A practical LLM cost simulator for builders.

llmcalc.app exists because LLM pricing has gotten genuinely complicated. The headline "$X per million tokens" rarely matches what you actually pay. Cache reads, cache writes, batch discounts, long-context tiers, reasoning tokens, retries, multi-turn loops — these compound, and most calculators ignore them.

What this is

• A multi-model token counter that runs entirely in your browser.
• A cost calculator with input/output/cache/batch/long-context fields modeled correctly.
• Three differentiated calculators: prompt-caching ROI, batch decision tool, and a multi-turn agent-loop simulator with workload templates.
• Model and comparison reference pages, all driven from a single models.json.

What it isn't

• A replacement for your provider's invoice. Always reconcile against the real bill.
• A live monitor. Pricing data is verified periodically, not in real time.
• Affiliated with OpenAI, Anthropic, Google, or Meta. We're a third party.

How the data is kept honest

Every model in our index carries two things you should look at: a last_verified date and a confidence flag (official or inferred). The changelog tracks pricing changes and verification dates publicly.

Spot a wrong number? Use the report incorrect price link in the footer. Includes auto-filled context for the model and the official docs URL.

Tracked models

Currently 10 frontier models across Anthropic, OpenAI, Google, and Meta. See the full list.

Tech

Static site (Astro + Tailwind). Tokenization runs client-side via tiktoken-class libraries. No analytics cookies. Privacy-respecting traffic counts via Cloudflare Web Analytics.