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Token Counter Model Picker Context Window Cost Calculator Prompt Formatter Temperature JSON Schema System Prompts

8 tools · click to open

Token Counter
Count tokens for GPT-4o, Claude & Gemini. See input costs per model.
Model Picker
5 questions to find the right LLM for your exact use case.
Context Window
Visualize how much of each model's context your text fills.
Cost Calculator
Estimate monthly API costs by request volume across all major models.
Prompt Formatter
Format prompts with XML tags (Claude), Markdown (GPT), or clean output.
Temperature
Explore how temperature 0–2 affects LLM outputs with real examples.
JSON Schema
Build JSON schemas for structured LLM outputs with a visual editor.
System Prompts
12+ ready-to-copy system prompts for coding, writing, analysis & business.
Tool Free

Your text

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Input cost per request + context fill

ModelTokensContextCost

What's your primary use case?

💻 Code generation & debugging
✍️ Creative writing & storytelling
📊 Data analysis & structured output
📄 Long document processing / RAG
💬 Conversational chatbot / assistant

How long are your typical inputs?

Short — under 2,000 tokens (a few pages)
Medium — 2k–50k tokens (docs, reports)
Long — 50k–200k+ tokens (codebases, books)

How important is response speed?

Speed is critical — real-time or streaming
Balanced — speed vs. quality tradeoff is fine
Quality first — speed doesn't matter

What's your budget sensitivity?

Free / open-source only
Low cost — minimize API spend
Best quality, cost is secondary

Do you need tool use / function calling?

Yes — agents, structured output, tool calls
Nice to have
Not needed

Your text

0 tokens · 0 characters

Context window fill by model

Usage parameters

Monthly cost comparison

ModelPer requestMonthlyYearly

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Temperature value

              
0.7

              
Balanced — good default for most uses

              
              

                0.0 deterministic2.0 max randomness
              

              

            

            

              
Example outputs · Task: "Describe the ocean in one sentence."

              

            

          

        


        
        

          

            

              
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Generated JSON schema

              

              

                
                
              

            

          

        


        
        

          

            
            
            
            
            
          

          

        


      

    

  


  
  

    

      
What is LLMKit?

      

        

          
Free token counter

          
Count tokens for GPT-4o, Claude Sonnet, Gemini Pro and 6+ other models instantly. See input costs and context fill — no API key required.

        

        

          
LLM model comparison

          
The model picker asks 5 questions and recommends the right LLM for your use case, balancing cost, context length, speed and capabilities.

        

        

          
Context window calculator

          
Visualize exactly how much of each model's context window your text fills. Instantly see which models can handle your document.

        

        

          
API cost calculator

          
Calculate your monthly LLM API bill based on request volume and token usage. Compare costs across OpenAI, Anthropic, Google and more.

        

        

          
Prompt engineering tools

          
Format prompts for Claude (XML tags) or GPT (Markdown headers). Explore temperature settings with curated examples at each level.

        

        

          
JSON schema & system prompts

          
Build JSON schemas for structured outputs visually, and browse 12+ curated system prompts for coding, writing, analysis and business.