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Dilution Ratio Calculator

Concentrate and water for any dilution ratio.

Your measurementsEvery assumption editable01

The finished volume you want to fill.

The N in 1:N. A 1:10 dilution is ten parts water to one of concentrate.

DilutionCalculated live02

Result

2.91oz concentrate

2.91 oz concentrate topped up to 32 oz

Ratio11 parts in total
1 : 10
Concentrate9.091% of the finished volume
2.909 oz
Water
29.091 oz
Finished volume
32 oz
Per US gallonconcentrate per 128 oz of finished solution
11.636 oz

A 1:10 dilution means one part concentrate to ten parts water — eleven parts in total, not ten. That off-by-one is why the same label produces two different mixes depending on who read it, and the difference grows as the ratio tightens.

Add concentrate to water rather than the reverse, particularly with anything acidic. It is the safer order and it disperses more evenly.

The per-gallon figure is the practical one for a sprayer or a bucket, since most concentrate labels quote ounces per gallon rather than a ratio.

A 1:10 dilution is one part concentrate to ten parts water — eleven parts in total, not ten. That off-by-one is why the same label produces two different mixes depending on who read it, and the error grows as ratios tighten.

Why use this tool?What it does differently03

Why use this tool?

The off-by-one handled

1:10 is one part in eleven. Treating it as one in ten makes the mix ten per cent strong.

Ounces per gallon

The figure most concentrate labels actually quote, alongside the container split.

Any container size

Spray bottle, bucket or tank.

Order of addition

Concentrate into water, not the reverse — safer and it disperses better.

How this worksThe method04

How this dilution ratio calculator works

A ratio of 1:N means one part concentrate to N parts water, so the total is N + 1 parts. Concentrate is the container volume divided by that total, and water is the remainder.

The commonest error is dividing by N rather than N + 1. At 1:10 that makes the mix about ten per cent stronger than intended, and at tighter ratios like 1:4 the error grows to twenty-five per cent.

The per-gallon figure is given because most concentrate labels quote ounces per gallon rather than a ratio, and converting between the two in your head is where mistakes creep in.

How to use itStep by step05

How to use it

  1. Step 1: Enter the container size

    The finished volume you want to end up with.

  2. Step 2: Enter the ratio

    The N in 1:N — 10 for a 1:10 dilution.

  3. Step 3: Measure the concentrate first

    Into the container, then top up with water.

  4. Step 4: Add concentrate to water

    Not the other way round, particularly with anything acidic.

Example usageWorked figures06

Example usage

A spray bottle at 1:10
A 32 oz bottle needs 2.91 oz of concentrate topped up to 32 oz — that is 9.09% of the finished volume, and 11.64 oz per gallon.
The off-by-one error
Treating 1:10 as one tenth would give 3.2 oz rather than 2.91 — about ten per cent too strong, every time.
A strong mix
1:4 in the same bottle is 6.4 oz of concentrate. At tight ratios the off-by-one error grows to a quarter.
Frequently asked questionsCommon questions07

Frequently asked questions

What does a 1:10 dilution mean?

One part concentrate to ten parts water — eleven parts in total. So concentrate is one eleventh of the finished volume, not one tenth.

How much concentrate for a 32 oz bottle at 1:10?

2.91 oz, topped up to 32 oz with water. That is 9.09 per cent of the finished volume.

How do I convert a ratio to ounces per gallon?

Divide 128 by the total number of parts. At 1:10 that is 128 ÷ 11, or about 11.64 oz per gallon.

Should I add water or concentrate first?

Put the water in first and add concentrate to it. It is the safer order with anything acidic and it disperses more evenly.

Is dilution the same as a mixing ratio?

No. Dilution measures concentrate against water; a two-part mixing ratio measures components against each other and they sum to the total. The two calculations differ.

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