AITOT

Calculator

LLM API Monthly Cost Estimator

Forecast 12-month API spend with scenario saver. Toggle requests/month, token split, and model mix.

Pricing data refreshed:

The AITOT LLM API Monthly Cost Estimator forecasts 12-month spend on OpenAI GPT-5, Claude Sonnet 4.6, Gemini 2.5 Pro, Llama 4, DeepSeek V3, and 17 other models. Inputs: month-1 request volume, growth pattern (flat / linear / exponential), and average tokens per request.

The calculator outputs month-by-month spend, cumulative year-1 total, and the cheapest model at your specific scale. Toggle prompt caching to model 60–90% input savings on Anthropic, 50% on OpenAI, 25% on Google. Save scenarios to compare model choices for executive reporting.

At 100M tokens/month (80M input, 20M output), Claude Sonnet 4.6 costs $540/month, GPT-5 costs $1,400/month, and DeepSeek V3 costs $80/month. The 17× spread is why model choice is the biggest budget lever in 2026 — not caching, not batching, not region.

Year 1 total

Anthropic · Claude Sonnet 4.6

$36,529

Month 1
100,000 req
$1,668$1,668
Month 2
115,000 req
$1,918$3,586
Month 3
130,000 req
$2,168$5,755
Month 4
145,000 req
$2,419$8,173
Month 5
160,000 req
$2,669$10,842
Month 6
175,000 req
$2,919$13,761
Month 7
190,000 req
$3,169$16,930
Month 8
205,000 req
$3,419$20,350
Month 9
220,000 req
$3,670$24,019
Month 10
235,000 req
$3,920$27,939
Month 11
250,000 req
$4,170$32,109
Month 12
265,000 req
$4,420$36,529
MonthlyCumulative

Forecast assumes a single primary model. For multi-model agents, run several scenarios and sum.

What this calculator does

Month-by-month forecast

See spend curve for 12 months, not just an annual total.

Growth patterns

Flat (stable B2B), linear (~10% MoM), or exponential (1.3–2× monthly) — pick yours.

Prompt cache modeling

Toggle cache hit rate to see Anthropic (10% on hit), OpenAI (50%), Google (25%) effective rates.

22 models compared

GPT-5, Claude family, Gemini, Llama 4, DeepSeek, Mistral, Amazon Nova, Cohere.

Scenario saver

Save multiple forecasts to localStorage to compare model + growth combinations.

Year-1 cumulative

Headline number for the budget meeting. Plus inference tax buffer toggle.

Quick comparison

Year-1 cost at 100M tokens/month, flat traffic, 4:1 input:output

ModelMonth-1Year-1 Totalvs Sonnet
Amazon Nova Lite$10$1200.02×
DeepSeek V3$80$9600.15×
Gemini 2.5 Flash$74$8880.14×
Claude Haiku 4.5$144$1,7280.27×
Claude Sonnet 4.6$540$6,4801.00×
OpenAI GPT-5$1,400$16,8002.59×
Claude Opus 4.7$2,700$32,4005.00×

Assumes 80M input + 20M output tokens monthly with no caching.

How to use this calculator

Project 12-month LLM API cost across 22 models with growth modeling.

  1. 1

    Enter month-1 volume

    Set requests per month for the first month. Be realistic — overestimating compounds.

  2. 2

    Pick growth pattern

    Flat (B2B steady), linear (10% MoM), or exponential (1.3× MoM viral growth).

  3. 3

    Set tokens per request

    Average input + output tokens. Chat is ~2k in / 400 out. RAG is ~6k in / 600 out.

  4. 4

    Save and compare scenarios

    Save multiple model choices to compare year-1 cumulative side-by-side.

Why use this calculator

  • ✓22 models tracked monthly
  • ✓Growth pattern modeling (flat/linear/exp)
  • ✓Prompt cache + batch discounts included
  • ✓Save + compare scenarios
  • ✓Inference tax buffer toggle
  • ✓No login required

Frequently Asked Questions

How do I forecast my LLM API spend for 12 months?+
Three inputs: requests per month (month 1), growth pattern (flat/linear/exponential), and average input/output tokens per request. The calculator projects month-by-month spend and gives you the year-1 total. Save scenarios to compare model choices side-by-side.
Which growth pattern should I use — flat, linear, or exponential?+
Flat: stable internal tools or B2B SaaS at scale. Linear: typical growth product adding ~10% MoM. Exponential: pre-PMF startups or viral consumer apps doubling every 1–2 months. Most AI products end up between linear and 1.3× exponential.
Is GPT-5 or Claude Sonnet 4.6 cheaper at 100M tokens per month?+
At 100M tokens (80M input, 20M output): GPT-5 costs $1,400/month, Claude Sonnet 4.6 costs $540/month — a 60% difference. Sonnet 4.6 wins on price at virtually every scale. Switch unless you need GPT-5-specific features.
Does this calculator include prompt caching savings?+
Yes — toggle "cache hit rate" to model it. Anthropic charges 10% of normal input price on cache hits, OpenAI 50%, Google 25%. At 60% cache hit rate on a RAG workload, Anthropic input cost drops 54%. Significant for long-system-prompt apps.
How accurate is a 12-month LLM forecast?+
For the first 3 months: within 10% if your traffic estimate is realistic. For months 6–12: ±30% is normal because pricing changes and you may switch models. Re-run the forecast monthly and pin the saved scenario for executive reporting.
What is the cheapest way to serve 1 billion LLM tokens per month?+
Three paths: (1) DeepSeek V3 at $1.10/M output = ~$220/month for 200M output tokens, (2) Together Llama 4 70B at $0.88/M = $176/month, (3) self-hosted vLLM on 4× H100 at $2.50/hr = $7,200/month flat (worth it above ~3B tokens/month). The calculator compares all three.