Polynomial Long Division Calculator

Enter the dividend and the divisor. Each step divides the leading terms, multiplies back and subtracts, and fractions stay exact (1/2, not 0.5).

Also called: Polynomial division calculator · Algebraic long division calculator

  • Last updated
  • Formula tested against reference values

Your numbers

An expression in x, or coefficients from the highest power down.

Result

P(x) ÷ D(x)
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Calculating…

Quotient Q(x)
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Remainder R(x)
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Does D(x) divide P(x)?
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Full table

How to use this calculator

  1. Enter or choose dividend P(x).
  2. Enter or choose divisor D(x).
  3. The p(x) ÷ D(x) updates as you type. Use Copy result or Share to keep it.

Method

P(x) = D(x)·Q(x) + R(x), with deg R < deg D; each step: next quotient term = (leading term of remainder) ÷ (leading term of D)

P
the dividend
D
the divisor
Q
the quotient
R
the remainder

Worked example

  1. x³ ÷ x = x²; subtract x²(x − 3) = x³ − 3x² to leave x² − 4.
  2. x² ÷ x = x; subtract x(x − 3) = x² − 3x to leave 3x − 4.
  3. 3x ÷ x = 3; subtract 3(x − 3) = 3x − 9 to leave 5, whose degree is below the divisor’s.

(x³ − 2x² − 4) ÷ (x − 3) = x² + x + 3 with remainder 5.

What the result means

A zero remainder means the divisor is a factor of the dividend. The remainder always has a lower degree than the divisor.

Assumptions and limits

  • Coefficients are rational numbers (decimals and fractions are kept exact).
  • One variable (x) only; degree up to 50.

Questions

When should I use synthetic division instead?

Synthetic division is a shortcut that only works for divisors of the form x − r. Long division works for any divisor, such as x² + 1 or 2x + 3.

Do I need to include missing powers?

Not when you type an expression; missing powers are treated as zero. When you list coefficients, include a 0 for each missing power.