Cheapest reasoning LLMs
inclusionAI: Ling 3.0 Flash is the cheapest option at $0.021 per million input tokens. Reasoning models emit far more output tokens than they take in, so output price dominates the bill. These are ranked with that weighting in mind.
218 models qualify
Ranked by output price, because reasoning models bill mostly on tokens they generate.
| # | Model | Blended / 1M | Input / 1M | Output / 1M | Context | Capabilities |
|---|---|---|---|---|---|---|
| 1 | Auto Router (Beta) OpenRouter | $-1000000.0000 | $-1000000.0000 | $-1000000.0000 | 2M | ReasoningToolsVision |
| 2 | Auto Router OpenRouter | $-1000000.0000 | $-1000000.0000 | $-1000000.0000 | 2M | ReasoningToolsVision |
| 3 | Nex-N2.5-Mini (free) Nex AGI | Free | Free | Free | 262K | Free tierReasoningToolsVisionOpen weights |
| 4 | Nex-N2.5-Pro (free) Nex AGI | Free | Free | Free | 262K | Free tierReasoningToolsVisionOpen weights |
| 5 | Ling 3.0 Flash Sante (free) inclusionAI | Free | Free | Free | 262K | Free tierReasoningTools |
| 6 | Dots3-Note Preview (free) Dots Studio | Free | Free | Free | 512K | Free tierReasoningToolsVision |
| 7 | LFM2.5-2.6B (free) Liquid AI | Free | Free | Free | 66K | Free tierReasoningToolsOpen weights |
| 8 | North Mini Code (free) Cohere | Free | Free | Free | 256K | Free tierReasoningToolsOpen weights |
| 9 | Free | Free | Free | 256K | Free tierReasoningToolsVisionOpen weights | |
| 10 | Free Models Router OpenRouter | Free | Free | Free | 200K | Free tierReasoningToolsVision |
| 11 | Ling 3.0 Flash inclusionAI | $0.032 | $0.021 | $0.063 | 262K | ReasoningToolsOpen weights |
| 12 | DeepSeek V4 Flash 0731 DeepSeek | $0.075 | $0.060 | $0.120 | 1.3M | ReasoningToolsOpen weights |
| 13 | Laguna XS 2.1 Poolside | $0.075 | $0.060 | $0.120 | 262K | Free tierReasoningToolsOpen weights |
| 14 | Qwen3.7 Flash Qwen | $0.055 | $0.030 | $0.130 | 1M | ReasoningToolsVision |
| 15 | gpt-oss-20b OpenAI | $0.055 | $0.030 | $0.130 | 131K | ReasoningToolsOpen weights |
| 16 | Mercury 2.5 Inception | $0.068 | $0.040 | $0.150 | 260K | ReasoningTools |
| 17 | Qwen3.5-9B Qwen | $0.112 | $0.100 | $0.150 | 262K | ReasoningToolsVisionOpen weights |
| 18 | gpt-oss-120b OpenAI | $0.070 | $0.037 | $0.170 | 131K | ReasoningToolsOpen weights |
| 19 | DeepSeek V4 Flash 0423 DeepSeek | $0.107 | $0.086 | $0.171 | 1.0M | ReasoningToolsOpen weights |
| 20 | Ling 3.0 Flash VL inclusionAI | $0.090 | $0.060 | $0.180 | 131K | Free tierReasoningToolsVisionOpen weights |
| 21 | Ling 3.0 Flash Fin inclusionAI | $0.090 | $0.060 | $0.180 | 262K | Free tierReasoningTools |
| 22 | Laguna S 2.1 Poolside | $0.113 | $0.090 | $0.180 | 1.0M | Free tierReasoningToolsOpen weights |
| 23 | $0.125 | $0.100 | $0.200 | 1.0M | ReasoningToolsVision | |
| 24 | $0.125 | $0.100 | $0.200 | 1.0M | ReasoningToolsVision | |
| 25 | Nemotron 3.5 Lightning NVIDIA | $0.110 | $0.080 | $0.200 | 262K | Free tierReasoningToolsOpen weights |
Frequently asked
What is the cheapest LLM for step-by-step reasoning?
inclusionAI: Ling 3.0 Flash at $0.021 per million input tokens and $0.063 per million output tokens, with a 262K token context window.
How many models qualify for step-by-step reasoning?
218 of the 340 models tracked here meet the criteria for this list.
How much do prices vary within this category?
By roughly 8,300×, from Ling 3.0 Flash at the bottom to o1-pro at the top.