API cost decision in 10 seconds

🔥Claude Opus 5.5 vs NewGLM 5.3 FlashX Legal

Pick GLM 5.3 FlashX Legal when budget and context both matter.

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

Budget verdict

Pick GLM 5.3 FlashX Legal when budget and context both matter.

On the standard 1M input plus 500K output workload, GLM 5.3 FlashX Legal is estimated at $0.99 vs $14 for Claude Opus 5.5, saving $13.01 (92.9% lower).

Cost-first pickGLM 5.3 FlashX Legal
Context-first pickGLM 5.3 FlashX Legal
Sample savings$13.0192.9%
10x traffic gap$130.05

GLM 5.3 FlashX Legal is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $130.05. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

GLM 5.3 FlashX Legal stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickClaude Opus 5.5GLM 5.3 FlashX Legal
Input-heavy / RAG5M input + 500K outputGLM 5.3 FlashX Legal$30$2.48
Balanced workload1M input + 1M outputGLM 5.3 FlashX Legal$24$1.62
Output-heavy chatbot1M input + 5M outputGLM 5.3 FlashX Legal$104$6.62
Cheaper input GLM 5.3 FlashX Legal $4 vs $0.37 / 1M

GLM 5.3 FlashX Legal is $3.63 cheaper per 1M input tokens (90.8% lower; 10.8x difference).

Cheaper output GLM 5.3 FlashX Legal $20 vs $1.25 / 1M

GLM 5.3 FlashX Legal is $18.75 cheaper per 1M output tokens (93.8% lower; 16x difference).

Larger context GLM 5.3 FlashX Legal 1M vs 1.05M

GLM 5.3 FlashX Legal has 48.58K more context (1.05x larger).

Sample workload GLM 5.3 FlashX Legal $14 vs $0.99

GLM 5.3 FlashX Legal is $13.01 cheaper on the standard workload (92.9% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Claude Opus 5.5 Calculating… Estimated API cost
GLM 5.3 FlashX Legal 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

GLM 5.3 FlashX Legal has the lower input price; GLM 5.3 FlashX Legal has the lower output price; GLM 5.3 FlashX Legal offers the larger context window. For the 1M input plus 500K output sample, GLM 5.3 FlashX Legal is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $14 for Claude Opus 5.5 and $0.99 for GLM 5.3 FlashX Legal.

Best Fit

Choose Claude Opus 5.5 when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Choose GLM 5.3 FlashX Legal when you care most about lower input-token price, lower output-token price, and larger context window.

Decision Notes
  • On the standard 1M input plus 500K output workload, GLM 5.3 FlashX Legal is estimated at $0.99 vs $14 for Claude Opus 5.5, saving $13.01 (92.9% lower).
  • GLM 5.3 FlashX Legal is $13.01 cheaper on the standard workload (92.9% lower).
  • GLM 5.3 FlashX Legal is $3.63 cheaper per 1M input tokens (90.8% lower; 10.8x difference).
  • GLM 5.3 FlashX Legal is $18.75 cheaper per 1M output tokens (93.8% lower; 16x difference).
  • GLM 5.3 FlashX Legal has 48.58K more context (1.05x larger).
Head-to-Head Specs
Feature🔥Claude Opus 5.5
(Anthropic)
NewGLM 5.3 FlashX Legal
(Z.ai)
Input Price
prompt tokens per 1M
$4$0.37
Completion Price
per 1M tokens
$20$1.25
Sample Workload Cost
1M input + 500K output
$14$0.99
Context Window1M1.05M
Release Date
Popularity#7

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGLM 5.3 FlashX LegalOn the standard 1M input plus 500K output workload, GLM 5.3 FlashX Legal is estimated at $0.99 vs $14 for Claude Opus 5.5, saving $13.01 (92.9% lower).
High-volume input processingGLM 5.3 FlashX LegalLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGLM 5.3 FlashX LegalLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGLM 5.3 FlashX LegalA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • Claude Haiku 5.5 (batch) can replace Claude Opus 5.5 when lower sample workload cost matters most: $0.17.
  • Claude Haiku 5.5 can replace Claude Opus 5.5 when lower sample workload cost matters most: $0.35.
  • Claude Haiku Latest can replace Claude Opus 5.5 when lower sample workload cost matters most: $0.35.
  • Claude 3 Haiku can replace Claude Opus 5.5 when lower sample workload cost matters most: $0.88.
Larger context near this budget

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

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Anthropic catalog

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

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Z.ai catalog

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

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Claude Opus 5.5

Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...

GLM 5.3 FlashX Legal

GLM-5.3-FlashX-Legal (GLM-Legal) is Z.ai's legal-domain variant of GLM-5.3-FlashX, a native multimodal model that accepts text, image, and video input and produces text. It adds legal-domain mid-training and post-training with reinforcement...