DeepSeek V4 Flash vs GPT-5.5 Pro: API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for DeepSeek V4 Flash (DeepSeek) and GPT-5.5 Pro (OpenAI). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.
Prices verified Apr 30, 2026
Interactive Cost Calculator
Fills in typical token counts for a workload type
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Total API calls per month
Showing costs for 2 models. Cheapest: DeepSeek V4 Flash at $2.80/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestDeepSeek V4 Flash | DeepSeek | $2.80 | $0.000280 | $1.40 | $1.40 | 99.8% | Alerts coming soon |
GPT-5.5 Pro | OpenAI | $1,200.00 | $0.120000 | $300.00 | $900.00 | — | Alerts coming soon |
Monthly Cost Comparison
Price Comparison at a Glance
All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.
| Pricing Type | DeepSeek V4 Flash | GPT-5.5 Pro | Cheaper |
|---|---|---|---|
| Input (standard) | $0.14/M | $30.00/M | DeepSeek V4 Flash |
| Output | $0.28/M | $180.00/M | DeepSeek V4 Flash |
Prices last verified: 2026-04-30
Cost Breakdown by Usage Volume
Estimated monthly costs at different request volumes, assuming 1,000 input tokens and 500 output tokens per request. Adjust in the calculator above for your specific use case.
| Volume | DeepSeek V4 FlashMonthly | GPT-5.5 ProMonthly | DeepSeek V4 FlashPer request | GPT-5.5 ProPer request |
|---|---|---|---|---|
| 1K requests/mo | $0.28 | $120.00 | $0.000280 | $0.120000 |
| 10K requests/mo | $2.80 | $1,200.00 | $0.000280 | $0.120000 |
| 100K requests/mo | $28.00 | $12,000.00 | $0.000280 | $0.120000 |
| 1M requests/mo | $280.00 | $120,000.00 | $0.000280 | $0.120000 |
Green values indicate the lower-cost option at each volume tier. Cost per request is calculated at 1,000 input + 500 output tokens using standard (non-batch, non-cached) pricing.
When to Choose DeepSeek V4 Flash
by DeepSeek
- General chatbot
Input / 1M tokens
$0.14/M
Output / 1M tokens
$0.28/M
Context window
1,048,576
Tier
budget
When to Choose GPT-5.5 Pro
by OpenAI
- General chatbot
Input / 1M tokens
$30.00/M
Output / 1M tokens
$180.00/M
Context window
1,050,000
Tier
premium
Key Differences Beyond Price
Cost is only one factor in choosing an AI model. Context window size, rate limits, supported features, and latency all affect whether a model fits your use case.
| Capability | DeepSeek V4 Flash | GPT-5.5 Pro |
|---|---|---|
| Context window | 1,048,576 tokens | 1,050,000 tokens |
| Max output tokens | 384,000 tokens | 128,000 tokens |
| Performance tier | Budget | Premium |
| Vision / image input | No | Yes |
| Function calling | Yes | Yes |
| JSON mode | Yes | Yes |
| Prompt caching | No | No |
| Batch API (50% discount) | No | No |
| Extended reasoning | Yes | Yes |
| Fine-tuning | No | No |
Frequently Asked Questions
Is DeepSeek V4 Flash cheaper than GPT-5.5 Pro?
At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), DeepSeek V4 Flash costs $28.00/month versus $12,000.00/month for GPT-5.5 Pro — a 100% saving. Your actual savings will vary based on your token profile; output-heavy workloads amplify differences in output pricing.
Which model has a larger context window, DeepSeek V4 Flash or GPT-5.5 Pro?
GPT-5.5 Pro has a larger context window at 1,050,000 tokens, compared to 1,048,576 tokens for DeepSeek V4 Flash. A larger context window is important for processing long documents, multi-turn conversations, or large codebases without truncation.
Do DeepSeek V4 Flash and GPT-5.5 Pro support the Batch API?
Neither DeepSeek V4 Flash nor GPT-5.5 Pro currently supports a batch API with discounted pricing. For batch-eligible alternatives, consider models from OpenAI, Anthropic, or Google that include batch API support.
Which model offers better prompt caching?
Neither DeepSeek V4 Flash nor GPT-5.5 Pro currently supports prompt caching. For prompt-caching capable alternatives, consider Claude models from Anthropic or GPT-4o from OpenAI.
What are the best use cases for DeepSeek V4 Flash vs GPT-5.5 Pro?
Both models are well-suited for General chatbot. DeepSeek V4 Flash is particularly strong for overlapping tasks. GPT-5.5 Pro is favored for similar workflows. At the same quality level, the lower-cost model is usually preferable; use this page's calculator to compare total monthly spend at your volume.
What is the cost per request for DeepSeek V4 Flash vs GPT-5.5 Pro?
At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — DeepSeek V4 Flash costs $0.000280 per request and GPT-5.5 Pro costs $0.120000 per request. At 100,000 requests/month, that translates to $28.00 and $12,000.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
DeepSeek V4 Flash vs GPT-5.5 Pro: Summary
When comparing DeepSeek V4 Flash and GPT-5.5 Pro for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. DeepSeek V4 Flash offers lower total cost at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $28.00/month, compared to $12,000.00/month for GPT-5.5 Pro.
Both models are priced in USD per million tokens, the standard unit across all major AI API providers. DeepSeek V4 Flash charges $0.14/M for input tokens and $0.28/M for output tokens. GPT-5.5 Pro charges $30.00/M input and $180.00/M output. If your workload is output-heavy (more tokens generated than consumed as input), the model with the lower output price compounds cost savings significantly at scale.
Context window capacity differs between the two: GPT-5.5 Pro supports up to 1,050,000 tokens in a single request, versus 1,048,576 tokens for DeepSeek V4 Flash. A larger context window is essential for document summarization, large codebase analysis, and multi-document retrieval-augmented generation (RAG) applications.
Use the interactive calculator at the top of this page to enter your actual token usage and monthly request volume for a precise cost comparison tailored to your workload. Adjust for batch API discounts and prompt caching to find the most cost-effective option for your specific deployment.
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Relevant Use Cases
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