÷ Step-by-Step · Remainder · Decimal · Verification

Long Division Calculator

Divide any two numbers and see the full step-by-step long division process — exactly as it's taught in school. Shows quotient, remainder, decimal result, and verification.

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✓ Check: Divisor × Quotient + Remainder = Dividend

How Long Division Works — Step by Step

Long division is the standard method for dividing large numbers by hand. Unlike short division (which works for single-digit divisors), long division shows every step explicitly — making it ideal for learning, checking your work, and understanding exactly how division works. This calculator shows the complete process, just as it's taught in school from 3rd grade through to algebra. For related operations, see our Fraction Calculator and Common Factor Calculator.

The Long Division Formula

Division Relationship
Dividend = Divisor × Quotient + Remainder Quotient = floor(Dividend / Divisor) Remainder = Dividend − (Divisor × Quotient)

The remainder is always less than the divisor. If the remainder is 0, the division is exact (divisor divides evenly into dividend).

The 4 Steps of Long Division (DMSB)

Long division follows a repeating 4-step cycle, sometimes remembered as DMSB: Divide, Multiply, Subtract, Bring down.

Divide

How many times does the divisor go into the current portion of the dividend? Write this digit above the division bracket as part of the quotient. Example: 8 ÷ 7 = 1 (ignore the remainder for now).

Multiply

Multiply the quotient digit by the divisor and write the result below the current dividend portion. Example: 1 × 7 = 7.

Subtract

Subtract the product from the current dividend portion to get the remainder for this step. Example: 8 − 7 = 1.

Bring Down

Bring down the next digit from the dividend and append it to the remainder. Repeat the cycle from Step 1 with this new number. Continue until all digits have been used.

Remainder vs Decimal — What's the Difference?

When a number doesn't divide evenly, you have two ways to express the leftover: as a remainder (an integer left over after division) or as a decimal (continuing the division process past the decimal point). For example, 845 ÷ 7 = 120 remainder 5, or equivalently 120.714285… Both are correct — the format depends on context. In money calculations, decimals make more sense. In problems involving whole objects (people, tiles, boxes), remainders are more meaningful. Our Fraction Calculator can express remainders as fractions (5/7 in this case).

When is Division Exact?

Division is exact (no remainder) when the dividend is a multiple of the divisor — in other words, when the divisor is a factor of the dividend. For example, 999 ÷ 3 = 333 exactly, because 3 is a factor of 999. Use our Common Factor Calculator to find all factors of a number and check divisibility. A quick divisibility check: a number is divisible by 2 if it ends in an even digit; by 3 if its digit sum is divisible by 3; by 5 if it ends in 0 or 5; by 9 if its digit sum is divisible by 9; by 10 if it ends in 0.

Frequently Asked Questions

Common questions about long division, remainders, and how this calculator works

A remainder is the amount left over after division when the dividend cannot be divided evenly by the divisor. For example, 17 ÷ 5 = 3 remainder 2 — because 5 goes into 17 three times (making 15), and 17 − 15 = 2 is left over. The remainder is always a non-negative integer that is strictly less than the divisor. If the remainder is 0, the division is exact. Remainders appear in everyday life: dividing 17 people into teams of 5 gives 3 full teams with 2 people left over. For expressing remainders as fractions, use our Fraction Calculator.
The quotient is how many times the divisor goes completely into the dividend — it's the whole-number result of division. The remainder is what's left over after the divisor has been subtracted as many times as possible. Together they satisfy: Dividend = Divisor × Quotient + Remainder. For 845 ÷ 7: quotient = 120, remainder = 5, because 7 × 120 + 5 = 845. The decimal equivalent combines both: 120 + 5/7 ≈ 120.714. You can verify any division result with the formula above — the calculator shows this check automatically.
With a 2-digit divisor, the process is the same DMSB cycle, but you need to estimate how many times the divisor fits into the current portion of the dividend. For example, 1234 ÷ 56: start with 123 (the first 3 digits). Estimate: 56 × 2 = 112, 56 × 3 = 168 (too big) → quotient digit is 2. Subtract: 123 − 112 = 11. Bring down the 4 → 114. 56 × 2 = 112 → quotient digit is 2. Remainder: 114 − 112 = 2. So 1234 ÷ 56 = 22 remainder 2. Enter any numbers above and the calculator shows every step automatically. Use our Basic Calculator to verify intermediate steps.
Division by zero is undefined in mathematics. There is no number that, when multiplied by zero, gives a non-zero result. In practical terms: you cannot split something into zero groups. If you enter 0 as the divisor, this calculator will display an error message. Mathematically, as a divisor approaches 0, the quotient approaches infinity — which is why some calculators display "∞" or "Error" for division by zero. This is a fundamental rule in arithmetic, algebra, and calculus. In programming, division by zero typically causes a runtime error or returns NaN (Not a Number).
Yes — this calculator supports negative dividends and divisors. The rules for signs are: positive ÷ positive = positive; negative ÷ negative = positive; positive ÷ negative = negative; negative ÷ positive = negative. In other words: same signs → positive quotient; different signs → negative quotient. The long division steps are performed on the absolute values, and the sign is applied to the final quotient. For example, −845 ÷ 7 = −120 remainder −5, and the verification holds: 7 × (−120) + (−5) = −845. For further signed-number operations, try our Scientific Calculator.
To convert a remainder to a decimal, simply continue the long division process past the decimal point. After using all the digits of the dividend, add a decimal point and append zeros, then keep dividing. For example, 845 ÷ 7 = 120 R5: bring down a 0 → 50 ÷ 7 = 7 R1 → bring down 0 → 10 ÷ 7 = 1 R3 → and so on → giving 120.714285714... (repeating). Alternatively, the decimal is simply Quotient + Remainder/Divisor = 120 + 5/7 ≈ 120.7143. Toggle "Decimal" mode in this calculator to see this automatically. Our Fraction Calculator can show the exact fractional form.
DMSB stands for Divide, Multiply, Subtract, Bring down — the four repeating steps of long division. Some teachers use the mnemonic "Does McDonald's Sell Burgers" or "Daddy, Mommy, Sister, Brother" to help students remember the order. The cycle repeats for each digit of the quotient until all digits of the dividend have been processed. The remaining value after the final subtraction is the remainder. This calculator explicitly labels each DMSB step in the step-by-step solution above, making it ideal for homework help, checking classwork, or teaching. See also our Fraction Calculator for dividing fractions using a related approach.