Ratio & proportion tools
Mixing Ratio Calculator
Enter a mixing ratio and whichever quantity you already know — the batch total, or one component.
Exact result
600 ml Part A · 150 ml Part B
5 total parts · 1 part = 150 ml · batch 750 ml
- Total parts
- 5
- One part
- 150 ml
- Batch size
- 750 ml
Working
- Add the ratio parts: 5 total parts.
- One part = 750 ÷ 5 = 150 ml.
- Part A = 150 × ratio part = 600 ml.
- Part B = 150 × ratio part = 150 ml.
Mixing is not splitting
| Split | Mix | |
|---|---|---|
| Starting point | A total that already exists | A ratio and one known quantity |
| Question | How is this total shared out? | How much of each component do I add? |
| Total is | Fixed input | Often an output |
| Example | £1,000 split 3:2 | 4:1 mix from the 600 ml you have |
Use the split calculator when the total is given; use this page when you are building the batch.
The arithmetic overlaps, but the direction of travel differs. A split can only ever divide what you already have. A mix can run backwards from a single component to size the whole batch — which is what you usually need when a bottle, not a target volume, is the constraint.
Parts, not halves
4:1 mix
4:1 is five total parts — four of the first component, one of the second.
From a 750 ml batch: one part = 750 ÷ 5 = 150 ml, so 600 ml + 150 ml.
From 600 ml of the first component: one part = 600 ÷ 4 = 150 ml, so add 150 ml and the batch is 750 ml.
From 150 ml of the second component: one part = 150 ml, giving the same 600 ml + 150 ml.
The common mistake is reading 4:1 as “four fifths and a bit” of some other total, or treating a 1:1 mix as one component filling half a container that already holds something. Count the parts first and the rest follows by one multiplication.
Volume and weight are different measurements
A 4:1 ratio measured by volume and a 4:1 ratio measured by weight only produce the same mixture when both components have the same density. A ratio carries no density information, so it cannot convert between the two on its own — 4:1 by weight in millilitres is simply a different mixture from 4:1 by volume.