | Output $/M | Per 1M calls |
|---|---|---|---|---|
| #1 | Llama 3.1 8B Meta |
$0.18 | $0.18 | $630 |
| #2 | GPT-5 Nano OpenAI |
$0.05 | $0.40 | $1,225 |
| #3 | GPT-4.1 Nano OpenAI |
$0.10 | $0.40 | $1,250 |
| #4 | Gemini 2.5 Flash-Lite |
$0.10 | $0.40 | $1,250 |
| #5 | GPT-4o mini OpenAI |
$0.15 | $0.60 | $1,875 |
| #6 | Llama 3.1 70B Meta |
$0.59 | $0.79 | $2,665 |
| #7 | Qwen 2.5 Coder 32B Alibaba |
$0.80 | $0.80 | $2,800 |
| #8 | Llama 3.3 70B Meta |
$0.88 | $0.88 | $3,080 |
| #9 | Qwen 2.5 72B Alibaba |
$0.90 | $0.90 | $3,150 |
| #10 | DeepSeek V3 DeepSeek |
$0.27 | $1.10 | $3,435 |
| #11 | GPT-5.4 Nano OpenAI |
$0.20 | $1.25 | $3,850 |
| #12 | Gemini 3.1 Flash-Lite |
$0.25 | $1.50 | $4,625 |
| #13 | GPT-4.1 Mini OpenAI |
$0.40 | $1.60 | $5,000 |
| #14 | DeepSeek V3.1 DeepSeek |
$0.60 | $1.70 | $5,400 |
| #15 | GPT-5 Mini OpenAI |
$0.25 | $2.00 | $6,125 |
| #16 | Qwen3 Coder 480B Alibaba |
$2.00 | $2.00 | $7,000 |
| #17 | Gemini 2.5 Flash |
$0.30 | $2.50 | $7,650 |
| #18 | Gemini 3 Flash |
$0.50 | $3.00 | $9,250 |
| #19 | Llama 3.1 405B Meta |
$3.50 | $3.50 | $12,250 |
| #20 | o3-mini OpenAI |
$1.10 | $4.40 | $13,750 |
| #21 | o4-mini OpenAI |
$1.10 | $4.40 | $13,750 |
| #22 | GPT-5.4 Mini OpenAI |
$0.75 | $4.50 | $13,875 |
| #23 | GLM-5.1 zhipu |
$1.40 | $4.40 | $13,900 |
| #24 | Claude Haiku 4.5 Anthropic |
$1.00 | $5.00 | $15,500 |
| #25 | Mistral Large Mistral |
$2.00 | $6.00 | $19,000 |
| #26 | DeepSeek R1 DeepSeek |
$3.00 | $7.00 | $22,500 |
| #27 | GPT-4.1 OpenAI |
$2.00 | $8.00 | $25,000 |
| #28 | o3 OpenAI |
$2.00 | $8.00 | $25,000 |
| #29 | GPT-5.1 OpenAI |
$1.25 | $10.00 | $30,625 |
| #30 | GPT-5 OpenAI |
$1.25 | $10.00 | $30,625 |
| #31 | Gemini 2.5 Pro |
$1.25 | $10.00 | $30,625 |
| #32 | GPT-4o OpenAI |
$2.50 | $10.00 | $31,250 |
| #33 | Gemini 3.1 Pro |
$2.00 | $12.00 | $37,000 |
| #34 | GPT-5.3 OpenAI |
$1.75 | $14.00 | $42,875 |
| #35 | GPT-5.2 OpenAI |
$1.75 | $14.00 | $42,875 |
| #36 | GPT-5.4 OpenAI |
$2.50 | $15.00 | $46,250 |
| #37 | Claude Sonnet 4.6 Anthropic |
$3.00 | $15.00 | $46,500 |
| #38 | Claude Opus 4.8 Anthropic |
$5.00 | $25.00 | $77,500 |
| #39 | GPT-5.5 OpenAI |
$5.00 | $30.00 | $92,500 |
| #40 | GPT-4 Turbo OpenAI |
$10.00 | $30.00 | $95,000 |
| #41 | Claude Opus 4.8 (Fast Mode) Anthropic |
$10.00 | $50.00 | $155,000 |
| #42 | o3-pro OpenAI |
$20.00 | $80.00 | $250,000 |
| #43 | GPT-5 Pro OpenAI |
$15.00 | $120.00 | $367,500 |
| #44 | GPT-5.2 Pro OpenAI |
$21.00 | $168.00 | $514,500 |
| #45 | GPT-5.5 Pro OpenAI |
$30.00 | $180.00 | $555,000 |
| #46 | GPT-5.4 Pro OpenAI |
$30.00 | $180.00 | $555,000 |
Workload assumption: 500 input tokens + 3,000 output tokens per call, scaled to 1M calls. Pricing as of 2026-05-31.
How to use this ranking
The winner is mathematically cheapest at the listed workload shape — that's not the same as "best for the use case." Cheaper models often have lower reasoning depth, smaller context windows, or worse instruction-following. Use this as the cost baseline, then test the top 2-3 candidates on your real prompts via the live counter.
Pricing snapshots come from each provider's published rate cards and are tracked in the full pricing changelog. Tokenizer accuracy per model is documented in the methodology.