TokenCost.io
Head-to-Head Model Pricing & Benchmark Breakdown

DeepSeek V4 Pro vs GPT-5.6 Terra: Frontier Reasoning Cost & Performance Comparison

Evaluate token savings, mathematical benchmark parity, and 1M context chain-of-thought pricing.

Adjust Your Custom Token Workload

290M tokens/mo
Monthly Requests50k
Input Tokens / Req4000
Output Tokens / Req1800
Prompt Cache %50%

DeepSeek V4 Pro is 81.1% More Cost-Effective

Saves $1,079.20 per month ($12,950.40/yr) at this volume.

Annualized Savings$12,950.40
DeepSeek

DeepSeek V4 Pro

Most Economical
Total Monthly Cost
$250.80 / month
$5.02 per 1,000 requests
Input Tokens / 1M:$0.66
Cached Input / 1M:$0.066
Output Tokens / 1M:$1.98
Context Window:1M
Inference Speed:~75 TPS
Get DeepSeek V4 Pro API Keys
OpenAI

GPT-5.6 Terra

Total Monthly Cost
$1,330.00 / month
$26.60 per 1,000 requests
Input Tokens / 1M:$2.00
Cached Input / 1M:$0.500
Output Tokens / 1M:$12.00
Context Window:1.1M
Inference Speed:~70 TPS
Get GPT-5.6 Terra API Keys

The Verdict: Which Model Wins on Cost & ROI?

DeepSeek V4 Pro delivers frontier reasoning at a 67% discount on input ($0.66 vs $2.00) and 83% discount on output ($1.98 vs $12.00) with 1M context window, making it the most cost-effective reasoning engine in production.

Key Architectural & Economic Differences

  • DeepSeek V4 Pro input is 3x cheaper ($0.66/1M vs $2.00/1M for GPT-5.6 Terra).
  • DeepSeek V4 Pro output is 6x cheaper ($1.98/1M vs $12.00/1M for GPT-5.6 Terra).
  • Both feature 1,000,000+ token context windows.
  • DeepSeek V4 Pro provides a 90% prompt caching discount ($0.066/1M cached input).

When to Choose DeepSeek V4 Pro

  • High-scale reasoning tasks on a startup or production SaaS budget
  • Automated theorem proving, algorithmic problem solving, and math tutoring
  • Cost-conscious developer agent workflows requiring 1M context

When to Choose GPT-5.6 Terra

  • Enterprise security auditing and formal vulnerability verification
  • Longest chain-of-thought generations requiring up to 100,000 output tokens
  • OpenAI platform integrated workflows with strict US enterprise SLAs

Detailed Spec & Pricing Comparison Table

Specification / Metric DeepSeek V4 Pro (DeepSeek) GPT-5.6 Terra (OpenAI) Advantage
Input Price / 1M Tokens $0.66 $2.00 DeepSeek V4 Pro
Cached Input Price / 1M $0.066 (90%) $0.500 (75%) DeepSeek V4 Pro
Output Price / 1M Tokens $1.98 $12.00 DeepSeek V4 Pro
Context Window 1M 1.1M GPT-5.6 Terra
Inference Speed (Tokens/Sec) ~75 TPS ~70 TPS DeepSeek V4 Pro
MMLU Benchmark Score 94.1% 95% GPT-5.6 Terra

Frequently Asked Questions

For a workload generating 50,000 reasoning requests monthly (each with 4,000 input tokens and 2,000 output tokens), GPT-5.6 Terra costs approximately $1,600/month, whereas DeepSeek V4 Pro costs around $330/month—a massive 79.4% reduction.

Related Model Comparisons