# Phi-4

Phi-4 is a text generation model from Microsoft, available through the Impossibl API. Its published context window is 16,000 tokens. The advertised input rate is $0.125 per million input tokens. The advertised output rate is $0.50 per million output tokens.

- Model identifier: ` microsoft/phi-4 `
- Creator: Microsoft
- Model type: Text generation
- Canonical model page: [Phi-4](<https://impossibl.com/microsoft/phi-4>)
- API availability: Listed as serving through Impossibl.
- Creator release date: 2024-12-12

## Capabilities and limits

- Context window: 16,000 tokens
- Maximum output tokens: Not published in the public catalog; this is separate from the context window.
- Inputs: text
- Outputs: text
- Tool calling: Not supported

## API access

Use ` microsoft/phi-4 ` as the model identifier through the Impossibl API.

Published API endpoints:

- ` /v1/chat/completions `

[API quickstart](<https://impossibl.com/docs/agent-quickstart>) · [Models and billing documentation](<https://impossibl.com/docs/models>)

## Published API prices

All rates are in USD. An unpublished rate is unknown, not zero. Workspace-specific pricing, taxes, balance-purchase fees, billing adjustments, and tool charges can affect the amount paid.

| Usage | Published base rate | Billing unit |
| --- | --- | --- |
| Input | $0.125 | per million input tokens |
| Output | $0.50 | per million output tokens |
| Cache read | Not published | per million cached input tokens |
| Cache write (default retention) | Not published | per million tokens |
| Cache write (one-hour retention) | Not published | per million tokens |
| Audio input | Not published | per million audio input tokens |

## Independent benchmarks

Source: [Artificial Analysis](<https://artificialanalysis.ai/>). Last checked: 2026-09-11T11:52:20.926Z.
Configurations are evaluated separately. API scores retain their original units. Unmeasured scores are omitted.

### Phi-4

Source: [Evaluation source](<https://artificialanalysis.ai/models/phi-4>)

| Benchmark | Score |
| --- | --- |
| Intelligence Index | 5.92 |
| Omniscience Index | -55.70 |
| GPQA | 57.47% |
| Humanity’s Last Exam | 3.76% |
| CritPt | 0.00% |
| Terminal-Bench Hard | 3.79% |
| AA-LCR | 0.00% |
| IFBench | 23.54% |
| Tau2 | 0.00% |
| LiveCodeBench | 23.07% |
| AIME 2025 | 18.00% |
| intelligence index (API) | 5.9 |

Full benchmark data and breakdowns: [Complete benchmark snapshot](<https://api.impossibl.com/v1/models/microsoft/phi-4/benchmarks>).


## Availability and retirement

The model is listed as serving. No retirement is announced in the current public catalog.

## Frequently asked questions

### What is Phi-4?

Phi-4 is a text-generation model from Microsoft, available through the Impossibl API.

### How much does Phi-4 cost?

Phi-4 costs $0.125 per million input tokens and $0.50 per million output tokens through the Impossibl API. All rates are in USD.

### What is the context length of Phi-4?

Phi-4 has a 16,000-token context window through the Impossibl API.

### Does Phi-4 support tool calling?

No. Phi-4 does not support tool calling through the Impossibl API.

### What inputs and outputs does Phi-4 support?

Phi-4 accepts text as input. Phi-4 returns text.

### How do I use Phi-4 through an API?

Phi-4 is available through the Impossibl API. Use microsoft/phi-4 as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

### When was Phi-4 released?

Microsoft released Phi-4 on December 12, 2024.

Sources: [Creator release announcement](<https://techcommunity.microsoft.com/blog/aiplatformblog/introducing-phi-4-microsoft%E2%80%99s-newest-small-language-model-specializing-in-comple/4357090>)

## Sources and related links

Prices, limits, capabilities, endpoints, and availability come from the public Impossibl catalog. Creator documentation supplies descriptions and release dates where available; it does not override the published API offering.

- [Public Impossibl model catalog](<https://api.impossibl.com/v1/models>)
- [Full model directory as JSON](<https://impossibl.com/models.json>)
- [Phi-4: model details and pricing](<https://impossibl.com/microsoft/phi-4>)
- [Model directory](<https://impossibl.com/models>)