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CalcForge

JSON Token Counter

Estimate LLM token usage for JSON prompts before you hit model limits or cost caps.

503 chars
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Estimated tokens (GPT-4)

Tokens by Model

Character Stats

Characters
No whitespace
Lines
~
Chars/token

Tips to Reduce Token Usage

Remove whitespace for 10-30% savings
Shorten keys
"firstName" → "fn" saves tokens
Remove nulls
Omit null/empty fields when possible
Use arrays
Arrays use fewer tokens than repeated objects

Count tokens in JSON text

Language models bill and truncate by tokens, not characters. Paste JSON destined for a system prompt, tool schema, or RAG context and CalcForge estimates token count so you can trim fields, minify, or split documents before sending.

Good fits

  • Budgeting prompt size for function-calling or JSON-mode completions
  • Comparing pretty vs minified fixtures for token savings
  • Checking whether a schema plus examples fits context limits
  • Debugging truncation when models drop trailing keys
Input JSON (minified): 1,842 characters
Estimated tokens: ~460
Tip: Remove pretty whitespace to save ~12% tokens

Practical notes

  • Estimates approximate provider tokenizers—confirm on your target model for billing.
  • Minify and drop redundant keys before counting for realistic prompt sizes.
  • Pair with JSON Size Analyzer for byte-level transport costs separate from LLM tokens.

Frequently asked questions

Which tokenizer does CalcForge use?

The counter uses a common approximation suitable for planning. Provider APIs may differ slightly—validate critical budgets on the live model.

Does minifying reduce tokens?

Often yes—fewer whitespace tokens. Semantic content unchanged, so duplicate keys still cost the same.

Can I count invalid JSON?

Token counting works on raw text. For structural checks, repair first so you are not paying tokens for broken syntax.

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