Random Percentage Generator: One Percent, or 100% Split in Parts: how it works
This random percentage generator draws one whole percent from 0% to 100%, and all 101 values are equally likely. Tap Split 100% and one press cuts 100% into parts that always add up, such as 38% + 31% + 5% + 26% = 100%. Set Split into anywhere from 2 to 12, and raise Smallest part to keep every share above a floor.
How the split stays fair
With Smallest part on 1, four parts need three cuts. The page draws three different cut points from 1 to 99 and takes the gaps: cuts at 38, 69 and 74 give 38, 31, 5 and 26. Every one of the 156,849 ways to write 100 as four whole parts has the same chance, and the parts always add up to 100. A larger Smallest part works the same way on what is left after every part has its floor.
Percent, decimal and fraction
Percent means out of 100, so 35% is 0.35 as a decimal and 35/100, or 7/20, as a fraction. The page draws whole percents only. For tenths, draw 0 to 1000 on the random number page and move the point one place: 374 reads as 37.4%.
Tips
- Rolling a chance such as 30%? Use the pick a number 1 to 100 page: a result of 30 or less means yes. The 101 values here would put the chance slightly off.
- Set Smallest part to 0 and a part may come out as 0%. The opening setting of 1 never gives an empty share.
- To say a percent as odds, divide 100 by it: 25% is 1 in 4 and 5% is 1 in 20.
Questions and answers
How does a percentage randomizer make pie chart data?
Tap Split 100%, set Split into to the number of slices and press. The slices add up to 100 exactly, so the chart needs no rounding fix, and Copy gives the whole sum ready to paste. Open Name the parts to type a label for each slice; the names stay in your browser.
Are the parts of a random split roughly equal?
No. Every split is equally likely, but most are lopsided. With four parts the largest averages about 52% and the smallest about 7%, and in half of all splits one part takes 50% or more. For closer shares, raise Smallest part: at 15, each of four parts lands between 15% and 55%.
Why does 0 to 100 hold 101 values and not 100?
Count both ends: 0, 1, 2 and so on up to 100 makes 101 numbers. That is why 0% and 100% can both come up here. For exactly 100 values, use the pick a number 1 to 100 page.