Ratio Calculator
Solve A : B = C : D for the missing term, simplify or compare ratios, and enlarge or shrink a ratio.
Change the values and press Calculate to work out your own figures.
Solve a proportion A : B = C : D
Enter three of the four terms and leave the missing one empty.
Show the working
- Cross-multiply: a × d = b × c
- Solve for the blank: 800
Simplify a ratio
Enter the two terms.
Show the working
- Scale to whole numbers, then divide both by their greatest common factor
Compare two ratios
Enter both ratios.
Show the working
- Compare a ÷ b with c ÷ d
Enlarge or shrink a ratio
Enter the ratio, enlarge or shrink, and how many times.
Show the working
- Multiply both terms by 0.4
How to use it
Enter three of the four terms and leave the missing one empty. Enter the two terms. Enter both ratios. Enter the ratio, enlarge or shrink, and how many times.
Numbers can be whole numbers, decimals (0.75), fractions (3/4), mixed numbers (1 1/2), repeating decimals (0.(3)) and, where a percent is asked for, percentages (75%). Show the working gives each step.
Key facts
A : B = C : D ⇔ A × D = B × C
Scaling screens and images
A 16 : 9 screen enlarged 120 times is 1,920 : 1,080, which is full HD.
Questions
If 3 : 4 = 600 : x, what is x?
800.
Simplify 12 : 18.
2 : 3.
Formulas
A : B = C : D ⇔ A × D = B × C
Sources
Limitations
- Numbers have at most 120 digits.