GPT-5 vs DeepSeek-V3: Detailed Comparison

Choosing between GPT-5 (OpenAI) and DeepSeek-V3 (DeepSeek) comes down to three things: per-token pricing, context window, and which capability matters most for your workload. GPT-5 costs $1.25/M input vs $0.27/M for DeepSeek-V3; context windows are 400K vs 128K tokens. Detailed breakdown below.

Side-by-side specs

SpecGPT-5DeepSeek-V3
ProviderOpenAIDeepSeek
Released2025-08-072024-12-26
Input price $1.25/M $0.27/M
Output price $10.00/M $1.10/M
Cached input $0.1300/M $0.0700/M
Context window 400K 128K
Max output 128K 8K
Modalities text image text
Tokenizer o200k_base deepseek

Capability matrix

CapabilityGPT-5DeepSeek-V3
function calling Yes Yes
json mode Yes Yes
vision Yes No
streaming Yes Yes
reasoning Yes No

Benchmark comparison

Higher is better for all benchmarks shown.

BenchmarkCategoryGPT-5DeepSeek-V3Δ
MMLU-Pro general 88.4 75.9 +12.5
GPQA Diamond reasoning 85.7
SWE-bench Verified coding 74.9
AIME 2025 math 94.6
HumanEval coding 82.6

Per-call cost on typical workloads

Workload (in/out tokens)GPT-5DeepSeek-V3Cheaper by
Standard chat (1K / 500) $0.006250 $0.000820 DeepSeek-V3 by $0.005430
RAG (4K / 500) $0.010000 $0.001630 DeepSeek-V3 by $0.008370
Long doc (20K / 1K) $0.035000 $0.006500 DeepSeek-V3 by $0.028500
Very long context (100K / 2K) $0.140000 $0.028650 DeepSeek-V3 by $0.111350

When to choose GPT-5 over DeepSeek-V3

  • Larger context window (400K vs 128K) — relevant when whole documents or long histories must fit in a single call.
  • Supports vision — DeepSeek-V3 does not.
  • Supports reasoning — DeepSeek-V3 does not.

When to choose DeepSeek-V3 over GPT-5

  • Per-token input cost is 78% lower than GPT-5.

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