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

# Calculate Internal Rate of Return (IRR)

> Calculate the Internal Rate of Return - the discount rate that makes the net present value of all cash flows equal to zero. IRR is widely used in capital budgeting, project evaluation, and investment analysis to assess the profitability of potential investments. It represents the effective annualized rate of return. For evenly-spaced cash flows, optionally provide times array; otherwise, assumes annual periods. [Tier: STANDARD, Credits: 2]



## OpenAPI

````yaml api-specs/solver.json post /quantlib/solver/finance/irr
openapi: 3.1.0
info:
  title: FinceptQuantLib API - Solver
  description: >-
    Solver module endpoints for FinceptQuantLib API. The Solver module (Basic
    Tier, 1 credit per request) provides advanced financial solvers including
    bond analytics (yield, duration, convexity), implied volatility
    calculations, spread computations (Z-spread, ASW, OAS), curve bootstrapping,
    interest rate conversions, and model calibration (Vasicek, CIR). Essential
    for fixed income analysis, derivatives pricing, and risk management.
  version: 3.0.0
  contact:
    name: Fincept API Support
    url: https://fincept.in
servers:
  - url: https://api.fincept.in
    description: Fincept API Production Server
security:
  - APIKeyHeader: []
tags:
  - name: quantlib-solver
    description: >-
      Advanced financial solvers for bond analytics, implied volatility, spread
      calculations, and model calibration
    x-displayName: Solver
paths:
  /quantlib/solver/finance/irr:
    post:
      tags:
        - quantlib-solver
      summary: Calculate Internal Rate of Return (IRR)
      description: >-
        Calculate the Internal Rate of Return - the discount rate that makes the
        net present value of all cash flows equal to zero. IRR is widely used in
        capital budgeting, project evaluation, and investment analysis to assess
        the profitability of potential investments. It represents the effective
        annualized rate of return. For evenly-spaced cash flows, optionally
        provide times array; otherwise, assumes annual periods. [Tier: STANDARD,
        Credits: 2]
      operationId: irr
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - cashflows
              properties:
                cashflows:
                  type: array
                  description: >-
                    Array of cash flows (negative for outflows, positive for
                    inflows)
                  items:
                    type: number
                  example:
                    - -100000
                    - 30000
                    - 35000
                    - 40000
                    - 45000
                times:
                  type: array
                  description: >-
                    Optional array of times in years for each cash flow (if not
                    provided, assumes annual periods starting at 0)
                  items:
                    type: number
                  example:
                    - 0
                    - 1
                    - 2
                    - 3
                    - 4
                guess:
                  type: number
                  description: Initial guess for the IRR solver
                  default: 0.1
                  example: 0.1
            example:
              cashflows:
                - -100000
                - 30000
                - 35000
                - 40000
                - 45000
              times:
                - 0
                - 1
                - 2
                - 3
                - 4
              guess: 0.1
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      irr:
                        type: number
                        description: The calculated internal rate of return as a decimal
                        example: 0.1867
              example:
                success: true
                data:
                  irr: 0.1867
        '401':
          $ref: '#/components/responses/UnauthorizedError'
        '402':
          $ref: '#/components/responses/InsufficientTierError'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                type: object
                properties:
                  detail:
                    type: array
                    items:
                      type: object
      security:
        - APIKeyHeader: []
components:
  responses:
    UnauthorizedError:
      description: Authentication information is missing or invalid
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Invalid API key
    InsufficientTierError:
      description: API tier insufficient for this endpoint
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Endpoint requires Basic tier or higher
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      in: header
      name: X-API-Key
      description: >-
        API key for authentication. Get your key at
        https://api.fincept.in/auth/register

````