GPT-5 Nano vs DeepSeek-V3: Detailed Comparison

Choosing between GPT-5 Nano (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 Nano costs $0.05/M input vs $0.27/M for DeepSeek-V3; context windows are 400K vs 128K tokens. Detailed breakdown below.

Side-by-side specs

SpecGPT-5 NanoDeepSeek-V3
ProviderOpenAIDeepSeek
Released2025-08-072024-12-26
Input price $0.05/M $0.27/M
Output price $0.40/M $1.10/M
Cached input $0.0050/M $0.0700/M
Context window 400K 128K
Max output 64K 8K
Modalities text text
Tokenizer o200k_base deepseek

Capability matrix

CapabilityGPT-5 NanoDeepSeek-V3
function calling Yes Yes
json mode Yes Yes
streaming Yes Yes

Benchmark comparison

Higher is better for all benchmarks shown.

BenchmarkCategoryGPT-5 NanoDeepSeek-V3Δ
MMLU-Pro general 75.9
HumanEval coding 82.6

Per-call cost on typical workloads

Workload (in/out tokens)GPT-5 NanoDeepSeek-V3Cheaper by
Standard chat (1K / 500) $0.000250 $0.000820 GPT-5 Nano by $0.000570
RAG (4K / 500) $0.000400 $0.001630 GPT-5 Nano by $0.001230
Long doc (20K / 1K) $0.001400 $0.006500 GPT-5 Nano by $0.005100
Very long context (100K / 2K) $0.005600 $0.028650 GPT-5 Nano by $0.023050

When to choose GPT-5 Nano over DeepSeek-V3

  • Per-token input cost is 81% lower — meaningful for high-volume workloads.
  • Larger context window (400K vs 128K) — relevant when whole documents or long histories must fit in a single call.

When to choose DeepSeek-V3 over GPT-5 Nano

  • DeepSeek-V3 fits when your stack is already on DeepSeek.

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