Ratio of 12 to 21 (12:21)

Ratio of 12 to 21

A ratio of 12 to 21 can be written as 12 to 21, 12:21, or 12/21. Furthermore, 12 and 21 can be the quantity or measurement of anything, such as students, fruit, weights, heights, speed and so on.

A ratio of 12 to 21 simply means that for every 12 of something, there are 21 of something else, with a total of 33.

In the box below, you can enter a number in either box and we will calculate the other number to keep the ratio of 12 to 21. In other words, we will calculate the corresponding equivalent ratio of 12:21 for you.

To calculate the left side of the ratio, our calculator multiplies the right side by 12 and then divides the product by 21. To calculate the right side of the ratio, our calculator multiplies the left side by 21 and then divides the product by 12. Answers are rounded to two decimals if necessary.

Below is a list of equivalent ratios of 12:21 that we created using our 12:21 ratio calculator above.

4:7

8:14

12:21

16:28

20:35

24:42

28:49

32:56

36:63

40:70

44:77

48:84

We have also created a pie chart for you to put 12:21 ratio in perspective. To do so, we divided a pie into 33 pieces and then colored 12 pieces green and 21 pieces blue. The pie will look exactly the same using any equivalent ratio of 12:21.

12 to 21 pie ratio

The green part of the pie covers 36.36% and the blue part covers 63.64%. To calculate the percentages, we divided each side of the ratio by its total and then multiplied by 100, like this:

(12 / 33)×100 ≈ 36.36
(21 / 33)×100 ≈ 63.64

In fractional terms, 12/21 of the pie above is colored in green. This means that the ratio of 12 to 21 or 12:21 can also be expressed as a fraction, where the 12 to the left of the colon is the numerator and the 21 to the right of the colon is the denominator:

12:21 = 12/21

Ratio is often used when defining rectangles in width:height format. Width and height can be feet, inches, centimeters, or any other kind of length. With a ratio of 12 to 21, the width is 12 and the height is 21. Below is a picture of what a rectangle with a ratio of 12:21 looks like.

12 to 21 pie rectangle

Since the simplest form of the fraction 12/21 is 4/7, the simplest form of the ratio 12:21 is also 4:7.

Ratio Calculator
Need information about another ratio? Here you can submit another ratio for us to explain.

Ratio of 12 to 22
Go to the next ratio on our list that we have detailed information about.