AI & Computing

LLM API Cost Calculator (Tokens per Request to Monthly Cost)

Enter tokens per request and traffic to estimate your monthly AI API bill.

By TheCalcTools Updated Formula checked and tested

Your numbers

Symbol only: enter amounts in the currency you pick.
$
$
%
Cached input is typically billed at about 10% of the normal input price

Your results

Monthly cost
Monthly cost
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Cost per request
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Cost per day
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Cost per 1,000 requests
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Tokens per month (millions)
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Share of cost from output
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LLM API Cost Calculator (Tokens per Request to Monthly Cost) by TheCalcTools

How the LLM API Cost Calculator (Tokens per Request to Monthly Cost) works

API prices are quoted per million tokens, separately for input (your prompt, documents and conversation history) and output (the model’s reply). Output tokens usually cost several times more than input tokens.

Prompt caching bills repeated input (a long system prompt or document reused across requests) at a fraction of the normal price; this calculator assumes cached input costs 10% of the input price. Batch APIs process requests asynchronously at a 50% discount.

Preset prices are Anthropic’s published Claude API rates as of October 2026. Choose “Custom rates” to enter any provider’s prices, and always check the provider’s current price list.

The formula

Cost per request = (input tokens × input price + output tokens × output price) ÷ 1,000,000Monthly cost = cost per request × requests per day × days

Worked example

Using the default values shown in the calculator:

Model and priceClaude Sonnet 5.5 ($2 / $10)
Input price per 1M tokens$2
Output price per 1M tokens$10
Input tokens per request3000
Output tokens per request600
Requests per day2000
Share of input served from cache0 %
Batch processing (50% off)No
Days per month30
  1. Sonnet 5.5: 3,000 input tokens × $2 + 600 output tokens × $10 per million = $0.01 per request.
  2. At 2,000 requests a day for 30 days: $720.00 a month.

Result:

Monthly cost$720.00
Cost per request$0.01
Cost per day$24.00
Cost per 1,000 requests$12.00
Tokens per month (millions)216.00
Share of cost from output50.0%

Frequently asked questions

How many tokens is a page of text?

In English one token is about three quarters of a word, so a 500-word page is about 650 to 700 tokens. Use the words to tokens calculator for estimates.

Why is my bill higher than expected?

Chat applications resend the whole conversation as input on every turn, so input tokens grow with conversation length. Long system prompts, tool definitions and retrieved documents also count as input.

Do reasoning or thinking tokens count?

Yes. Models that think before answering bill thinking tokens as output tokens, so set output tokens per request to include them.

Sources and further reading

Words to Tokens Calculator (LLM Token Estimate)Convert words or characters to an estimated token count, and see what fits in a context… GPU Memory (VRAM) Calculator for LLMsEnter the model size, precision and context to estimate how much VRAM you need LLM Tokens per Second Calculator (Memory Bandwidth)Enter memory bandwidth and model size to estimate generation speed RAG Chunking Calculator (Chunks, Overlap and Embedding Cost)Enter your corpus size and chunk settings to plan a RAG index AI Energy and CO₂ Calculator (GPU Training or Inference)Enter GPU power and hours to estimate energy, cost and CO₂ GPU Cloud Cost CalculatorEnter GPU prices and usage to compare renting with buying

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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.