Ratio & proportion tools
3:1 Ratio Calculator
A 3:1 ratio has 4 total parts, and the first part is 75% of the whole, the second part is 25% of the whole. The ratio is already in its simplest form.
3:1
Simplest form 3:1 · 4 total parts
400
Exact result
300 units · 100 units
75% : 25% · 4 total parts · 1 part = 100 units
first part
second part
- Total parts
- 4
- Simplest form
- 3 : 1
- One part
- 100 units
Know one side instead?
Enter one measured amount to scale the whole ratio.
Working
- Add the parts: 4 total parts.
- One part = 400 ÷ 4 = 100 units.
- Multiply one part by each ratio part: 300 and 100.
Equivalent 3:1 ratios
- 3 : 1
- 6 : 2
- 9 : 3
- 12 : 4
- 15 : 5
- 18 : 6
What 3:1 means
A 3:1 ratio has 4 total parts. Each part is worth the total divided by 4, so the shares are 75% and 25% of whatever you are dividing.
- Total parts
- 4
- Simplest form
- 3:1
- One part of 400
- 100
Where this ratio shows up
Three times as much of the first quantity, typical of sand-to-cement mortar and heavily weighted profit or work splits.
Worked example
Dividing 400 in a 3:1 ratio gives 300 and 100. Add them back together and you get 400 exactly — a quick way to check any split.