The EASY Way to Calculate How Much Resin Do I Need?

How much resin do I needSo I’m guessing you googled, ‘How much resin do I need?’ and ended up here. Kudos for thinking about that now instead of when you’re halfway through your project. Mixing way too much or not nearly enough epoxy resin is frustrating.

But so is math.

I’ve got three options for you, from easiest to hardest, to answer the question of how much resin do I need.

Option 1: Use water

Difficulty level:  Easy

If you’re working with something with ‘sides,’ (like a mold or bezel), fill it with water. Then, pour the water into a measuring spoon or cup.

*1 teaspoon equals 5 mL

*1 ounce equals 30 mL

Know that you won’t catch every drop of water. Mix a little more resin to account for this.

Option 2: Resin Calculator

Difficulty level: Easy to intermediate

Measure the length, width, and height of your item or flat surface.

Put them into this calculator. (Yes, it really is that easy to answer how much resin do I need)

If you’re coating a surface, use 0.07 inches as the height. (That’s the level that resin for art settles to.)



⭐️ BONUS:  Learn more about calculating the amount of resin to cover a painting.

Option 3:  Do the math yourself

Difficulty level: Hard to Insane

For you crazy people that busted curves throughout high school and college, this is for you.

Although, you probably already knew this was your answer for how much resin do I need.

And for us mere mortals, you can skip this part. Or maybe join the Resin Obsession email list so you can stay in the know about resin and all the cool resin supplies we sell.

Let’s say a mold cavity is 1 inch square by 1/2 inch deep.

1 inch x 1 inch x 1/2 inch equals 0.5 cubic inches. Since 1 cubic inch equals 16.3871 milliliters, this mold cavity holds 8.189355 ml (the math is 16.3871 x .5). I would just round up to 9 ml from here. Or round up to 10 ml to make it even easier.

What do you do if you are casting into a cylinder or sphere?

Cylinder volume equals Pi (3.14) x radius2 x height. Sphere volume equals 4/3 x Pi (3.14) x radius3

Note: Radius is the distance halfway across. Diameter is the distance all the way across. To get the radius, you will need to divide the diameter by 2. Don’t even ask me where that Pi number came from.

Don’t forget, if you’re only using half of a sphere mold, divide your volume by two.

What if your center is hollow?

Let’s do the math with this bangle bracelet mold.

resin bangle mold 414









The dimensions are 2 5/8 inches inner diameter, 5/8 inches wide, 3/4 inches tall.

The volume of the ‘outer’ circle: 2 5/8 inches plus 5/8 inches times two (two because of each side), which equals 3 7/8 inches total diameter. Using the formula above, the volume of a cylinder that size equals:

3.14 x (3.875/2)2x .75 which equals 8.84 cubic inches.

Like this post? You may be interested in  The Simple Steps To Casting Resin In Silicone Molds

But hold on, we need to subtract the inner cylinder. Otherwise, it’s like we’re filling up the entire bracelet without a hole for your wrist.

Inner cylinder volume equals:

3.14 x (2.625/2)2x .75 which equals 4.057 cubic inches.

That means the volume of the bangle is 8.84 cubic inches minus 4.057 cubic inches, which equals 4.783 cubic inches. Since 4.783 cubic inches equals 78.38 milliliters (4.783 x 16.3871), divide that number by 30, and you get approximately 2.6 ounces.

Or you can use the free resin calculator.

Really. It’s free. Save your brainpower for your resin crafts.

There are a few other things you need to know if you are asking how much resin do I need:

1.  After you’ve figured out how much resin do I need, make sure that you are mixing between the recommended minimum and maximum mixing amounts. If you don’t mix the minimum, your resin won’t cure. If you mix more than the maximum, it will overheat and smoke.

⭐️ BONUS: We’ve got those mixing amount numbers for you in our resin buying guide.

2.  Always err on the side of mixing a little more rather than a little less. If you have some extra resin, have some leftover resin projects ready to go.

3.  Now that you’ve done the math, measure your parts A and B accurately. Use mixing cups with graduated lines to make sure your amounts are correct.

Want to learn about epoxy from the comfort of home?

Buy a copy of Resin Fundamentals.  I wrote the ebook with the beginning artist in mind to get you expert-level status in only a couple of hours. Buy the PDF book now and you’ll get a download link to your emailin minutes.


Unpublished Blog Posts of Resin Obsession, LLC © 2023 Resin Obsession, LLC

63 thoughts on “The EASY Way to Calculate How Much Resin Do I Need?

  1. I was pouring a layer of clear cast 7050 over painted woof frames. I did give the hsrdener and resin a warm bath for about 5 minutes after coating the third one, it got like hard taffy and smoke actually stsrted to come from it. Did I give it too long of a bsth? Any help is much appreciated.

    1. Using inches then converting to ml (wrongly referred to as mL) is just ridiculous. Stick to metric and you’ll be just fine. Over complicating things with measurements in imperial because Americans refuse to use metric, even though they are taught it in school is lame.

      1. We use the imperial system, so inches and ounces are what we are comfortable using, for almost everything. It isn’t our fault Britain took her citizen’s guns and rights, and we had to completely start over on a new continent! Since we are the powerhouse of the world, why should we use the metric system. Hasn’t quite worked out for the rest of you, has it?

  2. When measuring out resin and hardener I read that the cough syrup measuring cups are the best to use. Can they be reused? I literally threw away a stack of them several months ago… until I caught the “Resin jewelry bug”! I’m sure the answer is somewhere, but I have read and watched so many tutorials lately I’ve probably missed it! Thanks

  3. Hi how much resin should I mix i f I need to create a big canvas (like your videos) , the measure is 1 milliliter of resin vs 1cc of area?. thanks a lot.

  4. all i need to know is how many ounces of resin / hardener do i use to do 2by2 sqare feet canvas? simple lamen terms please not math mumbo jumbo i just do not get it…

  5. I’m looking to make a diorama using a 36″ model submarine. I will be cutting the hull off below the water line so I’ll be needing approximately 42″ length by 7″ width and a depth of around 1-1.5″. I don’t want to buy way more than I need (and don’t want to run out part way through). What sort of weight would I need for this? (I’ve never used resin before). Thanks.

  6. there’s a great calculator at artresin/calculator, you just input your numbers and it tells you how much you need.

  7. Question: I’m pouring a clear ball but half comes out clear and the other half is really messed up and needs intense filing can I pour in layers and cure it to keep from getting this problem.

  8. How much resin and hardner will be use for 14ft length and 14ft breadth..after conversion to meters it’s 16sqms

    1. How deep do you want your casting? There is a calculator in the article that can do the math, but you need to know how deep you want to pour the resin.

  9. I’m about to take on my first river table. I’ve found lots of great info for calculating resin amounts but all pertain to a regular or at least semi-regular shape. Is there any way (beyond guessing) to calculate a very irregular shape?

  10. I tried using the measurement system, but didn’t understand the number that came up. It just seemed to be too much. I’m trying to make an 8×10 resin pour in a frame for my shell collection. I think an 1/8 on would be thick enough. What do you suggest?

  11. I’m doing a round table top that has a diameter (measured all the way across, right?) of 42″. How much resin do I need?!

  12. I am doing very small pieces where it’s a laser cut hole in a piece of 1/8 plywood. I have figured out the approximate area and then figured out how many per cubic inch. Next I need to figure out how many I can do before the resin stops being workable and then will do the math on how much to mix at a time. A very reverse way than most but it should work for my intended use.

  13. I’m wanting to do a floor the room is 14ft by18ft how hard would this be as I am putting down plywood and pre painting it or would I need to do each individual sheet than lay down

  14. This will be my first project and im so excited. How much resin will i need to cover 4- 4×4 ceramic tiles.
    Thank you for all your information and videos.

  15. Hello I am making a table and measure that I needed approximately 1096 oz but now how do I determine how much Resin (part A) and harder (part B) I pour?

    1. Hi Kim, your resin kit directions should tell you how to mix your resin, either by weight or by volume. For example, if the directions say to mix 1 to 1 by volume, then you will need 548 ounces of each part.

  16. I’m not sure how to use the calculator for my project. I’m doing alphabet keychains and they’re all different sizes and shapes so rectangle/square and cylinder don’t work for me. The only thing that’s consistent is the mold is 1.57in. Height. Also, my letters keep coming out curved down like it shrunk when curing. Is there a way to fix this while pouring or would the easiest way be to just add more resin on them after they’ve cured???

    1. Hi Jamie, unfortunately, trying to figure out exactly how much resin you need for the letter molds is a little tedious using the calculator. You may want to try filling a few cavities with water, then measuring the water. Average it out across the number of cavities you poured into and that will give you an idea of how much resin you need for each letter.

      As for the edge, what you are experiencing is normal. You can either sand the edges down or fill with a doming resin after during. You can buy doming resin in our store here:

  17. I use the water measure system quite often, but I do it this way.
    I take let’s see a 16oz measuring cup full with water, pour what I need over the item in question , look how much water is left in the cup and what you used is what you need in resin. I hope I made it clear enough

  18. One more conversion for us dummy Americans. Most of the people that I associate with use THE good old imperial system. 1 cubic inch = 0.55413 ounces.

  19. Hi

    Looking to cover a table top that I’ve covered with bottle tops, I’ve used the calculator and it’s saying I need 8835.73 ml of resin. Measurements are 75cm diameter 2cm depth, but surely this will be way too much when you take into account the volume that all the bottle tops will use. Would I be right thinking that half of this amount will still be more than enough?


    1. Hi Chris, the resin is going to leak underneath the bottle caps. i.e., you are going to need enough to fill the bottle caps with resin too. You can start with trying about a third of the amount, then seeing if you need to add more. The thin layer will also help you get out bubbles easier.

  20. Hello, I’m looking to make some rolling trays. What is a good resin to use? Does it need to be food safe? Thank you

  21. Hey there… I am still confused to know how will I know the exact amount of hardner and resin I should mix… according to my mold…
    Yesterday I used a resin calculator app didn’t worked so well…
    I putted my first layer and kept half of it for the second round….but after some time my left over resin was cured on the mug only😂…… And the resin I putted on the mold is still to be cured… what should I do and how should I know the exact amount of hardner and resin to use and mix… please help…I used high gloss resin for preserving my rose….

  22. If the measurements calls for 1 ounce per square foot. Is that one ounce of epoxy and one once of hardener or is it a half an ounce of both to equal one ounce?

    1. Hi Jamie, it’s 1 ounce total. You’ll need to check your kit’s directions to see how much of each part to mix together. (not all resins mix 1:1)

  23. Hi I put a golf ball in a cube mold and poured it in 2 layers, the 1st layer was perfect the 2nd wasn’t it is cloudy and has a seam line right in the middle, I’m wanting to know if it can be sanded and polished out or can I cut the ball out and start again and if it can be removed can you explain how to. Any advice/help greatly appreciated. Thanks in advance

    1. Hi Joanne, I’m afraid you won’t be able to sand away the seam line. You can try cutting the ball out of the cured resin with power tools, then recasting.

  24. Thanks for your help. so it looks like back to square one, that is once I get the ball out fun times ahead

  25. Love all the information, and appreciate the time you have clearly put into all of this!! Thank you!! I did have a tiny suggestion in regards to the first option listed…. And I could be wrong and need to be corrected But… When I am trying to figure out how much resin I need, I use a bag of dry rice, and just pour the rice in my mold, then pour that into my cup that I’m going to mix in. I’ve always been afraid of having water in my molds right before I use them. I also have a notebook that I keep in my work area and have pages dedicated to each of my molds (ideas/things I’ve learn after using each of them/etc.) And I always write down how much rice I ended up measuring so then I don’t have to do it the next time I use that mold, and don’t have to “remember how much” because I know that’s just lying to myself LOL!

    1. I love a good journal too Breann. Sometimes I can’t even remember what I ate for breakfast. LOL

  26. I am with Breann and Katherine. The first thing I do when I get a new mold is to measure its volume. Being a scientist at heart (that would be ‘nerd’ to the non-scientific community) I created a spreadsheet* to calculate the volumes of all sorts of geometric shapes. Many molds can be broken down into combinations of geometric shapes, but for those that can’t – like a figurine of something (chess pieces for instance) I just use the water method. When I add large or significant inclusions into a casting I calculate their volumes as well – usually by putting them into a known volume of water and noting the change in the water level in my graduated cylinder or measuring cup/bowl. If the object(s) tend to float then I just hold them underwater with a couple of toothpicks long enough to read the volume change. I have a ‘log’ – a WORD document/table – that has a picture of each mold and the inclusions along with their relevant dimensions and volumes. * The spreadsheet is flexible in that I just tell it what units I am measuring something in and indicate what units I want the volume in, and it does all the calculations for me. Anyone care to know how many ml are in a cubic furlong? FYI – there are copious programs and apps to convert just about any unit of measurement into some other unit of measurement.

  27. Hi I want to make a round resin sea view wall clock of 40cm width X 40cm lenght X 2cm thickness. How much resin will I need please. Reading up I came to an answer of 1.8 litres. Is this correct? Also would 2cm thickness be enough, I will pour onto a wood piece. Thank you

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