API cost decision in 10 seconds

NewGPT Chat Latest vs Step 3.5 Flash

Pick Step 3.5 Flash for lower cost; pick GPT Chat Latest only if the larger context window matters more.

Page updated:  Data confirmed:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Step 3.5 Flash for lower cost; pick GPT Chat Latest only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Step 3.5 Flash is estimated at $0.24 vs $20 for GPT Chat Latest, saving $19.76 (98.8% lower).

Cost-first pickStep 3.5 Flash
Context-first pickGPT Chat Latest
Sample savings$19.7698.8%
10x traffic gap$197.6

GPT Chat Latest has more context, but Step 3.5 Flash saves $19.76 on the standard workload. At 10x that traffic, the same price gap is about $197.6. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Step 3.5 Flash stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickGPT Chat LatestStep 3.5 Flash
Input-heavy / RAG5M input + 500K outputStep 3.5 Flash$40$0.6
Balanced workload1M input + 1M outputStep 3.5 Flash$35$0.39
Output-heavy chatbot1M input + 5M outputStep 3.5 Flash$155$1.59
Cheaper input Step 3.5 Flash $5 vs $0.09 / 1M

Step 3.5 Flash is $4.91 cheaper per 1M input tokens (98.2% lower; 55.6x difference).

Cheaper output Step 3.5 Flash $30 vs $0.3 / 1M

Step 3.5 Flash is $29.7 cheaper per 1M output tokens (99% lower; 100x difference).

Larger context GPT Chat Latest 400K vs 262.14K

GPT Chat Latest has 137.86K more context (1.53x larger).

Sample workload Step 3.5 Flash $20 vs $0.24

Step 3.5 Flash is $19.76 cheaper on the standard workload (98.8% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
GPT Chat Latest Calculating… Estimated API cost
Step 3.5 Flash Calculating… Estimated API cost
Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Step 3.5 Flash has the lower input price; Step 3.5 Flash has the lower output price; GPT Chat Latest offers the larger context window. For the 1M input plus 500K output sample, Step 3.5 Flash is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $20 for GPT Chat Latest and $0.24 for Step 3.5 Flash.

Best Fit

Choose GPT Chat Latest when you care most about larger context window.

Choose Step 3.5 Flash when you care most about lower input-token price, and lower output-token price.

Decision Notes
  • On the standard 1M input plus 500K output workload, Step 3.5 Flash is estimated at $0.24 vs $20 for GPT Chat Latest, saving $19.76 (98.8% lower).
  • Step 3.5 Flash is $19.76 cheaper on the standard workload (98.8% lower).
  • Step 3.5 Flash is $4.91 cheaper per 1M input tokens (98.2% lower; 55.6x difference).
  • Step 3.5 Flash is $29.7 cheaper per 1M output tokens (99% lower; 100x difference).
  • GPT Chat Latest has 137.86K more context (1.53x larger).
Head-to-Head Specs
FeatureNewGPT Chat Latest
(OpenAI)		Step 3.5 Flash
(StepFun)
Input Price
prompt tokens per 1M		$5$0.09
Completion Price
per 1M tokens		$30$0.3
Sample Workload Cost
1M input + 500K output		$20$0.24
Context Window400K262.14K
Release Date

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionStep 3.5 FlashOn the standard 1M input plus 500K output workload, Step 3.5 Flash is estimated at $0.24 vs $20 for GPT Chat Latest, saving $19.76 (98.8% lower).
High-volume input processingStep 3.5 FlashLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsStep 3.5 FlashLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGPT Chat LatestA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • gpt-oss-120b (free) can replace GPT Chat Latest when lower sample workload cost matters most: $0.
  • gpt-oss-20b (free) can replace GPT Chat Latest when lower sample workload cost matters most: $0.
  • gpt-oss-20b can replace GPT Chat Latest when lower sample workload cost matters most: $0.1.
  • gpt-oss-120b can replace GPT Chat Latest when lower sample workload cost matters most: $0.13.
Larger context near this budget
  • Llama 4 Scout offers 10M context with $0.23 sample workload cost.
  • Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
  • Grok 4.20 offers 2M context with $2.5 sample workload cost.
  • GPT-5.5 offers 1.05M context with $20 sample workload cost.

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

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OpenAI catalog

Review all tracked OpenAI models before deciding whether this matchup is the right shortlist.

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StepFun catalog

Check other StepFun models with comparable pricing, context, or release timing.

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Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....