Last verified 2026-03-12 (left) · 2026-04-24 (right)

DeepSeek Reasoner vs GPT-5.5 Pro — Pricing & Capability Comparison

DeepSeek Reasoner charges $0.55 per million input tokens and $2.19 per million output tokens. GPT-5.5 Pro comes in at $30.00 / $180.00. Context windows span 64K vs 1M tokens respectively.

TL;DR — Quick Comparison

✓DeepSeek Reasoner is cheaper overall: $2.74 per 1M tokens (in+out) vs $210.00 for GPT-5.5 Pro — saves $207.26 per 1M tokens
✓Input pricing: DeepSeek Reasoner $0.55/1M vs GPT-5.5 Pro $30.00/1M
✓Output pricing: DeepSeek Reasoner $2.19/1M vs GPT-5.5 Pro $180.00/1M
✓Context window: GPT-5.5 Pro offers more (1M vs 64K)
✓Use our calculator below to estimate costs for your specific usage pattern

Input price (per 1M)

DeepSeek Reasoner

$0.55

GPT-5.5 Pro

$30.00

DeepSeek Reasoner leads here

Output price (per 1M)

DeepSeek Reasoner

$2.19

GPT-5.5 Pro

$180.00

DeepSeek Reasoner leads here

Context window

DeepSeek Reasoner

64,000 tokens

GPT-5.5 Pro

1,000,000 tokens

GPT-5.5 Pro leads here

Cached input

DeepSeek Reasoner

$0.140

GPT-5.5 Pro

Not published

DeepSeek Reasoner leads here

Which one should you choose?

Skip the spreadsheet if you just need the practical takeaway. Use these rules when deciding between DeepSeek Reasoner and GPT-5.5 Pro.

Choose DeepSeek Reasoner if input tokens dominate your bill

DeepSeek Reasoner has the lower input rate, which usually matters most for chat, RAG, classification, and long-prompt workflows where prompt volume stays much larger than generated output.

Choose DeepSeek Reasoner if you generate long answers

DeepSeek Reasoner is cheaper on output tokens, so it tends to win for report generation, coding assistance, reasoning traces, and any workflow where completions are long.

Choose GPT-5.5 Pro if context size is the blocker

GPT-5.5 Pro offers the larger published context window, which is more important than small pricing differences when you need to fit large files, long chats, or multi-document prompts into one request.

Cost comparison for 10K-token workloads

Side-by-side pricing for identical workloads (10,000 total tokens per request) across different distributions.

Scenario	DeepSeek Reasoner	GPT-5.5 Pro	DeepSeek Reasoner cached
Balanced conversation 50% input · 50% output	$0.0137	$1.05	$0.0117
Input-heavy workflow 80% input · 20% output	$0.0088	$0.600	$0.0055
Generation heavy 30% input · 70% output	$0.0170	$1.35	$0.0158
Cached system prompt 90% cached input · 10% fresh output	$0.0071	$0.450	$0.0034

Frequently asked questions

Which is cheaper: DeepSeek Reasoner or GPT-5.5 Pro?

DeepSeek Reasoner is cheaper for input tokens at $0.55 per 1M tokens compared to $30.00. For output, DeepSeek Reasoner costs $2.19 per 1M tokens versus $180.00 for GPT-5.5 Pro.

What is the cost per 1M tokens for DeepSeek Reasoner?

DeepSeek Reasoner pricing: $0.55 per 1M input tokens and $2.19 per 1M output tokens. Context window: 64,000 tokens.

What is the cost per 1M tokens for GPT-5.5 Pro?

GPT-5.5 Pro pricing: $30.00 per 1M input tokens and $180.00 per 1M output tokens. Context window: 1,000,000 tokens.

How much does it cost per 1K tokens?

Per 1K tokens: DeepSeek Reasoner costs $0.0006 input / $0.0022 output. GPT-5.5 Pro costs $0.0300 input / $0.1800 output. This is useful for calculating small-scale usage costs.

Which model supports a larger context window?

GPT-5.5 Pro offers 1,000,000 tokens (1M) versus 64K for DeepSeek Reasoner.

What is the estimated monthly cost for typical usage?

For a typical workload of 10M input + 2M output tokens per month: DeepSeek Reasoner would cost approximately $9.88, while GPT-5.5 Pro would cost $660.00. DeepSeek Reasoner is more economical for this usage pattern.

Do these models support prompt caching?

DeepSeek Reasoner supports prompt caching at $0.140 per 1M cached tokens, reducing costs for repeated context by up to 75%. GPT-5.5 Pro does not publish cached pricing.

Which model is best for my use case?

Choose DeepSeek Reasoner for cost-sensitive applications with high input volume. Choose GPT-5.5 Pro if you need 1M context for long documents or conversations. Consider prompt caching if you have repeated context. Use our token calculator to model your specific usage pattern.