Resin Coaster Calculator
Enter the size and depth of your coaster mold and how many coasters you are making. You get the total mixed resin, the amount per coaster, and the resin and hardener to measure.
You need
– fl oz
– ml in total
- Per coaster: –
- Resin (Part A): –
- Hardener (Part B): –
Next steps
Split another amount into resin and hardenerCalculate a tray or other moldResin for common coaster sizesHow to use this calculator
- Pick round or square. For hexagon molds, enter the width across as a round diameter for a close estimate.
- Enter the inside size of one coaster and how deep you will pour.
- Enter how many coasters you are making and the ratio on your resin.
- Mix the total once, then pour each coaster. Small separate batches waste more resin.
Resin for common coaster sizes
Mixed resin for one coaster, without extra for waste:
| Coaster | fl oz | ml |
|---|---|---|
| 3.5 in round, 1/4 in deep | 1.33 | 39 |
| 4 in round, 1/4 in deep | 1.74 | 51 |
| 4 in round, 3/8 in deep | 2.61 | 77 |
| 4 in square, 1/4 in deep | 2.22 | 66 |
| 4.5 in hexagon (≈4.5 in round), 1/4 in deep | 2.2 | 65 |
Tips for better coasters
- Coaster molds are usually 1/4 to 3/8 inch deep. Fill to just below the rim for a clean edge.
- Work in a warm room (about 75 °F / 24 °C) so bubbles rise and pop more easily.
- Mix one batch for the whole set so every coaster has the same color.
- Let coasters cure fully, often 72 hours, before using them under hot mugs.
Frequently asked questions
How much resin do I need for a coaster?
A 4 inch round coaster that is 1/4 inch deep needs about 1.7 fl oz (51 ml) of mixed resin. A 4 inch square coaster at the same depth needs about 2.2 fl oz.
How much resin do I need for 4 coasters?
About 7.7 fl oz of mixed resin for four 4 inch round coasters, 1/4 inch deep, including 10% extra for what stays in the cup.
How many coasters can I make with a 16 oz resin kit?
About 8 coasters of 4 inch round and 1/4 inch deep, allowing 10% for waste. A 16 oz kit means 16 fl oz of resin and hardener combined.
How do I measure the depth of a coaster mold?
Fill the mold with water to the height you want, then measure the water with a ruler, or pour the water into a measuring cup to read the volume directly.
Should I pour coasters in one layer or two?
One layer is fine for clear or colored coasters. If you embed dried flowers or photos, pour a thin first layer, place the items, let it gel, then pour the rest so the items stay put.