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finmath Cost Basis Calculator
x402
finmath Cost Basis Calculator is a paid API for AI agents from finmath.qzqh5rrbkz.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).
Computes cost basis for cryptocurrency or asset lots using configurable accounting methods (FIFO, LIFO, HIFO, etc.) given purchase lots and a sale quantity
Price / call$0.002
Success—
StatusUnknown
How this service works
Deterministic finance and crypto math for AI agents: TradFi (NPV, IRR, XIRR, Black-Scholes + Greeks, bonds, VaR, Sharpe) and DeFi (impermanent loss, perp liquidation, funding, Uniswap v3, health factor, cost basis). Exact, model-free arithmetic that LLMs get wrong — priced per call in USDC.
Output
Returns the computed cost basis result including lot allocations used, total cost basis amount, and metadata about the calculation method applied.
Example use cases
Example prompt
“Calculate the FIFO cost basis for selling 1.5 ETH — I bought 1 ETH at $1,800 on Jan 5, then 1 ETH at $2,200 on Mar 10, and now I'm selling 1.5 ETH.”
Technical details
Endpoint
POSThttps://finmath.qzqh5rrbkz.workers.dev/v1/cost_basisWhen to prefer
Use this endpoint when you need deterministic, exact cost basis arithmetic for tax reporting or portfolio tracking — especially for crypto assets where LLMs are known to make arithmetic errors. Prefer this over manual calculation or LLM reasoning when precision matters for FIFO/LIFO/HIFO lot matching or when computing realized gains for tax purposes.
Side effects
- Missing required 'lots' array — returns validation error
- Missing required 'sell_qty' — returns validation error
- sell_qty exceeds total available quantity in lots — returns error or partial fill
- Invalid method string — may default to FIFO or return error
- Malformed lot objects missing price or quantity fields — returns parsing error
- Payment not provided or insufficient USDC — returns 402 Payment Required
Input
{
"lots": [
{
"quantity": 1,
"cost_per_unit": 1800
},
{
"quantity": 1,
"cost_per_unit": 2200
}
],
"method": "FIFO",
"sell_qty": 1.5
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| lotsrequired | array | lots |
| method | string | method |
| sell_qtyrequired | number | sell_qty |
Output
{
"meta": {
"tool": "cost_basis",
"disclaimer": "Deterministic calculation utility. Not financial, investment, or trading advice.",
"deterministic": true
},
"result": {
"method": "FIFO",
"avg_cost": null,
"cost_basis": null,
"consumed_lots": [
{
"qty": null
},
{
"qty": null
}
],
"remaining_lots": []
}
}Schema · Response
| Field | Type | Description |
|---|---|---|
| metarequired | object | |
| resultrequired | — |
Tags
x402
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