API cost decision in 10 seconds

NewUnion Alpha vs NewGPT-6 Astra

Pick Union Alpha for lower cost; pick GPT-6 Astra only if the larger context window matters more.

Page updated: 2026-09-16T15:08:45Z Data confirmed: 2026-09-16T16:08:25Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Union Alpha for lower cost; pick GPT-6 Astra only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $35 for GPT-6 Astra, saving $35 (100% lower).

Cost-first pickUnion Alpha

Context-first pickGPT-6 Astra

Sample savings$35100%

10x traffic gap$350

GPT-6 Astra has more context, but Union Alpha saves $35 on the standard workload. At 10x that traffic, the same price gap is about $350. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Union Alpha stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Union Alpha	GPT-6 Astra
Input-heavy / RAG	5M input + 500K output	Union Alpha	$0	$75
Balanced workload	1M input + 1M output	Union Alpha	$0	$60
Output-heavy chatbot	1M input + 5M output	Union Alpha	$0	$260

Cheaper input Union Alpha $0 vs $10 / 1M

Union Alpha is free for input tokens while GPT-6 Astra costs $10 per 1M tokens.

Cheaper output Union Alpha $0 vs $50 / 1M

Union Alpha is free for output tokens while GPT-6 Astra costs $50 per 1M tokens.

Larger context GPT-6 Astra 262.14K vs 1.05M

GPT-6 Astra has 787.86K more context (4.01x larger).

Sample workload Union Alpha $0 vs $35

Union Alpha is free for the standard workload while the other model is estimated at $35.

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Union Alpha Calculating… Estimated API cost

GPT-6 Astra 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

Union Alpha has the lower input price; Union Alpha has the lower output price; GPT-6 Astra offers the larger context window. For the 1M input plus 500K output sample, Union Alpha is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0 for Union Alpha and $35 for GPT-6 Astra.

Best Fit

Choose Union Alpha when you care most about lower input-token price, and lower output-token price.

Choose GPT-6 Astra when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $35 for GPT-6 Astra, saving $35 (100% lower).
Union Alpha is free for the standard workload while the other model is estimated at $35.
Union Alpha is free for input tokens while GPT-6 Astra costs $10 per 1M tokens.
Union Alpha is free for output tokens while GPT-6 Astra costs $50 per 1M tokens.
GPT-6 Astra has 787.86K more context (4.01x larger).

Head-to-Head Specs

Feature	NewUnion Alpha (stealth)	NewGPT-6 Astra (OpenAI)
Input Price prompt tokens per 1M	$0	$10
Completion Price per 1M tokens	$0	$50
Sample Workload Cost 1M input + 500K output	$0	$35
Context Window	262.14K	1.05M
Release Date	2026-09-16	2026-09-04

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Union Alpha	On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $35 for GPT-6 Astra, saving $35 (100% lower).
High-volume input processing	Union Alpha	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Union Alpha	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	GPT-6 Astra	A 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-6 Astra when lower sample workload cost matters most: $0.
gpt-oss-20b (free) can replace GPT-6 Astra when lower sample workload cost matters most: $0.
gpt-oss-20b can replace GPT-6 Astra when lower sample workload cost matters most: $0.1.
gpt-oss-120b can replace GPT-6 Astra when lower sample workload cost matters most: $0.12.

Larger context near this budget

Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
DeepSeek V4 Flash 0731 offers 1.31M context with $0.12 sample workload cost.
GLM 5.3 Flash offers 1.31M context with $0.24 sample workload cost.

Popular competitors

Qwen3.8 Max (0902) · Qwen · #1
GPT-5.6 Luna · OpenAI · #2
Hy4 preview · Tencent · #3
DeepSeek V4 Flash 0731 · DeepSeek · #4

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

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stealth catalog

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

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OpenAI catalog

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

Open OpenAI models

Union Alpha

Union Alpha is a multimodal model built for research, coding, and agentic workflows, while delivering frontier-level performance across a broad range of general-purpose tasks. Union Alpha is a stealth model....

GPT-6 Astra

GPT-6 Astra is OpenAI's flagship model for demanding end-to-end work. It is suited for advanced analysis, software engineering, deep research, scientific work, and document creation, with particular strengths in long-horizon...