Left side of the ratio A:B.
Right side of the ratio A:B.
A quantity to divide in the ratio A:B (e.g., $700 split 3:4).
Simplified A
3
First part in lowest terms.
Simplified B
4
Second part in lowest terms.
A ÷ B (Decimal)
0.750000
Ratio expressed as a single decimal.
A as % of Total
42.9%
A’s share as a percentage of A+B.
B as % of Total
57.1%
B’s share as a percentage of A+B.
A’s Share
300.00
How much of the total belongs to A.
B’s Share
400.00
How much of the total belongs to B.
GCD is found via the Euclidean algorithm to reduce A:B to lowest terms.
Ratio 3:4 splitting $700.
Ratio
3:4 (already simplified)
Decimal
0.75
A share (42.9%)
$300
B share (57.1%)
$400
Verify
$300 + $400 = $700 ✓
A 3:4 split of $700 gives $300 to A and $400 to B. $300/$400 = 0.75 = 3/4. ✓
This tool takes a two-part ratio (A:B) and reduces it to lowest terms, expresses it as a single decimal, breaks it into percentages, and splits a total quantity proportionally between the two parts. It is the all-in-one tool for working with the "this to that" relationships that show up everywhere.
People use it to mix paint or fuel, scale recipes, divide money or profit between partners, set aspect ratios, and check map scales. Anywhere two quantities need to stay in a fixed proportion, this calculator does the bookkeeping.
A ratio describes a relationship, not specific amounts, so 6:8 and 3:4 mean the same thing. To simplify, the calculator finds the greatest common divisor of the two parts and divides both by it: dividing 6:8 by 2 gives 3:4, the smallest whole-number form.
Reducing a ratio never changes what it represents — it just states it with the cleanest numbers. The decimal form, A ÷ B, is another way to express the same relationship as a single value, which is useful for comparisons.
To divide a total in the ratio A:B, first add the parts to get the number of shares (A + B). Each side then receives its share of the whole: A gets Total × A ÷ (A + B), and B gets the rest. The two amounts always sum back to the original total.
For example, a 3:4 split has 7 shares, so the first part is 3/7 of the total and the second is 4/7. The calculator also shows these as percentages, which makes uneven splits easy to explain.
A fraction compares a part to a whole, while a ratio compares two separate parts to each other. The ratio 3:4 does not mean three-quarters; it means that for every 3 units of one thing there are 4 of another, for 7 units in total.
Mixing these up is the most common mistake. If you treat 3:4 as the fraction 3/4 when splitting money, you will hand out the wrong amounts. Convert the ratio to part-of-whole fractions (3/7 and 4/7) before dividing a total.
Split $1,000 in a 2:3 ratio. The parts add to 5 shares, so the first side gets 2/5 of the money, 1,000 × 2 ÷ 5 = $400, and the second gets 3/5, which is $600. As percentages that is 40% and 60%, and the two amounts add back to $1,000.
Check it with the simplified ratio: 400:600 reduces by 200 to 2:3, the proportion you started with. Whenever the shares simplify back to the original ratio, you know the split is correct.
This calculator handles two-part ratios only. For three or more parts, such as A:B:C, split in stages — first separate one part, then divide the remainder in the ratio of the others.
Both values are treated as positive, and the greatest-common-divisor simplification is exact only for whole numbers. Decimal inputs still produce correct splits and percentages, but the reduced "lowest terms" form is most meaningful when the parts are integers.
Dividing both sides by GCD. 6:9 simplifies to 2:3 (GCD=3). The relationship is unchanged — just expressed with smaller numbers.
A fraction (3/4) is part of a whole. A ratio (3:4) compares two separate quantities — they don’t need to add to any particular total.
Multiply both sides by the same number. 3:4 scaled by 5 is 15:20, still equivalent to 3:4.
Yes. 1.5:2 is valid and equivalent to 3:4. This calculator handles decimal inputs but the GCD simplification is most accurate for integers.
Add the ratio parts to get the total number of shares, then give each side its fraction of the whole. To split $1,000 in a 2:3 ratio, the total is 5 shares, so one side gets 2/5 ($400) and the other 3/5 ($600). The shares always add back to the original total.
A ratio of A:B can be read as the fraction A/(A+B) of the whole for the first part. For 2:3, the first part is 2/5 = 40% and the second is 3/5 = 60%. Converting to a percentage is often the easiest way to communicate a ratio to others.
Keep the ratio between ingredients fixed while changing the totals. If a recipe uses flour and sugar in a 3:1 ratio, doubling it becomes 6:2 — still 3:1 when simplified. Scaling preserves the proportion, so the result tastes the same at any size.
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Note
This calculator is an educational tool. For graded coursework, exams, or professional work, double-check the method and rounding against your own requirements.
Built and maintained by Calculator Matters, an independent calculator project. Method checked against published formulas and primary sources · Last reviewed 3 June 2026 · How we calculate · Found an error? corrections@calculatormatters.com