ZMIME
Comparison · 3 models · Updated Nov 2, 2026

Seed-OSS-36B-Instruct vs GPT-5 Nano vs Claude Haiku 4.5

GPT-5 Nano comes out ahead, 70 to 66 and 60 on our weighted score, and it is the cheaper option too.

  1. ByteDance Seed

    Seed-OSS-36B-Instruct

    Released Aug 20, 2025

    60/100
    • ECI—
    • Price—
    • Context524K
  2. Our pick

    OpenAI

    GPT-5 Nano

    Released Aug 7, 2025

    70/100
    • ECI139.3
    • Price$0.05 / $0.40
    • Context400K
  3. Anthropic

    Claude Haiku 4.5

    Released Oct 15, 2025

    66/100
    • ECI142.2
    • Price$1.00 / $5.00
    • Context200K
01 — Verdict

GPT-5 Nano is our pick

GPT-5 Nano is the better all-round choice, scoring 70/100 against Claude Haiku 4.5 (66) and Seed-OSS-36B-Instruct (60). It leads on capability. Seed-OSS-36B-Instruct wins on context window. Claude Haiku 4.5 wins on inputs & features. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.

  • CapabilityGPT-5 NanoShared benchmarks: GPT-5 Nano 75.3% · Seed-OSS-36B-Instruct 69.5% · Claude Haiku 4.5 68.9%
  • Lowest priceGPT-5 NanoGPT-5 Nano $0.138 · Claude Haiku 4.5 $2.00 per 1M tokens (3:1 blend) · Seed-OSS-36B-Instruct unpriced
  • Longest contextSeed-OSS-36B-InstructSeed-OSS-36B-Instruct 524,288 · GPT-5 Nano 400,000 · Claude Haiku 4.5 200,000 tokens
  • Widest inputsClaude Haiku 4.5Seed-OSS-36B-Instruct: Text · GPT-5 Nano: Text, Images · Claude Haiku 4.5: Text, Images, PDFs
  • Self-hostingSeed-OSS-36B-InstructPublishes downloadable weights (Apache 2.0)
How the score is built
MeasureWeightSeed-OSS-36B-InstructGPT-5 NanoClaude Haiku 4.5
CapabilityShared benchmarks67%707569
Inputs & features20%357080
Context window13%494432
Overall100%60/10070/10066/100

Left out because at least one model lacks the data: price. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Seed-OSS-36B-Instruct vs GPT-5 Nano vs Claude Haiku 4.5 specifications side by side
SpecificationSeed-OSS-36B-InstructByteDance SeedGPT-5 NanoOpenAIClaude Haiku 4.5Anthropic
Capability
Capabilities Index (ECI)—139.3142.2 (best)
ECI rank—#116 of 165#102 of 165 (best)
GPQA DiamondGraduate-level science questions71.5% (best)69.4%71.2%
FrontierMath Tiers 1–3Research-level mathematics—20.0%—
OTIS Mock AIME 2024–2025Competition mathematics67.5%81.1% (best)66.7%
SimpleQA VerifiedShort factual questions—11.7%13.2% (best)
Price per million tokens
Input—$0.05 (best)$1.00
Output—$0.40 (best)$5.00
Cached input—$0.005 (best)$0.10
Blended (3:1)—$0.138 (best)$2.00
Long-context rate—Same rateSame rate
Price source—Official OpenAI APIOfficial Anthropic API
Limits
Context window524,288 tokens (best)400,000 tokens200,000 tokens
Max output524,288 tokens (best)128,000 tokens64,000 tokens
Inputs and features
TextYesYesYes
ImagesNoYesYes
PDFsNoNoYes
AudioNoNoNo
VideoNoNoNo
ReasoningYesYesminimal · low · medium · highYes
Tool callingYesYesYes
Structured outputNoYesYes
Availability
WeightsOpenApache 2.0ProprietaryProprietary
API model ID—gpt-5-nanoclaude-haiku-4-5
API providers—3048 (best)
ReleasedAug 20, 2025Aug 7, 2025Oct 15, 2025
Knowledge cutoffJul 2024May 30, 2024Feb 28, 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Seed-OSS-36B-Instruct—
  • GPT-5 Nano$1.30
  • Claude Haiku 4.5$20.00
04 — Questions

Which should you choose?

Which is better: Seed-OSS-36B-Instruct, GPT-5 Nano or Claude Haiku 4.5?

GPT-5 Nano is the better all-round choice, scoring 70/100 against Claude Haiku 4.5 (66) and Seed-OSS-36B-Instruct (60). It leads on capability. Seed-OSS-36B-Instruct wins on context window. Claude Haiku 4.5 wins on inputs & features. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.

Which is cheaper, Seed-OSS-36B-Instruct, GPT-5 Nano or Claude Haiku 4.5?

GPT-5 Nano is cheaper at $0.05 input / $0.40 output per million tokens (official OpenAI API price). Claude Haiku 4.5 costs $1.00 input / $5.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.138 per million tokens for GPT-5 Nano versus $2.00 for Claude Haiku 4.5 (15× as much). Seed-OSS-36B-Instruct has no published per-token price.

Which scores higher on benchmarks?

Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025): GPT-5 Nano 75.3%, Seed-OSS-36B-Instruct 69.5% and Claude Haiku 4.5 68.9%. On individual benchmarks: GPQA Diamond — Seed-OSS-36B-Instruct 71.5%, Claude Haiku 4.5 71.2%, GPT-5 Nano 69.4%; OTIS Mock AIME 2024–2025 — GPT-5 Nano 81.1%, Seed-OSS-36B-Instruct 67.5%, Claude Haiku 4.5 66.7%.

Which is better for coding?

There are no published SWE-bench Verified results for Seed-OSS-36B-Instruct, GPT-5 Nano and Claude Haiku 4.5 yet, so there is no like-for-like coding score. On overall capability, GPT-5 Nano leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

Seed-OSS-36B-Instruct has the largest context window at 524,288 tokens, against 400,000 for GPT-5 Nano and 200,000 for Claude Haiku 4.5. Maximum output per response: Seed-OSS-36B-Instruct up to 524,288, GPT-5 Nano up to 128,000, Claude Haiku 4.5 up to 64,000 tokens.

Which can read images, PDFs, audio or video?

Seed-OSS-36B-Instruct accepts text; GPT-5 Nano accepts text and images; Claude Haiku 4.5 accepts text, images and PDFs. Claude Haiku 4.5 handles the widest range of inputs.

Are any of these open source?

Seed-OSS-36B-Instruct publishes its weights (Apache 2.0) and can be self-hosted; GPT-5 Nano and Claude Haiku 4.5 is proprietary.

Which is newer?

Claude Haiku 4.5 is the newest, released Oct 15, 2025. Seed-OSS-36B-Instruct came out Aug 20, 2025; GPT-5 Nano came out Aug 7, 2025. Knowledge cutoff: Seed-OSS-36B-Instruct Jul 2024, GPT-5 Nano May 30, 2024, Claude Haiku 4.5 Feb 28, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.