> ## Documentation Index
> Fetch the complete documentation index at: https://docs.easierprop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Lot calculator

> Calculate the appropriate lot size based on risk in dollars and stop loss distance in points.



## OpenAPI

````yaml /openapi-spec/easierprop.yaml post /api/accounts/{id}/lot-calculator
openapi: 3.0.3
info:
  title: Easier Prop REST API
  version: 2.1.0
  description: >
    MT5 Trading Infrastructure API. Manage multiple broker accounts, execute
    trades, stream market data, and administer API keys, usage snapshots, and
    billing terms.


    **Client API** endpoints live under `/api` and require an `X-API-Key`
    header.

    **Admin API** endpoints live under `/admin` and accept either a JWT
    `Authorization: Bearer <jwt>` (obtained via `/admin/login`) or the same
    `X-API-Key` header used by client endpoints.


    Admin user provisioning is read-only via REST: `GET /admin/admins` lists
    admins, but creation, update, and deletion are performed out-of-band (DB /
    ops tooling). Bootstrap a brand-new deployment with `POST /admin/seed` while
    no superadmin exists.
servers:
  - url: https://api.easierprop.com
    description: Production
security: []
tags:
  - name: Admin
    description: Authentication, API key management, and admin user CRUD
  - name: Accounts
    description: Register and manage MT5 broker accounts
  - name: Sessions
    description: Control broker connections
  - name: Trading
    description: Place, modify, and close orders
  - name: Account Info
    description: Balance, equity, margin, and statistics
  - name: Market Data
    description: Symbols, quotes, OHLC history, and trade sessions
  - name: Expert Advisors
    description: Upload, run, stop, and monitor MQL5 Expert Advisors on your accounts
  - name: Enhanced
    description: >-
      Portfolio, risk, performance, copy-trade, hedge, breakeven, close-all, lot
      calculator, and position details
  - name: Extended
    description: >-
      Change password, server timezone, symbol sessions, closed positions,
      mails, tick value, equity stats, and more
paths:
  /api/accounts/{id}/lot-calculator:
    parameters:
      - $ref: '#/components/parameters/accountId'
    post:
      tags:
        - Enhanced
      summary: Lot calculator
      description: >-
        Calculate the appropriate lot size based on risk in dollars and stop
        loss distance in points.
      operationId: lotCalculator
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - symbol
                - side
                - risk_dollars
                - sl_points
              properties:
                symbol:
                  type: string
                  example: EURUSD
                side:
                  type: string
                  enum:
                    - buy
                    - sell
                  example: buy
                risk_dollars:
                  type: number
                  description: Maximum risk amount in account currency
                  example: 100
                sl_points:
                  type: number
                  description: Stop loss distance in points
                  example: 100
      responses:
        '200':
          description: Lot calculation result
          content:
            application/json:
              schema:
                type: object
                properties:
                  ok:
                    type: boolean
                    example: true
                  data:
                    $ref: '#/components/schemas/LotCalculation'
      security:
        - ApiKeyHeader: []
components:
  parameters:
    accountId:
      name: id
      in: path
      required: true
      schema:
        type: string
        format: uuid
      description: Account ID
  schemas:
    LotCalculation:
      type: object
      properties:
        symbol:
          type: string
          example: EURUSD
        lots:
          type: number
          example: 0.1
        risk_dollars:
          type: number
          example: 100
        sl_points:
          type: number
          example: 100
        contract_size:
          type: number
          example: 100000
        tick_value:
          type: number
          example: 1
        tick_size:
          type: number
          example: 0.00001
        digits:
          type: integer
          example: 5
        current_price:
          type: number
          example: 1.08542
        value_per_point:
          type: number
          example: 1
  securitySchemes:
    ApiKeyHeader:
      type: apiKey
      in: header
      name: X-API-Key
      description: |
        Client API key (prefixed with `sk_`). On `/api/*` endpoints the key
        is scoped to its own MT5 accounts. On `/admin/*` endpoints the key
        identifies its **owning admin** and grants access to all of that
        admin's keys — so any of your `sk_` works to manage any of your
        other keys (cross-admin operations are rejected as `400 Key not
        found`).

````