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AI Choice Engine

Model comparison

DeepSeek V4 Pro vs GPT-5.5

DeepSeek against OpenAI, compared on context, price, and attributed benchmark results.

Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

DeepSeek

DeepSeek V4 Pro

Frontier · Open weights

vs

OpenAI

GPT-5.5

Frontier

AI model capability comparison
SpecificationDeepSeek V4 ProGPT-5.5
ProviderDeepSeekOpenAI
TierFrontierFrontier
Context window1MWinner: 1.05M
Max outputWinner: 384K128K
Input / 1M tokensWinner: $1.32$5
Output / 1M tokensWinner: $3.96$30
WeightsOpenClosed
Parameters1.6T total / 49B active (MoE)Not verifiedUnverified
Reasoning levelslow, high, maxnone, low, medium, high, xhigh
Modalitiestexttext, image
LicenseMITNot verifiedUnverified
API model iddeepseek-v4-progpt-5.5
ReleasedApril 24, 2026April 23, 2026
Artificial Analysis Intelligence Index [max] · source date DeepSeek V4 Pro: 2026-10-0136Not verifiedUnverified
SWE-bench Verified [max] · source date DeepSeek V4 Pro: 2026-04-2480.6Not verifiedUnverified
GPQA Diamond [max] · source date DeepSeek V4 Pro: 2026-04-2490.1Not verifiedUnverified
GPQA Diamond · source date GPT-5.5: 2026-07-27Not verifiedUnverified93.5
Humanity's Last Exam [max] · source date DeepSeek V4 Pro: 2026-04-2448.2Not verifiedUnverified
Humanity's Last Exam · source date DeepSeek V4 Pro: 2026-08-1342.7Not verifiedUnverified
Humanity's Last Exam · source date DeepSeek V4 Pro: 2026-08-1360Not verifiedUnverified
Humanity's Last Exam · source date GPT-5.5: 2026-04-23Not verifiedUnverified52.2
MMLU-Pro [max] · source date DeepSeek V4 Pro: 2026-04-2487.5Not verifiedUnverified
Terminal-Bench 2.1 · source date DeepSeek V4 Pro: 2026-08-1387.9Not verifiedUnverified
Terminal-Bench 2.1 · source date GPT-5.5: 2026-07-27Not verifiedUnverified83.4
DeepSWE 1.1 · source date DeepSeek V4 Pro: 2026-08-1362.7Not verifiedUnverified

Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Pricing tiers

DeepSeek V4 Pro: Official peak rates $1.32/$3.96 per MTok; off-peak $0.66/$1.98 (cache-miss). Cache hit $0.044 peak / $0.022 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC, excluding Chinese public holidays; weekends, holidays and all other hours are off-peak. Open weights (MIT). 1.6T/49B active MoE.

GPT-5.5: Standard $5/$30 per MTok; prompts above 272K bill 2x input and 1.5x output for the full session in Standard/Batch/Flex. Cached input $0.50; short-context Batch $2.50/$15. Regional/FedRAMP processing adds 10% where eligible.

FrontierOpen weightsRecord checked October 1, 2026

DeepSeek V4 Pro

DeepSeek V4 Pro is DeepSeek's large open-weight (MIT) MoE with a 1M-token context — DeepSeek says the cheaper V4.1-Flash now beats it.

Best for

  • Cost-sensitive hosted agents
  • Open-weight deployments
  • High-volume coding

Watch out

The current tariff identifies DeepSeek-V4-Pro-0813. DeepSeek's current changelog reverses the earlier September 14 re-route plan and says it will continue serving V4 Pro at unchanged rates until further notice. Original April benchmark/checkpoint results are not the current 0813 evaluation. Self-hosting memory depends on quantization, offloading and hardware.

FrontierRecord checked October 1, 2026

GPT-5.5

OpenAI’s April 2026 model for reasoning, coding and professional work, with a 1.05M-token context. Retained benchmark scores identify their source and configuration.

Best for

  • Reasoning
  • Agentic coding
  • Long-context work

Watch out

An older model, still listed in the API. GPT-5.5 retires from ChatGPT, Work and Codex on October 14, 2026; that notice does not affect the OpenAI API.

When the cheaper one wins

DeepSeek V4 Pro is cheaper on output at $3.96 per million tokens against $30 for GPT-5.5 — about 7.6×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. On DeepSWE 1.1, DeepSeek V4 Pro is 62.8% Pass@1 at $0.24/task versus GPT-5.5 at 67% / $7.23/task. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.

Run the model picker

Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 4/5 core specs verified on both sides — Not published for at least one side: parameter count.
  • No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
  • Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? DeepSeek V4 Pro · GPT-5.5

Common questions

DeepSeek V4 Pro vs GPT-5.5

Answered from the verified figures on this page rather than general guidance.

Is DeepSeek V4 Pro or GPT-5.5 cheaper for input?
DeepSeek V4 Pro is cheaper at $1.32 per million input tokens, against $5 for GPT-5.5 — roughly 3.8× the price. Estimate both input and output token volume for your workload. These are base rates; DeepSeek V4 Pro: Official peak rates $1.32/$3.96 per MTok; off-peak $0.66/$1.98 (cache-miss). Cache hit $0.044 peak / $0.022 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC, excluding Chinese public holidays; weekends, holidays and all other hours are off-peak. Open weights (MIT). 1.6T/49B active MoE. GPT-5.5: Standard $5/$30 per MTok; prompts above 272K bill 2x input and 1.5x output for the full session in Standard/Batch/Flex. Cached input $0.50; short-context Batch $2.50/$15. Regional/FedRAMP processing adds 10% where eligible.
Is DeepSeek V4 Pro or GPT-5.5 cheaper for output?
DeepSeek V4 Pro is cheaper at $3.96 per million output tokens, against $30 for GPT-5.5 — roughly 7.6× the price. Estimate both input and output token volume for your workload. These are base rates; DeepSeek V4 Pro: Official peak rates $1.32/$3.96 per MTok; off-peak $0.66/$1.98 (cache-miss). Cache hit $0.044 peak / $0.022 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC, excluding Chinese public holidays; weekends, holidays and all other hours are off-peak. Open weights (MIT). 1.6T/49B active MoE. GPT-5.5: Standard $5/$30 per MTok; prompts above 272K bill 2x input and 1.5x output for the full session in Standard/Batch/Flex. Cached input $0.50; short-context Batch $2.50/$15. Regional/FedRAMP processing adds 10% where eligible.
Which has the larger context window, DeepSeek V4 Pro or GPT-5.5?
GPT-5.5 accepts 1.05M tokens against 1M for DeepSeek V4 Pro. This only matters if you routinely send very long documents or large codebases.
Do DeepSeek V4 Pro and GPT-5.5 support the same reasoning levels?
DeepSeek V4 Pro exposes low, high, max, while GPT-5.5 exposes none, low, medium, high, xhigh.
Should I use DeepSeek V4 Pro or GPT-5.5?
Both are classified in our frontier tier; this editorial grouping does not imply equal capability. DeepSeek V4 Pro is a candidate for cost-sensitive hosted agents; GPT-5.5 is a candidate for reasoning. Compare accuracy, tool reliability, latency and cost on representative tasks.
Can I self-host DeepSeek V4 Pro or GPT-5.5?
DeepSeek V4 Pro publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. GPT-5.5 is a closed model whose supported access paths are controlled by its provider.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: DeepSeek V4 Pro costs $1.32 per 1M tokens versus $5 for GPT-5.5 — a 3.8x difference at the headline tier.
  • Context: GPT-5.5 takes 1.05M against 1M for DeepSeek V4 Pro — only decisive if your prompts approach the smaller window.
  • Deployment: DeepSeek V4 Pro publishes weights you can self-host; the other is API-only.
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