|
| 1 | +--- |
| 2 | +title: 'Fine-tuning cost management' |
| 3 | +titleSuffix: Azure OpenAI |
| 4 | +description: Learn about the training and hosting costs associated with fine-tuning |
| 5 | +manager: nitinme |
| 6 | +ms.service: azure-ai-openai |
| 7 | +ms.topic: how-to |
| 8 | +ms.date: 07/08/2025 |
| 9 | +author: mrbullwinkle |
| 10 | +ms.author: mbullwin |
| 11 | +show_latex: true |
| 12 | +--- |
| 13 | + |
| 14 | +# Cost management for fine-tuning |
| 15 | + |
| 16 | +Fine-tuning can be intimidating: unlike base models, where you're just paying for input and output tokens for inferencing, fine-tuning requires training your custom models and dealing with hosting. This guide is intended to help you better understand the costs associated with fine-tuning and how to manage them. |
| 17 | + |
| 18 | +> [!IMPORTANT] |
| 19 | +> The numbers in this article are for example purposes only. You should always refer to the official [pricing page](https://azure.microsoft.com/pricing/details/cognitive-services/openai-service) for pricing details to use in the formulas provided in this article. |
| 20 | +
|
| 21 | +## Upfront investment - training your model |
| 22 | + |
| 23 | +This is the one-time, fixed cost associated with teaching a base model your specific requirements using your training data. |
| 24 | + |
| 25 | +### The calculation formula |
| 26 | + |
| 27 | +**Supervised Fine-Tuning (SFT) & Preference Fine-Tuning (DPO)** |
| 28 | + |
| 29 | +It's straightforward to estimate the costs for SFT & DPO. You're charged based on the number of tokens in your training file, and the number of epochs for your training job. |
| 30 | + |
| 31 | +$$ |
| 32 | +\text{price} = \text{\# training tokens} \times \text{\# epochs} \times \text{price per token} |
| 33 | +$$ |
| 34 | + |
| 35 | +In general, smaller models and more recent models have lower prices per token than larger, older models. To estimate the number of tokens in your file, you can use the [tiktoken library](https://github.com/openai/tiktoken) – or, for a less precise estimate, one word is roughly equivalent to four tokens. |
| 36 | + |
| 37 | +We offer both regional and global training for SFT; if you don't need data residency, global training allows you to train at a discounted rate. |
| 38 | + |
| 39 | +> [!IMPORTANT] |
| 40 | +> We don't charge you for time spent in queue, failed jobs, jobs canceled prior to training beginning, or data safety checks. |
| 41 | +
|
| 42 | +#### Example: Supervised fine-tuning (SFT) |
| 43 | + |
| 44 | +Projecting the hypothetical costs to fine-tune a model that takes natural language and outputs code. |
| 45 | + |
| 46 | +1. Prepare the training data file: 500 prompt / response pairs, with a total of 1 million tokens, and a validation file with 20 examples and 40,000 tokens. |
| 47 | +2. Configure training run: |
| 48 | + - Select base model (GPT-4.1) |
| 49 | + - Specify global training |
| 50 | + - Set hyperparameters to **default**. Algorithmically, training is set to 2 epochs. |
| 51 | + |
| 52 | +Training runs for 2 hours, 15 minutes |
| 53 | + |
| 54 | +**Total cost**: |
| 55 | + |
| 56 | +$$ |
| 57 | +\$2 \div 1\text{M tokens} \times 1\text{M training tokens} \times 2\text{ epochs} = \$4 |
| 58 | +$$ |
| 59 | + |
| 60 | +### Reinforcement fine-tuning (RFT) |
| 61 | + |
| 62 | +The cost is determined by the time spent on training the model for Reinforcement fine tuning technique. |
| 63 | + |
| 64 | +**The formula is:** |
| 65 | + |
| 66 | +$$ |
| 67 | +\text{price} = \text{Time taken for training} \times \text{Hourly training cost} + \text{Grader inferencing per token (if model grader is used)} |
| 68 | +$$ |
| 69 | + |
| 70 | +- **Time**: Total time in hours rounded to two decimal places (for example, 1.25 hours). |
| 71 | +- **Hourly Training cost**: $100 per hour of core training time for `o4-mini-2025-04-16`. Refer to the [pricing page](https://azure.microsoft.com/pricing/details/cognitive-services/openai-service) for actual pricing details. |
| 72 | +- **Model grading**: Tokens used to grade outputs during training are billed separately at data zone rates once training is complete. |
| 73 | + |
| 74 | +#### Example: Training model with graders (without Model grader – Score_model) |
| 75 | + |
| 76 | +Let's project the cost to train a customer service chatbot. |
| 77 | + |
| 78 | +- Submit fine-tuning job: Time when the fine-tuning job was submitted: 02:00 hrs |
| 79 | +- Data preprocessing completed: It took 30 minutes for data preprocessing to be completed which includes data safety checks. This time isn't used for billing. |
| 80 | +- Training started: Training starts at 02:30 hours |
| 81 | +- Training completed: Training is completed at 06:30 hours |
| 82 | +- Model creation: A deployable model checkpoint is created after training completion, which included post-training model safety steps. This time isn't used for billing. |
| 83 | + |
| 84 | +**Final Calculation**: |
| 85 | + |
| 86 | +$$ |
| 87 | +\text{Total time taken for training} \times \text{Hourly training cost} = 4 \times 100 = \$200 |
| 88 | +$$ |
| 89 | + |
| 90 | +Your one-time investment to create this `o4-mini` custom fine tuned model would be **$400.00**. |
| 91 | + |
| 92 | +#### Example: Training a model with Model ‘Score_model’ grader (o3-mini being used as grader) |
| 93 | + |
| 94 | +Let's project the cost to train a customer service chatbot. |
| 95 | + |
| 96 | +- Submit fine tuning job: Time when FT job has started say 02:00 hrs |
| 97 | +- Data preprocessing completed: It took 30 minutes for data preprocessing to be completed which includes data safety checks. This time isn't used for billing. |
| 98 | +- Training started: Training starts at 02:30 hours |
| 99 | +- Training completed: Training is completed at 06:30 hours |
| 100 | +- Model grader pricing: |
| 101 | + - Total Input tokens used for grading – 5 million tokens |
| 102 | + - Total Output tokens used for grading – 4.9 million tokens |
| 103 | +- Model creation: A deployable model checkpoint is created after training completion, which included post-training model safety steps. This time isn't used for billing. |
| 104 | + |
| 105 | +**Final Calculation**: |
| 106 | + |
| 107 | +$$ |
| 108 | +\text{Total time taken for training} \times \text{Hourly training cost} = 4 \times 100 = \$400 |
| 109 | +$$ |
| 110 | + |
| 111 | +$$ |
| 112 | +\text{Grading costs} = \text{\# Input tokens} \times \text{Price per input token} + \text{Output tokens} \times \text{Price per output token} |
| 113 | +$$ |
| 114 | + |
| 115 | +$$ |
| 116 | += (5 \times 1.1) + (4.9 \times 4.4) = 5.5 + 21.56 = \$27.06 |
| 117 | +$$ |
| 118 | + |
| 119 | +$$ |
| 120 | +\text{Total training costs} = \$427.06 |
| 121 | +$$ |
| 122 | + |
| 123 | +Your one-time investment to create this o4-mini custom fine tuned model would be **$427.06** |
| 124 | + |
| 125 | +### Managing costs and spending limits when using RFT |
| 126 | + |
| 127 | +To control your spending, we recommend: |
| 128 | + |
| 129 | +- Start with shorter runs to understand how your configuration affects time – Use configuration `reasoning effort` – Low, smaller validation data sets |
| 130 | +- Use a reasonable number of validation examples and `eval_samples`. Avoid validating more often than you need. |
| 131 | +- Choose the smallest grader model that meets your quality requirements. |
| 132 | +- Adjust `compute_multiplier` to balance convergence speed and cost. |
| 133 | +- Monitor your run in the Foundry portal or via the API. You can pause or cancel at any time. |
| 134 | + |
| 135 | +As RFT jobs can lead to high training costs, we're capping the pricing for per training job billing to **$5000** which means this will be the maximum amount that a job can cost before we end the job. The training will be paused and a deployable checkpoint will be created. Users can validate the training job, metrics, logs and then decide to resume the job to complete further. If the user decides to resume the job, billing will continue for the job and subsequently no further price limits would be placed on the training job. |
| 136 | + |
| 137 | +### Job failures and cancellations |
| 138 | + |
| 139 | +You aren't billed for work lost due to our error. However, if you cancel a run, you'll be charged for the work completed up to that point. |
| 140 | + |
| 141 | +**Example**: the run trains for 2 hours, writes a checkpoint, trains for 1 more hour, but then fails. Only the 2 hours of training up to the checkpoint are billable. |
| 142 | + |
| 143 | +## Ongoing operational costs – using your model |
| 144 | + |
| 145 | +After your model is trained, you can deploy it any number of times using the following deployment types: |
| 146 | + |
| 147 | +We have three options for hosting: |
| 148 | + |
| 149 | +- **Standard**: pay per-token at the same rate as base model Standard deployments with an additional $1.70/hour hosting fee. Offers regional data residency guarantees. |
| 150 | +- **Global Standard**: pay per-token at the same rate as base model Global Standard deployments with an additional hosting fee. Doesn't offer data residency guarantees. Offers higher throughput than Standard deployments. |
| 151 | +- **Regional Provisioned Throughput**: offers latency guarantees, designed for latency-sensitive workloads. Instead of paying per-token or an hourly hosting fee, deployments accrue PTU-hours based on the number of provisioned throughput units (PTU) assigned to the deployment, and billed at a rate determined by your agreements or reservations with Microsoft Azure. |
| 152 | +- **Developer Tier (Public Preview)**: pay per-token and without an hourly hosting fee but offers neither data residency nor availability guarantees. Developer Tier is designed for model candidate evaluation and proof of concepts, deployments are removed automatically after 24 hours regardless of usage but may be redeployed as needed. |
| 153 | + |
| 154 | +The right deployment type for your use case depends on weighing your AI requirements and where you are on your fine-tuning journey. |
| 155 | + |
| 156 | +| Deployment Type | Availability | Latency | Token Rate | Hourly Rate | |
| 157 | +|----------------------------|------------------|-------------|--------------------|-----------------| |
| 158 | +| Standard | [SLA](https://www.microsoft.com/licensing/docs/view/Service-Level-Agreements-SLA-for-Online-Services) | - | Same as base model | $1.70/hour | |
| 159 | +| Global Standard | [SLA](https://www.microsoft.com/licensing/docs/view/Service-Level-Agreements-SLA-for-Online-Services) | - | Same as base model | $1.70/hour | |
| 160 | +| Regional Provisioned Throughput | [SLA](https://www.microsoft.com/licensing/docs/view/Service-Level-Agreements-SLA-for-Online-Services) | [PTU](/azure/ai-foundry/openai/concepts/provisioned-throughput?tabs=global-ptum#when-to-use-provisioned-throughput) | None | PTU/hour | |
| 161 | +| Developer Tier | None | - | Same as Global Standard | None | |
| 162 | + |
| 163 | +Full pricing information for all models is available on the [Azure OpenAI pricing page](https://azure.microsoft.com/pricing/details/cognitive-services/openai-service). |
| 164 | + |
| 165 | +### Example for o4-mini |
| 166 | + |
| 167 | +- Hosting charges: $1.70 per hour |
| 168 | +- Input Cost: $1.10 per 1M tokens |
| 169 | +- Output Cost: $4.40 per 1M tokens |
| 170 | + |
| 171 | +#### Example: Monthly Usage of a Fine-Tuned Chatbot |
| 172 | + |
| 173 | +Let's assume your chatbot handles 10,000 customer conversations in its first month: |
| 174 | + |
| 175 | +- Hosting charges: $1.70 per hour |
| 176 | +- Total Input: The user queries sent to the model total 20 million tokens. |
| 177 | +- Total Output: The model's responses to users total 40 million tokens. |
| 178 | +- Input Cost Calculation: 20× $1.10 = $22.00 |
| 179 | +- Output Cost Calculation: 40 × $4.40 = $176.00 |
| 180 | + |
| 181 | +Your total operational cost for the month would be: |
| 182 | + |
| 183 | +Total Cost = Hosting charges + Token usage cost |
| 184 | + |
| 185 | +$$ |
| 186 | +\text{Total Cost} = (1.70 \times 30 \times 24) + (22 + 176) = \$1422.00 |
| 187 | +$$ |
| 188 | + |
| 189 | +Always refer to the [pricing page](https://azure.microsoft.com/pricing/details/cognitive-services/openai-service) for pricing information. The numbers in this article are for example purposes only. |
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