Ratio & proportion tools
1:3 Ratio Calculator
A 1:3 ratio has 4 total parts, and the first part is 25% of the whole, the second part is 75% of the whole. The ratio is already in its simplest form.
1:3
Simplest form 1:3 · 4 total parts
400
Exact result
100 units · 300 units
25% : 75% · 4 total parts · 1 part = 100 units
first part
second part
- Total parts
- 4
- Simplest form
- 1 : 3
- 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: 100 and 300.
Equivalent 1:3 ratios
- 1 : 3
- 2 : 6
- 3 : 9
- 4 : 12
- 5 : 15
- 6 : 18
What 1:3 means
A 1:3 ratio has 4 total parts. Each part is worth the total divided by 4, so the shares are 25% and 75% of whatever you are dividing.
- Total parts
- 4
- Simplest form
- 1:3
- One part of 400
- 100
Where this ratio shows up
Used for rice and water in many recipes and for one-quarter strength mixes, since one of the four parts is the first quantity.
Worked example
Dividing 400 in a 1:3 ratio gives 100 and 300. Add them back together and you get 400 exactly — a quick way to check any split.