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DeepSeek V3.1 Terminus vs GPT-5 Nano

DeepSeek V3.1 Terminus leads GPT-5 Nano on the Artificial Analysis Intelligence Index, 14.8 to 13.0, and GPT-5 Nano costs 2.5x less per output token ($0.40 vs $1.0142 per million). Updated October 22, 2026; 40 benchmarks have a result for both.

Replace DeepSeek V3.1 Terminus Replace GPT-5 Nano
DeepSeek V3.1 TerminusDeepSeek
Coding
No data
Overall
No data
Output $/M
$1.0142
38
GPT-5 NanoOpenAI
Coding
No data
Overall
35.6
Output $/M
$0.40
2
vs boards won of 40 shared

DeepSeek V3.1 Terminus or GPT-5 Nano: which to pick

Neither model has a coding score yet, so the two cannot be ranked on coding.

Pick DeepSeek V3.1 Terminus for work measured by Kagi LLM Benchmark or IFBench, where it leads.

Model ADeepSeek V3.1 TerminusDeepSeekNot benchmarkedNo coding benchmarkNo cost per solved taskModel BGPT-5 NanoOpenAINot benchmarkedNo coding benchmark$0.109 per solved task
Shared results
40
DeepSeek V3.1 Terminus only
5
GPT-5 Nano only
47
Like-for-like categories
8 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
DeepSeek V3.1 Terminus not benchmarked, GPT-5 Nano not benchmarked.
Widest category
Knowledge, 19.1 points apart on average over 5 shared benchmarks.
Widest single gap
LMArena Text: legal and government: DeepSeek V3.1 Terminus 1457 against GPT-5 Nano 1298, 26.6 points apart on a 0 to 100 scale.
Output price
DeepSeek V3.1 Terminus $1.0142 against GPT-5 Nano $0.40 per million output tokens, 2.5x apart.
Context window
DeepSeek V3.1 Terminus takes 164K tokens, GPT-5 Nano 400K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryDeepSeek V3.1 TerminusBarsGPT-5 NanoTies
Coding40
Intelligence10
Agentic work10
Reasoning41
Math30
Knowledge50
Web design60
General141
All shared boards382
CodingLike-for-likeSix of these boards feed the Vibe Coding Index40
Coding benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
SWE-bench VerifiedNot measured34.8%Only GPT-5 Nano measured
AA Coding Index43.5Not measuredOnly DeepSeek V3.1 Terminus measured
LiveCodeBench (Vals AI)Not measured70.2%Only GPT-5 Nano measured
LiveCodeBench (Artificial Analysis run)79.8%78.9%DeepSeek V3.1 Terminus
SciCode38.0%Not measuredOnly DeepSeek V3.1 Terminus measured
Terminal-Bench Hard (Artificial Analysis run)31.8%17.4%DeepSeek V3.1 Terminus
Terminal-BenchNot measured21.8%Only GPT-5 Nano measured
WeirdMLNot measured38.1%Only GPT-5 Nano measured
ALE-Bench745.2Not measuredOnly DeepSeek V3.1 Terminus measured
LMArena Text: coding14251351DeepSeek V3.1 Terminus
LMArena Text: software and IT14261345DeepSeek V3.1 Terminus
Neither model has a result on the other 28 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
AA Intelligence Index14.813.0DeepSeek V3.1 Terminus
Epoch Capabilities IndexNot measured139.2Only GPT-5 Nano measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
AA Agentic Index6.8Not measuredOnly DeepSeek V3.1 Terminus measured
τ²-Bench Telecom37.1%36.5%DeepSeek V3.1 Terminus
Berkeley Function Calling Leaderboard (BFCL)Not measured51.4%Only GPT-5 Nano measured
Neither model has a result on the other 38 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index41
Reasoning benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
GPQA DiamondNot measured63.4%Only GPT-5 Nano measured
MMMU Pro (Vals AI)Not measured70.9%Only GPT-5 Nano measured
GPQA Diamond (Artificial Analysis run)79.2%67.6%DeepSeek V3.1 Terminus
Humanity's Last Exam (Artificial Analysis run)16.4%9.5%DeepSeek V3.1 Terminus
GPQA Diamond (Epoch AI run)Not measured69.4%Only GPT-5 Nano measured
ARC-AGINot measured20.7%Only GPT-5 Nano measured
ARC-AGI-2Not measured2.6%Only GPT-5 Nano measured
Chess puzzlesNot measured22.0%Only GPT-5 Nano measured
Mystery game puzzlesNot measured9.0%Only GPT-5 Nano measured
VPCTNot measured37.2%Only GPT-5 Nano measured
LMArena Text: hard prompts14261328DeepSeek V3.1 Terminus
LMArena Text: expertNot measured1321Only GPT-5 Nano measured
LMArena Text: hard prompts in English14321338DeepSeek V3.1 Terminus
LMArena Vision: diagramsNot measured1141Only GPT-5 Nano measured
LMArena Vision: homeworkNot measured1157Only GPT-5 Nano measured
Kagi LLM Benchmark57.4%62.2%GPT-5 Nano
Neither model has a result on the other 6 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index30
Math benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
AIMENot measured81.2%Only GPT-5 Nano measured
MATH 500 (Vals AI)Not measured93.8%Only GPT-5 Nano measured
MGSM (Vals AI)Not measured89.3%Only GPT-5 Nano measured
AA Math Index89.783.7DeepSeek V3.1 Terminus
AIME 2025 (Artificial Analysis run)89.7%83.7%DeepSeek V3.1 Terminus
OTIS Mock AIMENot measured81.1%Only GPT-5 Nano measured
FrontierMath, tiers 1 to 3Not measured20.0%Only GPT-5 Nano measured
FrontierMath, tier 4Not measured2.4%Only GPT-5 Nano measured
ProofBenchNot measured12.0%Only GPT-5 Nano measured
MATH level 5Not measured95.2%Only GPT-5 Nano measured
LMArena Text: math14021317DeepSeek V3.1 Terminus
LMArena Text: mathematical workNot measured1326Only GPT-5 Nano measured
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index50
Knowledge benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
MMLU ProNot measured76.1%Only GPT-5 Nano measured
LegalBench (Vals AI)Not measured50.1%Only GPT-5 Nano measured
CaseLaw (Vals AI)Not measured52.6%Only GPT-5 Nano measured
TaxEval (Vals AI)Not measured67.4%Only GPT-5 Nano measured
MortgageTax (Vals AI)Not measured53.6%Only GPT-5 Nano measured
MedQA (Vals AI)Not measured93.3%Only GPT-5 Nano measured
MedCode (Vals AI)Not measured30.4%Only GPT-5 Nano measured
MMLU Pro (Artificial Analysis run)85.1%78.0%DeepSeek V3.1 Terminus
SimpleQA VerifiedNot measured11.7%Only GPT-5 Nano measured
LMArena Text: science14511318DeepSeek V3.1 Terminus
LMArena Text: medicine and healthcare14681335DeepSeek V3.1 Terminus
LMArena Text: legal and government14571298DeepSeek V3.1 Terminus
LMArena Text: business and finance14141311DeepSeek V3.1 Terminus
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
Design Arena: websites11871101DeepSeek V3.1 Terminus
Design Arena: UI components11821064DeepSeek V3.1 Terminus
Design Arena: game dev11311044DeepSeek V3.1 Terminus
Design Arena: data viz11681056DeepSeek V3.1 Terminus
Design Arena: 3D1141965DeepSeek V3.1 Terminus
Design Arena: all code categories11751084DeepSeek V3.1 Terminus
Design Arena: SVG1065Not measuredOnly DeepSeek V3.1 Terminus measured
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index141
General benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
SAGE (Vals AI)Not measured30.4%Only GPT-5 Nano measured
MedScribe (Vals AI)Not measured72.9%Only GPT-5 Nano measured
IFBench57.0%67.6%GPT-5 Nano
Long context reasoning (AA-LCR)69.3%45.0%DeepSeek V3.1 Terminus
DTBench81.3%62.7%DeepSeek V3.1 Terminus
LMCA28.6%7.9%DeepSeek V3.1 Terminus
Fiction.LiveBenchNot measured44.4%Only GPT-5 Nano measured
LMArena Text14191320DeepSeek V3.1 Terminus
LMArena Text: instruction following14041306DeepSeek V3.1 Terminus
LMArena Text: creative writing14031249DeepSeek V3.1 Terminus
LMArena VisionNot measured1159Only GPT-5 Nano measured
LMArena Text: English14291321DeepSeek V3.1 Terminus
LMArena Text: non-English14081313DeepSeek V3.1 Terminus
LMArena Text: ChineseNot measured1356Only GPT-5 Nano measured
LMArena Text: GermanNot measured1327Only GPT-5 Nano measured
LMArena Text: JapaneseNot measured1227Only GPT-5 Nano measured
LMArena Text: KoreanNot measured1269Only GPT-5 Nano measured
LMArena Text: SpanishNot measured1360Only GPT-5 Nano measured
LMArena Text: Russian14351296DeepSeek V3.1 Terminus
LMArena Text: Polish14271314DeepSeek V3.1 Terminus
LMArena Text: multi-turn14111311DeepSeek V3.1 Terminus
LMArena Text: longer queries14221312DeepSeek V3.1 Terminus
LMArena Text: writing and language14091283DeepSeek V3.1 Terminus
LMArena Text: entertainment and media13911268DeepSeek V3.1 Terminus
LMArena Vision: EnglishNot measured1170Only GPT-5 Nano measured
LMArena Vision: ChineseNot measured1176Only GPT-5 Nano measured
LMArena Vision: reading textNot measured1152Only GPT-5 Nano measured
LMArena Vision: humorNot measured1110Only GPT-5 Nano measured
Neither model has a result on the other 18 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for DeepSeek V3.1 Terminus and GPT-5 Nano
BenchmarkDeepSeek V3.1 TerminusGPT-5 NanoLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

DeepSeek V3.1 Terminus$0.0008Fits in one request
GPT-5 Nano$0.0003Fits in one request

GPT-5 Nano costs less

Repository review

50K input + 3K output tokens

DeepSeek V3.1 Terminus$0.018Fits in one request
GPT-5 Nano$0.0037Fits in one request

GPT-5 Nano costs less

Agent loop

200K input + 10K output tokens

DeepSeek V3.1 Terminus$0.071Exceeds the context window
GPT-5 Nano$0.014Fits in one request

GPT-5 Nano costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of DeepSeek V3.1 Terminus and GPT-5 Nano
SpecificationDeepSeek V3.1 TerminusOpenAI GPT-5 Nano
MakerDeepSeekOpenAI
WeightsOpen weightsNo public weights listed
ReleasedSeptember 22, 2025August 7, 2025
Context window164K400K
Input $/Mtok$0.3063$0.05
Output $/Mtok$1.0142$0.40
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it00
Cost per solved taskNot computable$0.109
SourceOpenRouter listingOpenRouter listing

Questions

Is DeepSeek V3.1 Terminus better than GPT-5 Nano for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick DeepSeek V3.1 Terminus for work measured by Kagi LLM Benchmark or IFBench, where it leads.

Which is cheaper, DeepSeek V3.1 Terminus or GPT-5 Nano?

DeepSeek V3.1 Terminus costs $0.3063 per million input tokens and $1.0142 per million output tokens; GPT-5 Nano costs $0.05 and $0.40. Cost per solved task is known for GPT-5 Nano only.

Which has the bigger context window, DeepSeek V3.1 Terminus or GPT-5 Nano?

GPT-5 Nano, with 400K tokens against 164K.

How many benchmarks is the DeepSeek V3.1 Terminus vs GPT-5 Nano comparison based on?

40 benchmarks have a result for both models as of October 22, 2026. DeepSeek V3.1 Terminus's coding index rests on 0 independent benchmarks and GPT-5 Nano's on 0. Where only one model has a result, the page says so instead of naming a winner.

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