# How to track LLM cost on Gemini > Gemini can be reached through its native API or an OpenAI-compatible endpoint. The two carry usage in different fields, so check which yours uses. URL: https://getculpa.com/track-llm-cost-gemini Last reviewed: 2026-08-02 ## Answer Gemini can be reached two ways, through its native API or through an OpenAI-compatible endpoint, and the two carry usage in different fields. Culpa, a local-first LLM cost, margin, and forecast ledger, reads whichever shape arrives, and the route you chose decides which counts are available to price, thinking tokens most of all. ## Why this happens Most providers offer one response shape. Gemini offers two doors into the same models, and they don't describe usage the same way. The native shape carries a usage block with its own field names, including a count for thinking tokens and a model version that can differ from what you asked for. The compatible endpoint speaks the OpenAI shape instead. Whether a given field survives that translation is a property of the endpoint rather than of your ledger, which makes it something to check rather than assume. ## What this usually looks like - Nobody can say which Gemini endpoint your application actually calls. - You run a thinking model and no reasoning-token count appears anywhere in your data. - Streamed Gemini responses parse inconsistently across your tooling. - Your Gemini costs reconcile on short prompts and drift on long or reasoning-heavy ones. ## Common mistakes - Assuming both Gemini routes report identical usage detail. Why it hurts: They carry different field names, and a field that never arrives can't be priced by anyone. Do instead: Check a real response from your own route and list which counts it actually contains. - Ignoring thinking tokens on a reasoning model. Why it hurts: They bill like output while never reaching a user, so leaving them out understates the expensive half. Do instead: Confirm a reasoning count reaches your ledger, and if it doesn't, reconcile against the invoice to size it. - Expecting Gemini caching to bill like Anthropic caching. Why it hurts: Gemini charges for storage time rather than for written tokens, so no token count can represent it. Do instead: Track cache storage as its own line. It's real spend that token accounting structurally can't see. ## Self-check - Find which endpoint your client is configured against and write it down. - Take one real response and list every usage field it carries. - On a reasoning model, check whether a thinking-token count is among them. - Reconcile a month of Gemini spend against the invoice and note where the drift concentrates. - Check whether you're paying for cache storage that no token figure represents. ## What thinking tokens do to a reconciliation (illustrative) A reasoning workload on Gemini 2.5 Pro at real rates of $1.25 per million input and $10.00 output, sending 10 million prompt tokens and producing 4 million tokens of visible answer plus 6 million thinking tokens in a month. Volumes are modelled. Input: 10 x $1.25 = $12.50 Visible output alone: 4 x $10.00 = $40.00, for a recorded total of $52.50 Output including thinking tokens: 10 x $10.00 = $100.00, for a real total of $112.50 A ledger holding only the visible answer reads $52.50 against a $112.50 invoice The missing 6 million tokens are 53% of the bill and none of them reached a user Over half the spend can sit in tokens nobody reads. Whether your route reports them is the difference between a reconciliation that closes and one that drifts by more than the visible answer costs. ## Cost figures Every figure carries its confidence and its source. No figure on this site is provider-reported. - $52.50 to $112.50 — modelled monthly Gemini cost recorded from visible output alone against the full billed total [estimated] Source: Both endpoints at real Gemini 2.5 Pro rates per million from the price book, effective 2026-07-02. A range because the token volumes and the thinking share are modelled. - 53% — modelled share of a reasoning workload's bill sitting in tokens no user ever sees [calculated] Source: $60.00 of thinking-token output divided by the $112.50 modelled total, from the teardown arithmetic. ## FAQ Q: Which Gemini endpoint should I point Culpa at? A: Either works, and the practical question is which usage fields your traffic needs. If you run reasoning models, confirm that a thinking-token count reaches your ledger on the route you picked, because that's where the largest share of an unreconciled bill tends to hide. Q: Do Gemini thinking tokens cost money? A: They bill as output on the providers in this price book, so on a model where output costs eight times input they're expensive and invisible at the same time. A user never sees them, which is exactly why they go uncounted. Q: How does Gemini cache billing differ? A: Gemini charges for how long cached content is stored rather than for the tokens written into it. That's a real cost with no token count behind it, so it belongs on its own line rather than inside a per-token figure. ## Sources - Culpa docs: connect your providers: https://app.getculpa.com/docs/how-to/connect-your-providers - Gemini API pricing: https://ai.google.dev/gemini-api/docs/pricing Run the free Cost Leak Scan: https://app.getculpa.com/scan?source=pseo&slug=track-llm-cost-gemini&cluster=integration Machine-readable index of every guide: https://getculpa.com/api/pages Human-readable index of every guide: https://getculpa.com/guides Site overview: https://app.getculpa.com/llms.txt Privacy: Culpa runs on your infrastructure. Your prompts and responses never leave it. Culpa counts calls to run your plan, and it fails open, so if it ever breaks your app keeps running.