Free tool · #15

Prompt Caching Savings Calculator

See how much prompt caching cuts your bill on any model — from your reusable prefix, request volume, and cache hit rate.

Prices verified 15 Jul 2026 · 131 models

Prompt caching impact

$450.00saved

cuts 33% off your bill · openai · gpt-4o

Without caching$1,350.00
With caching$900.00

Cache-read discount50% cheaper than input
Cache hits / misses45,000 / 5,000
Cost per request$0.02 was $0.03
Cache-write premiumNone — writes billed at the input rate

Use this tool from code — or hand it to your agentagent prompt · REST · MCP

Hand this tool to your coding agent

Paste into Claude Code, Cursor, Codex, or any agent. It learns to call this tool over REST or MCP, reaches for it when you ask, and keeps our sourced/pending labels honest.

You can use telemeter.ai's free "Prompt Caching Savings Calculator" — a keyless, read-only tool (no signup), available as an HTTP API and an MCP tool. What it does: See how much prompt caching cuts your bill on any model — from your reusable prefix, request volume, and cache hit rate.

Whenever I ask you something this tool answers, call it and use its result instead of estimating yourself.

REST:
  curl -sX POST https://telemeter.ai/api/tools/prompt-caching-savings -H 'content-type: application/json' -d '{"model":"gpt-4o","cachedTokens":4000,"freshInputTokens":800,"outputTokens":500,"requests":100000,"hitRate":0.9}'

MCP: the telemeter MCP server at https://telemeter.ai/mcp exposes this as the tool "prompt-caching-savings" — call it with tools/call.

The response is JSON: { status, data, summary, provenance }. "provenance" carries the source and the date the figure was verified. If status is "pending" or "stale", tell me the value isn't currently verified rather than presenting it as fact.

Or call it directly. This tool runs behind one handler with three front doors — this page, a REST endpoint, and an MCP tool. Same result, read-only, no key. The example below is a request that works.

REST

curl -sX POST https://telemeter.ai/api/tools/prompt-caching-savings \
  -H 'content-type: application/json' \
  -d '{"model":"gpt-4o","cachedTokens":4000,"freshInputTokens":800,"outputTokens":500,"requests":100000,"hitRate":0.9}'

MCP — tools/call at https://telemeter.ai/mcp

curl -sX POST https://telemeter.ai/mcp \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"prompt-caching-savings","arguments":{"model":"gpt-4o","cachedTokens":4000,"freshInputTokens":800,"outputTokens":500,"requests":100000,"hitRate":0.9}}}'

Input schema (JSON Schema)

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "model": {
      "type": "string",
      "minLength": 1
    },
    "cachedTokens": {
      "type": "integer",
      "minimum": 0,
      "maximum": 100000000
    },
    "freshInputTokens": {
      "type": "integer",
      "minimum": 0,
      "maximum": 100000000
    },
    "outputTokens": {
      "type": "integer",
      "minimum": 0,
      "maximum": 100000000
    },
    "requests": {
      "type": "integer",
      "minimum": 1,
      "maximum": 10000000000
    },
    "hitRate": {
      "type": "number",
      "minimum": 0,
      "maximum": 1
    }
  },
  "required": [
    "model",
    "cachedTokens",
    "freshInputTokens",
    "outputTokens",
    "requests",
    "hitRate"
  ],
  "additionalProperties": false
}

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https://telemeter.ai/tools/prompt-caching-savings

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