To convert resin ounces to ml, multiply the number of US fluid ounces by 29.5735. For example, 8 US fluid ounces equals about 236.6 milliliters (mL), but check whether your resin kit lists fluid ounces or ounces by weight before mixing.
This difference matters because fluid ounces measure volume, while ounces by weight measure mass. They are not interchangeable, and using the wrong conversion can leave a resin kit with the wrong amount of resin or hardener.
How to convert resin ounces to milliliters
Milliliters measure volume, the amount of space a liquid takes up. US fluid ounces also measure volume, so you can convert between them using a fixed conversion factor.
Use this formula:
Milliliters = US fluid ounces x 29.5735
For an example amount of 4 US fl oz, the calculation is:
4 x 29.5735 = 118.294 mL, which rounds to 118.3 mL.
The reverse conversion works by dividing milliliters by 29.5735. For example, 250 mL ÷ 29.5735 = about 8.45 US fl oz.
These conversions use US fluid ounces. Imperial fluid ounces, used in the UK measurement system, have a different size. If your kit uses imperial units, confirm the unit before applying this chart.
Resin ounces to ml conversion chart
Use this chart to convert common example quantities from US fluid ounces to milliliters. The values are rounded to one decimal place, so small differences may appear if you calculate with fewer decimal places.
| US fluid ounces (fl oz) | Milliliters (mL) | Approximate liters (L) |
|---|---|---|
| 1 fl oz | 29.6 mL | 0.030 L |
| 2 fl oz | 59.1 mL | 0.059 L |
| 4 fl oz | 118.3 mL | 0.118 L |
| 6 fl oz | 177.4 mL | 0.177 L |
| 8 fl oz | 236.6 mL | 0.237 L |
| 10 fl oz | 295.7 mL | 0.296 L |
| 12 fl oz | 354.9 mL | 0.355 L |
| 16 fl oz | 473.2 mL | 0.473 L |
| 24 fl oz | 709.8 mL | 0.710 L |
| 32 fl oz | 946.4 mL | 0.946 L |
To convert milliliters to liters, divide by 1,000. For example, 500 mL equals 0.5 L. This is useful when a kit lists its total volume in liters but your measuring cup uses milliliters.
How to read a resin kit's mixing ratio
A mixing ratio tells you how much resin to combine with how much hardener. The ratio may be given by volume or by weight, and the distinction affects how you measure each part.
An example kit labeled with a 2:1 ratio by volume calls for two equal volume units of resin for every one volume unit of hardener. If the example resin amount is 100 mL, the matching hardener amount is 50 mL, making 150 mL total before mixing effects.
A ratio by weight works differently. It compares the mass of each component, so measuring the same ratio with a volume cup may give the wrong result. Use the measurement method specified by the kit maker.
Converting ounces to milliliters does not tell you the correct mixing ratio. It only converts a volume measurement. Check the kit label or instructions to find the required ratio and whether it is measured by volume or weight.
How to use a mix ratio calculator
A mix ratio calculator can help work out the amounts of resin and hardener after you know the kit's stated ratio. It does not replace the kit instructions, and its result is only useful when you enter the correct ratio and measurement method.
- Find the mixing ratio printed on the kit instructions.
- Confirm whether the ratio is by volume or by weight.
- Enter the ratio as written by the maker.
- Enter the amount of resin you plan to measure, using the unit the calculator accepts.
- Read the calculated hardener amount and check its unit before measuring.
If you have only an amount in US fluid ounces, convert that volume to milliliters first when needed. Do not use a volume conversion to replace a weight-based measurement.
Worked example: converting a resin kit amount
Suppose an example project calls for 12 US fl oz of mixed liquid by volume. To convert that amount to milliliters, multiply 12 by 29.5735.
12 x 29.5735 = 354.882 mL.
Rounded to one decimal place, the example total is 354.9 mL, or about 0.355 L. This is the converted volume, not a recommendation for a particular project or kit.
Now suppose an example kit uses a 2:1 ratio by volume and you want to prepare that total amount. The ratio has three parts altogether: two parts resin and one part hardener.
Divide the total volume by three: 354.9 mL ÷ 3 = 118.3 mL per part, using the rounded total.
Calculate the resin amount: 2 x 118.3 mL = 236.6 mL.
The hardener amount is one part, or 118.3 mL. Together, the rounded amounts give 236.6 mL + 118.3 mL = 354.9 mL.
Keep in mind that this example applies only to a ratio stated by volume. If a kit gives its ratio by weight, calculate the component masses instead and use the maker's specified measurement method.
Common conversion mistakes and their costs
The first mistake is treating ounces by weight as fluid ounces. For example, 8 oz by weight means a mass of about 226.8 g, while 8 US fl oz means a volume of about 236.6 mL. These figures describe different properties, so you cannot swap one for the other without additional information about the liquid.
The second mistake is using the wrong fluid-ounce system. Eight US fl oz converts to about 236.6 mL. Eight Imperial fl oz converts to about 227.3 mL. The difference is about 9.3 mL, which can affect a measured batch.
A third mistake is rounding too early. If you convert each small component separately and round each result, the final total may differ slightly from a calculation using full precision. Keep extra decimal places during the calculation and round the final measurement to a level your measuring tool can support.
Another mistake is using the correct conversion with the wrong mixing ratio. A perfect conversion cannot fix an incorrect resin-to-hardener proportion. Follow the maker's instructions and safety data sheet for mixing and handling.
When the conversion method is not enough
The fluid-ounce conversion is reliable when the starting unit is a US fluid ounce and the target is milliliters. It cannot identify whether a label means fluid ounces or ounces by weight, so the unit description matters.
It also cannot tell you whether a resin kit's ratio is by volume or weight, how much material a surface needs, or whether a product is suitable for a planned pour. Those details come from the kit instructions and the measurements for your project.
For a weight-based ratio, you need the component masses or the correct weighing instructions. Do not infer a resin's mass from its volume unless you have a reliable density value for that specific material.
Frequently asked questions
How many milliliters are in 1 US fluid ounce of resin?
One US fluid ounce equals about 29.6 mL. This is a volume conversion and applies regardless of the liquid's brand, although the same volume can have a different mass for different liquids.
Is 1 ounce of resin the same as 30 mL?
It is a useful rounded estimate if the ounce means a US fluid ounce. The more precise conversion is about 29.5735 mL, so 30 mL is slightly higher.
Can I measure resin and hardener in milliliters?
Yes, when the kit specifies a mixing ratio by volume. If the ratio is by weight, use the maker's required weighing method instead of measuring both components by volume.