Baidu: ERNIE 4.5 21B A3B Thinking

Public pricingIntelligence 79/100Medium memoryDeep thinkingTool use

Baidu: ERNIE 4.5 21B A3B Thinking is a text model for coding, debugging, and technical work. It combines strong coding performance and deep reasoning and planning with a 131K tokens context window and a low-cost profile. Use it for coding, debugging, and technical writing when accuracy, context, and control matters.

Input

$0.07/1M

Output

$0.28/1M

Cached

$0.01/1M

Batch

$0.04/1M

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What would ERNIE 4.5 21B A3B Thinking cost you?

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Technical specifications

ERNIE 4.5 21B A3B Thinking at a glance.

Memory

131,072

tokens

Max reply

65,536

tokens

Memory tier

Medium

a long report or a codebase file

Tokenizer

—

Released

Sep 2025

Training cutoff

Feb 2025

Availability

Public pricing

Status

active

What it can do

Capabilities & limits.

  • Understands images
  • Deep step-by-step thinking
  • Uses tools / calls functions
  • Strict JSON output
  • Streams replies
  • Fine-tunable on your data

When to pick ERNIE 4.5 21B A3B Thinking

  • Multi-step reasoning, research agents, or hard math.
  • Agentic workflows that call tools or APIs.
  • High-volume workloads where unit cost matters.

When to look elsewhere

  • Your workload involves images — pick a vision-capable model instead.

Alternatives

Similar models to compare.

FAQ

ERNIE 4.5 21B A3B Thinking — the questions we see most.

Pricing, capabilities, alternatives — generated from the same data that powers the calculator above.

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At a typical workload of 50,000 conversations a month with 1,500-token prompts and 800-token replies, ERNIE 4.5 21B A3B Thinking costs roughly $16 per month. Input is $0.07 /1M tokens and output is $0.28 /1M tokens.
ERNIE 4.5 21B A3B Thinking has a 131,072-token context window (medium memory — a long report or a codebase file). That means you can fit about 24,576 words of input and history in a single call.
Beyond text generation, ERNIE 4.5 21B A3B Thinking supports deep step-by-step reasoning, calling functions / tools, strict JSON output, fine-tuning on your own data. It streams replies by default.
ERNIE 4.5 21B A3B Thinking was released in September 2025, with training data cut off around February 2025.
Models in a similar class include Seed 1.6 Flash, Gemini 2.0 Flash Lite, gpt-oss-safeguard-20b. The "Similar models" section below this FAQ links into each.

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