A free, no-login calculator for TypeSafe's Jev that goes beyond tokens x price. It models what actually decides the bill: batching many questions into one call (fan-out), the 1,200 requests/min and 250k tokens/sec ceilings, and the 64k/32k context budget. Every rule is checked against 2,976 real billed requests (code and raw data open on GitHub), and the prices are re-verified against TypeSafe's docs daily. Independent and unofficial.