15 Free Tools
Built for AI developers and product teams. 15 tools covering API costs, agent calculators, agentic loop estimation, memory costs, automation comparisons, and full stack cost building — instant results, no sign-up.
Agent Calculators
True cost of running AI agents at scale — per task, per loop, per month.
Stack Builder & Comparisons
Build your full AI product stack and compare automation platforms side by side.
Nearly every unexpectedly large AI bill traces back to the same misunderstanding: people price a feature using the input cost and forget that output tokens typically cost three to five times more, and that conversational applications resend the entire history on every single turn.
That second point is the expensive one. In a chat interface, turn 20 does not send one message — it sends all twenty. Token consumption grows roughly with the square of conversation length, which is why a prototype that costs pennies in testing can cost hundreds of dollars a day once real users hold long conversations with it.
| Lever | Typical impact | Trade-off |
|---|---|---|
| Prompt caching | Up to ~90% off repeated input tokens | Only helps with a stable prefix (system prompt, docs) |
| Batch processing | Around 50% off | Results arrive within hours, not seconds |
| Routing simple calls to a smaller model | 10–20× cheaper per token | Requires classifying difficulty up front |
| Trimming conversation history | Scales with how aggressively you trim | The model loses earlier context |
| Capping max output tokens | Directly bounds the expensive side | Long answers get truncated |
| Retrieval instead of long context | Often 5–10× cheaper | Adds retrieval infrastructure to build and maintain |
A workable estimate needs four numbers, and most teams only guess at the third and fourth:
A rough rule for English text: one token is about four characters, or roughly 0.75 words. A 500-word document is therefore about 665 tokens. Use the token calculator for a real count rather than that approximation when the numbers matter, and the API cost calculator to turn those counts into a monthly figure.
A single completion is one request. An agent that plans, calls tools, reads results, and iterates might make fifteen model calls to complete one user-visible task — and each of those calls carries the accumulated context of every previous step. Budgeting an agent as though it were a chatbot understates the cost by an order of magnitude, which is what the agent cost calculator and agentic loop estimator exist to correct.
Model pricing moves frequently, and providers add and retire models regularly. We update these calculators when published rates change, but always confirm current pricing on the provider's own pricing page before committing to a budget or signing a contract.
What is a token, in practical terms?
A token is the chunk of text a model actually processes — usually a word fragment rather than a whole word. In English, one token averages about four characters or 0.75 words, so 1,000 tokens is roughly 750 words. Code, punctuation-heavy text, and non-English languages tokenize less efficiently and consume more tokens per word.
Why is output more expensive than input?
Input tokens are processed in parallel in a single forward pass. Output tokens are generated one at a time, each requiring a full pass through the model that depends on every token before it. That sequential generation is far more computationally expensive, and pricing reflects it — output typically runs three to five times the input rate.
How much does prompt caching actually save?
It depends entirely on how much of your prompt is stable. If a long system prompt or document set is identical on every request, caching can cut that portion of input cost by up to about 90%. If each request is unique, caching saves nothing and may add a small write cost. It works best for document Q&A and agents with large fixed instructions.
Is a subscription or the API cheaper for my use case?
Subscriptions win for interactive human use with unpredictable volume; the API wins for programmatic, high-volume, or automated work. The crossover depends on your actual token throughput — the subscription ROI calculator compares both against your real numbers rather than a generic assumption.
Do these calculators use live pricing?
No — rates are hardcoded from providers' published pricing pages and updated when those change. This keeps the tools fast and fully client-side, but it means you should verify against the provider's current pricing before making a financial commitment.
Why did my costs jump without traffic increasing?
The usual causes are longer conversations (context grows with each turn), a change in system prompt length that applies to every request, retrieval returning more documents than before, or a model swap to a higher-priced tier. Check average input tokens per request over time — that metric usually reveals it immediately.
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