# Cubic Equation Calculator - 3rd Order Polynomial

> Solve a cubic polynomial ax³ + bx² + cx + d = 0 for all real or complex roots.

Page: https://askcalculators.com/calculator/cubic-equation-3rd-order-polynomial-calculator/
Definition: https://askcalculators.com/calculator/cubic-equation-3rd-order-polynomial-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/cubic-equation-3rd-order-polynomial-calculator/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/cubic-equation-3rd-order-polynomial-calculator/?a=1&b=-6&c=11&d=-6

## Inputs
- a: Coefficient a; type=number; required; default=1
- b: Coefficient b; type=number; required; default=-6
- c: Coefficient c; type=number; required; default=11
- d: Coefficient d; type=number; required; default=-6

## Outputs
- roots: Roots; format=text; primary
- discriminant: Cubic discriminant; format=number
- classification: Root classification; format=text

## Formula
roots solve ax³ + bx² + cx + d = 0 using the depressed-cubic (Cardano) form

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.