A printed ratio such as 1:10 has two common meanings. It can mean 1 part concentrate in 10 parts of finished solution (parts per total). It can also mean 1 part concentrate plus 10 parts water (parts per water). The first gives 10% concentrate, and the second gives about 9.09%. Read the label's wording before you use any number from the table below.
Which convention does your label use?
Find the sentence on the label that defines the ratio, and match it to one of these two readings.
- Parts per total (concentrate : finished solution). Typical wording: "1 part product to 10 parts solution," "makes 10 gallons per gallon," or "1 gal per 10 gal of use solution." The concentrate fraction is 1/N.
- Parts per water (concentrate : water). Typical wording: "1 part product to 10 parts water" or "mix 1 gal with 10 gal water." The concentrate fraction is 1/(N+1).
- Fluid ounces per gallon. Wording such as "4 fl oz per gallon" does not use a ratio at all. The concentrate fraction is fl oz ÷ 128, because a US gallon is 128 fluid ounces.
The ratio alone cannot tell you the convention. 1:10 is not convertible until you know which reading applies. If the label gives only the bare ratio, check the label's mixing example, the dispenser instructions, or the manufacturer's technical data sheet. If none of those state the convention, ask the manufacturer.
Ounces on a label are normally fluid (volume) ounces. Weight ounces measure mass, and a concentrate's density is rarely 1.0. Do not substitute one for the other unless the label gives a weight-based instruction.
Formulas
Let N be the second number in a printed "1:N" ratio. All volumes are US gallons, and 1 gal = 128 fl oz.
Parts per total:
[ \text{concentrate fraction} = \frac{1}{N}, \qquad \text{finished gal per 1 gal concentrate} = N, \qquad \text{fl oz concentrate per finished gal} = \frac{128}{N} ]
Parts per water:
[ \text{concentrate fraction} = \frac{1}{N+1}, \qquad \text{finished gal per 1 gal concentrate} = N+1, \qquad \text{fl oz concentrate per finished gal} = \frac{128}{N+1} ]
To convert between the two conventions for the same actual mix:
[ N_{\text{total}} = N_{\text{water}} + 1 ]
Both formulas treat concentrate and water volumes as additive. Real mixes can differ slightly, but a label's stated convention defines the intended dose, so use that definition.
Lookup table: concentrate share and finished volume
| Printed ratio | Convention | Concentrate fraction | Water fraction | Finished gal per 1 gal concentrate | Concentrate per finished gal (fl oz) |
|---|---|---|---|---|---|
| 1:4 | Per total | 25% | 75% | 4 | 32 |
| 1:4 | Per water | 20% | 80% | 5 | 25.6 |
| 1:8 | Per total | 12.5% | 87.5% | 8 | 16 |
| 1:8 | Per water | 11.11% | 88.89% | 9 | 14.22 |
| 1:10 | Per total | 10% | 90% | 10 | 12.8 |
| 1:10 | Per water | 9.09% | 90.91% | 11 | 11.64 |
| 1:16 | Per total | 6.25% | 93.75% | 16 | 8 |
| 1:16 | Per water | 5.88% | 94.12% | 17 | 7.53 |
| 1:32 | Per total | 3.125% | 96.875% | 32 | 4 |
| 1:32 | Per water | 3.03% | 96.97% | 33 | 3.88 |
| 1:64 | Per total | 1.5625% | 98.4375% | 64 | 2 |
| 1:64 | Per water | 1.54% | 98.46% | 65 | 1.97 |
| 1:128 | Per total | 0.78125% | 99.21875% | 128 | 1 |
| 1:128 | Per water | 0.78% | 99.22% | 129 | 0.99 |
The ratios in this table are generic arithmetic examples. They are not product strengths, and no product is implied to use any of them. Percentages here are volume percent of concentrate in the finished solution, not weight percent and not the active-ingredient concentration. A concentrate's active-ingredient content is a separate figure, typically listed on the label or in SDS Section 3.
Worked example: same printed ratio, different batch
All values here are assumed. Take a label that prints 1:10 and a 5-gallon batch.
- Per total. Concentrate = 5 gal ÷ 10 = 0.5 gal = 64 fl oz. Water = 5 − 0.5 = 4.5 gal. Check: 64 ÷ 128 = 0.5 gal, and 0.5 ÷ 5 = 10%.
- Per water. Concentrate = 5 gal ÷ 11 = 0.4545 gal = 58.18 fl oz. Water = 5 − 0.4545 = 4.5455 gal. Check: 58.18 ÷ 128 = 0.4545 gal, and 0.4545 ÷ 5 = 9.09%.
Misreading a per-water label as per total puts about 5.82 fl oz too much concentrate in a 5-gallon batch. That is about 10% more than the label intends. Misreading per total as per water does the reverse and mixes about 9% under strength. Where the label sets a minimum or maximum use-solution concentration, either error can take the mix outside the label.
The reverse check works as well. A label that reads "1:10 parts per water" is the same mix as "1:11 parts per total." If a second source prints 1:11 for what looks like the same product, the two may agree and differ only in convention. Confirm that against the label before assuming it.
When a conversion is not possible from the ratio alone
Do not convert, and confirm with the label or the manufacturer, in these cases:
- The label prints only "1:N" with no wording defining the parts.
- The label gives a ratio for a ready-to-use product and a different one for a concentrate, and you cannot tell which line applies.
- The instruction is by weight ("oz per lb") or by a dispenser setting, not by volume.
- The product is a disinfectant or sanitizer. Use the registered label's dilution, contact time, surface, rinse requirement, water temperature, and water hardness limits. Those are the authority, not this table. For food-contact surfaces, the local Food Code adoption may differ in edition, so check which version your jurisdiction uses. Do not use this page to choose a concentration for disinfecting or sanitizing.
- Hazard communication questions, such as secondary container labeling, fall under OSHA's Hazard Communication Standard, 29 CFR 1910.1200. The SDS for the concentrate is the source for hazards and composition (Sections 2, 3, and 9).
Using the table with the calculators
The table gives the dose per gallon and the finished volume per gallon of concentrate. To scale it to a specific batch, size, or per-gallon dose, use the Dilution Ratio Calculator or the Per-Gallon Dose Calculator. Enter the ratio and convention from your label, and confirm the worked-out arithmetic against the formulas above.
For the full process of locating the convention statement on a label, see the site guide "How to Read a Cleaning Chemical Dilution Label."