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Last updated: July 31, 2026

General to Standard Form Circle Calculator

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Formula

h = -D/2, k = -E/2, r² = h² + k² - F

Where:

  • D=D coefficient
  • E=E coefficient
  • F=F constant
General to Standard Form of a CircleAn arrow diagram showing the general form equation being converted via completing the square into the standard form equation, revealing the center and radius.General Formx² + y² + Dx + Ey + F = 0complete the squareStandard Form(x-h)² + (y-k)² = r²(h, k)r
h = -D/2, k = -E/2, and r = √(h² + k² - F) reveal the circle's center and radius.

Worked Examples

Valid real circle

Convert D=-6, E=4, F=-12.

  1. 1h=3, k=-2
  2. 2r²=3²+(-2)²-(-12)=25
  3. 3r=5 and circle is real
Final Answer: h=3, k=-2, radiusSquared=25, r=5, isRealCircle=true

Origin-centered form

Convert D=0, E=0, F=-49.

  1. 1h=0 and k=0
  2. 2r²=49
  3. 3r=7
Final Answer: h=0, k=0, radiusSquared=49, r=7, isRealCircle=true

Non-real case

Convert D=2, E=2, F=10.

  1. 1h=-1 and k=-1
  2. 2r²=1+1-10=-8
  3. 3Negative r² means no real circle
Final Answer: h=-1, k=-1, radiusSquared=-8, r=0, isRealCircle=false

Introduction

Completing the square transforms general-form circle equations into center-radius form and reveals whether a real circle exists.

Formula and Method

General to Standard Form Circle Calculator applies h = -D/2, k = -E/2, r² = h² + k² - F and returns deterministic outputs from validated inputs.

  • Validate each required input

  • Apply the stated formula

  • Round numeric outputs where needed

  • Return safe defaults when validation fails

Input Fields

Use these keys exactly as defined in calculation.ts.

  1. 1

    D: D coefficient

  2. 2

    E: E coefficient

  3. 3

    F: F constant

Output Fields

These values map directly to calculation.ts return keys.

  1. 1

    h: x-coordinate of center

  2. 2

    k: y-coordinate of center

  3. 3

    radiusSquared: Computed r² value

  4. 4

    r: Positive radius when r² > 0

  5. 5

    isRealCircle: String flag: true or false

Validation Rules

D, E, and F must be finite; negative or zero radius-squared yields non-real/degenerate status.

  • Finite numeric values are required

  • Domain restrictions are enforced before solving

  • Invalid input returns default-safe outputs

  • Check examples to confirm expected behavior

How to Use This Calculator

Enter inputs, run the calculation, and read the primary output first.

  • Enter all required values

  • Click calculate

  • Review primary output first

  • Use supporting outputs for interpretation

Practical Uses

This calculator is useful for study, verification, and fast applied math checks.

  • Equation conversion drills

  • Graphing preparation

  • Conic classification

  • Algebra completion-of-square checks

FAQs

What does the General to Standard Form Circle Calculator compute?

It computes Center h and supporting outputs from your inputs.

Which inputs are required?

Required inputs are: D coefficient, E coefficient, F constant.

How are invalid inputs handled?

When validation fails, the calculator returns safe default values and does not attempt invalid math.

Are results rounded?

Yes. Numeric outputs are rounded inside calculation.ts (typically to 6 decimal places).

Can I use negative or decimal values?

All finite coefficients are accepted; real radius exists only when radiusSquared > 0.

How should I verify my answer?

Use the worked examples and compare each output key with your manual steps.