LLMmicrosoft

Microsoft: Phi 4

[Microsoft Research](/microsoft) Phi-4 is designed to perform well in complex reasoning tasks and can operate efficiently in situations with limited memory or where quick responses are needed. At 14 billion...

Anyone in the Project can @-mention Microsoft: Phi 4 with the team's shared context - pooled credits, one chat, one memory.

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Verdict

Phi 4 delivers surprisingly strong reasoning for its 14B parameter size, punching above its weight class on math and coding tasks while keeping costs low. The 16K context window limits its use for long documents, and it trails frontier models on nuanced instruction-following. Reach for this when you need fast, cost-effective inference for structured problems where context fits comfortably under 16K tokens.

Best for

  • Math problem solving under budget constraints
  • Code generation for short functions
  • Structured reasoning tasks with tight context
  • High-throughput inference pipelines
  • Prototyping before scaling to larger models

Strengths

Phi 4's 14B parameters achieve reasoning performance that rivals models 3-5x its size, making it exceptionally cost-effective at $0.07/$0.14 per Mtok. Microsoft optimized this model specifically for STEM tasks, and it shows: math word problems and algorithmic reasoning benefit from training on synthetic data that emphasizes logical chains. Inference speed is a practical advantage — smaller parameter count means lower latency and easier self-hosting for teams that need on-premise deployment.

Trade-offs

The 16K context window becomes a bottleneck fast when analyzing multi-file codebases or long documents — you'll hit limits where Claude or GPT-4 keep going. Phi 4 also struggles with ambiguous instructions and creative writing compared to frontier models; it's tuned for precision over flexibility. Expect weaker performance on multilingual tasks and nuanced tone control. The proprietary license restricts commercial fine-tuning, so you're locked into Microsoft's weights as-is.

Specifications

Provider
microsoft
Category
llm
Context length
16,384 tokens
Max output
14,745 tokens
Modalities
text
License
proprietary
Released
2025-01-10

Pricing

Input
$0.07/Mtok
Output
$0.14/Mtok
Model ID
microsoft/phi-4

Per-token prices show what the model costs upstream. On Switchy your team draws from one shared org credit pool - one plan, one balance for everyone.

Team cost calculator

Estimated monthly spend
$1.60
17.6M tokens / month
5 seats · 80 msgs/day

Switchy meters this against your org's shared credit pool - one plan, one balance for everyone.

Providers

ProviderContextInputOutputP50 latencyThroughput30d uptime
microsoft16k$0.07/Mtok$0.14/Mtok———

Performance

Performance snapshots are collected daily. Check back after the next ingestion run.

Benchmarks

Public benchmark scores are not available yet for this model. Check back after the next ingestion run.

Works well with

Top MCPs

Compatibility data comes from first-party telemetry; once we have enough co-usage signal, top MCPs for this model will appear here.

How Switchy teams use it

Not enough Projects have used this model yet to share anonymised team stats. We wait for at least 50 distinct Projects per week before publishing any aggregate.

Starter prompts

Solve Multi-Step Math Problem

Solve this problem step-by-step, showing your work at each stage: A train travels 240 miles in 4 hours, then increases speed by 20% for the next 3 hours. What is the total distance traveled?

Generate Python Function

Write a Python function that takes a list of integers and returns the longest consecutive sequence. Include docstring and handle edge cases like empty lists.

Debug Code Snippet

Find and explain the bug in this code: ```python
def find_max(nums):
    max_val = 0
    for n in nums:
        if n > max_val:
            max_val = n
    return max_val
```

Explain Algorithm Complexity

Analyze the time and space complexity of this sorting approach: repeatedly find the minimum element in the unsorted portion and swap it to the front. Explain your reasoning.

Convert Natural Language to SQL

Write a SQL query for this request: Find all customers who placed more than 3 orders in the last 6 months and have a total order value exceeding $500. Tables: customers(id, name), orders(id, customer_id, order_date, total).

Example outputs

Illustrative - representative of the model's voice and quality, not literal recordings.

Prompt

Review this Python function for edge cases and suggest improvements: def calculate_discount(price, discount_percent): return price - (price * discount_percent / 100)

Output

The function has several edge cases to handle: 1. **Negative values**: No validation for negative price or discount_percent 2. **Discount > 100%**: Could return negative final price 3. **Type safety**: No checks for non-numeric inputs Improved version: ```python def calculate_discount(price: float, discount_percent: float) -> float: if price < 0: raise ValueError("Price cannot be negative") if not 0 <= discount_percent <= 100: raise ValueError("Discount must be between 0 and 100") return price * (1 - discount_percent / 100) ``` The refactored calculation `price * (1 - discount_percent / 100)` is also more numerically stable for floating-point arithmetic.

Notes

Phi 4's 14B parameter size delivers solid code review with practical edge-case identification. The 16K context window handles this single-function review easily, though larger codebases would require chunking. At $0.07/$0.14 per Mtok, this is cost-effective for iterative code review workflows where you need multiple passes.

Prompt

Explain the difference between TCP and UDP to a junior developer who understands basic networking but hasn't worked with protocols directly.

Output

Think of TCP and UDP as two different shipping services: **TCP (Transmission Control Protocol)** is like certified mail with tracking. It guarantees your package arrives, in order, and confirms delivery. If something goes wrong, it resends. This reliability comes with overhead—handshakes, acknowledgments, retransmissions. Use TCP for web browsing, file transfers, emails—anything where accuracy matters more than speed. **UDP (User Datagram Protocol)** is like throwing postcards in the mail. Fast, lightweight, no guarantees. Packets might arrive out of order, get lost, or duplicate. But there's minimal overhead. Use UDP for live video, gaming, DNS lookups—anything where speed matters and you can tolerate occasional data loss. Rule of thumb: Need reliability? TCP. Need speed and can handle imperfection? UDP.

Notes

This example shows Phi 4's ability to adapt technical explanations to audience level—the shipping analogy makes protocols concrete without oversimplifying. The model balances accessibility with technical accuracy. However, at 16K tokens, extended back-and-forth tutoring sessions may hit context limits faster than larger-window alternatives.

Prompt

Generate a SQL query to find customers who made purchases in Q1 2024 but not in Q2 2024, including their total Q1 spend. Tables: customers (id, name), orders (id, customer_id, order_date, amount).

Output

```sql SELECT c.id, c.name, SUM(o.amount) AS q1_total_spend FROM customers c INNER JOIN orders o ON c.id = o.customer_id WHERE o.order_date >= '2024-01-01' AND o.order_date < '2024-04-01' AND c.id NOT IN ( SELECT DISTINCT customer_id FROM orders WHERE order_date >= '2024-04-01' AND order_date < '2024-07-01' ) GROUP BY c.id, c.name ORDER BY q1_total_spend DESC; ``` This uses a subquery to exclude Q2 purchasers. For large datasets, consider a LEFT JOIN with NULL check instead of NOT IN for better performance.

Notes

Phi 4 generates syntactically correct SQL with appropriate date filtering and aggregation. The performance note shows awareness of query optimization. The 16K context window accommodates schema descriptions and multi-table queries comfortably, though complex data warehouse schemas with dozens of tables would strain it. Pricing makes this viable for automated query generation in internal tools.

Use-case deep-dives

Budget-constrained prototyping sprints

Why Phi 4 works for rapid iteration on tight budgets

A 4-person product team building an MVP chatbot needs to test 20 prompt variations daily without burning through their $200/month AI budget. Phi 4 at $0.07/$0.14 per Mtok is roughly 10x cheaper than frontier models, which means they can run 500k input tokens and 250k output tokens for under $50. The 16k context window handles most conversational threads and product docs without chunking. The trade-off: you'll hit quality ceilings on complex reasoning or nuanced tone—if user testing shows the bot missing intent more than 15% of the time, budget up to GPT-4o mini. For prototyping where speed and cost matter more than perfection, Phi 4 lets you fail fast and iterate without the invoice anxiety.

Internal FAQ automation

When Phi 4 handles repetitive support queries at scale

A 30-person SaaS company fields 200 internal Slack questions daily about PTO policy, expense rules, and onboarding steps. Phi 4 can ingest the 12k-token employee handbook, match questions to sections, and draft answers in under 2 seconds at $0.07 input per million tokens. Over a month, that's roughly 6M input tokens ($0.42) and 3M output tokens ($0.42)—under a dollar for thousands of responses. The 16k window fits the full handbook plus conversation history, so answers stay contextual across follow-ups. The boundary: if questions require interpreting ambiguous policy edge cases or synthesizing across multiple documents, accuracy drops and you'll need a larger model. For straightforward lookup-and-paraphrase tasks where the answer exists in a single doc, Phi 4 delivers at a price that makes automation a no-brainer.

High-frequency content moderation

Phi 4 for real-time comment filtering on community platforms

A 10-person ed-tech startup runs a student forum with 5,000 comments posted daily and needs to flag spam, profanity, and off-topic posts before they go live. Phi 4's sub-$0.10/Mtok combined pricing means scanning 500 tokens per comment (2.5M tokens/day input, 500k tokens/day output for verdicts) costs around $0.25 daily or $7.50/month. The 16k context window lets you include community guidelines and recent thread context in each moderation call. The catch: Phi 4 will miss subtle harassment patterns or sarcasm that frontier models catch—if your false-negative rate climbs above 5%, you need a smarter model or human review layer. For high-volume, low-stakes filtering where speed and cost are the constraints, Phi 4 keeps the workflow moving without the per-call sticker shock.

Frequently asked

Is Phi 4 good for general text tasks?

Phi 4 handles everyday text tasks like summarization, Q&A, and basic reasoning well for a small language model. It's designed for efficiency over raw capability, so it works for straightforward prompts but struggles with complex multi-step reasoning or specialized domains. If you need consistent performance across edge cases, larger models like GPT-4o or Claude will be more reliable.

Is Phi 4 cheaper than GPT-4o or Claude?

Yes, significantly. At $0.07 input and $0.14 output per million tokens, Phi 4 costs roughly 10-20x less than frontier models. The trade-off is capability—you're paying less because it's a smaller model with narrower knowledge and weaker reasoning. For high-volume, low-complexity tasks where cost matters more than perfection, the savings add up fast.

Can Phi 4 handle 16K token contexts reliably?

The 16K context window is functional but not exceptional by 2025 standards. It's enough for medium-length documents or conversations, but you'll hit limits with large codebases or multi-document analysis. Performance can degrade toward the end of the context window, especially for retrieval tasks. If you routinely work with 50+ page documents, look at models with 100K+ windows.

How does Phi 4 compare to Phi 3.5?

Without public benchmarks, we can't quantify the improvement, but Microsoft typically iterates on instruction-following and safety in Phi updates. Expect modest gains in accuracy and coherence, not a capability leap. If Phi 3.5 worked for your use case, Phi 4 will likely work slightly better. If Phi 3.5 failed, Phi 4 probably won't fix it—consider a larger model instead.

Should I use Phi 4 for production chatbots?

Only if your chatbot handles narrow, well-defined tasks and you've tested it thoroughly. Phi 4's small size means it's fast and cheap, but it's more prone to hallucinations and off-topic responses than larger models. For customer-facing applications where mistakes are costly, the savings aren't worth the risk. For internal tools or prototypes, it's a reasonable starting point.

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Data last verified 13 hours ago.Sources aggregated hourly to weekly. See docs/architecture/model-directory.md.