Epoxy Casting Volume & Resin Hardener Mix Calculator
Calculate resin and hardener quantities from mold volume, product ratios and liquid densities.
Keep weight and volume ratios distinct, plan packs and unmixed surplus, then save a purchase worksheet in KRW.
A is resin; B is hardener. Defaults are a fictional weight-ratio example.
Check the actual product ratio basis and liquid density. Weight and volume ratios may differ; cured specific gravity is not liquid density.
Prepared quantities cover the whole project. Check the product TDS and SDS separately for safe single-batch quantities, pour depth and working conditions.
4. Mixing and purchase worksheet
Product data unverified · Quantities below use assumed inputs. Check the purchased product before measuring. Product name not recorded
Net mold fill
1 L
Extra preparation allowance
0 L
Prepared project volume
1 L
A resin
916.667 g
Component volume: not calculated without density data
B hardener
183.333 g
Component volume: not calculated without density data
Ratio basis: By weight A:B = 5:1
Total prepared mass: 1,100 g · Effective mixed density 1.1 g/mL
Display quantities are rounded; calculations and pack counts use full precision. Check scale resolution and the manufacturer’s ratio tolerance separately.
| Preparation scenario | Volume L | A resin g | B hardener g |
|---|---|---|---|
| Fill only, no allowance | 1 | 916.667 | 183.333 |
| Entered allowance 0% | 1 | 916.667 | 183.333 |
Purchase counts and unmixed surplus
A resin: 1 containers × 1,000 g
Ordered: 1,000 g
Unmixed pack surplus: 83.333 g
B hardener: 1 containers × 200 g
Ordered: 200 g
Unmixed pack surplus: 16.667 g
Total material cost from entered prices: Enter price
A required product price of 0 means not entered. Kit counts use the larger component requirement. Preparation allowance differs from pack-rounding surplus. Check shipping, stock and shrinkage separately.
| Group | Count | Gross L/mold | Excluded L/mold | Net L/mold | Subtotal L |
|---|---|---|---|---|---|
| 1 | 1 | 1 | 0 | 1 | 1 |
Epoxy casting mix and purchase worksheet Sources checked: 2026-10-02 Product: not recorded Product document revision: not recorded Product data unverified: assumed values; check before measuring cm / L / g / mL / g/mL / KRW Mold group 1: Rectangular width × depth × fill height 20 × 10 × 5 cm Count / gross per mold / excluded per mold / net per mold / subtotal: 1 / 1 / 0 / 1 / 1 L Net fill / extra allowance / prepared volume: 1 / 0 / 1 L Extra preparation allowance: 0% (×(1+p/100)) A resin:B hardener ratio: 5:1 (by weight) Liquid mixed density: 1.1 g/mL A resin / B hardener / total prepared mass: 916.666667 / 183.333333 / 1,100 g Component volume A / B: Missing data: not calculated Purchase mode: separate packs Pack size A / B: 1,000 / 200 g Entered pack price A / B: price not entered / price not entered Pack count A / B: 1 / 1 Ordered A / B: 1,000 / 200 g Unmixed pack surplus A / B: 83.333333 / 16.666667 g Total material cost from entered prices: price not entered Prepared quantities cover the whole project; they do not determine safe single-batch size, pour depth or cure time. Check the actual TDS, SDS and a small test. Shipping, stock, fillers, absorption and shrinkage require separate checks.
Sources checked: 2026-10-02 · Arithmetic from dimensions and product data; no cure-time, exotherm or application-suitability assessment.
Connect epoxy cavity volume to measuring and purchasing
A mold’s liquid capacity and the mass placed on a scale are different quantities.
A 1 L cavity does not automatically require 1 kg of resin: the mixture includes hardener, and the product’s liquid density matters.
This epoxy resin calculator links cavity volume, the specified mixing ratio and whole-pack purchases in three steps.
Use it for a countertop repair, decorative casting or several small molds that share one product and ratio.
Start with the actual resin and hardener combination and its technical data sheet, including component order and ratio basis.
The initial 1 L, 1.1 g/mL and 5:1 weight-ratio inputs are fictional teaching values, not a manufacturer preset.
The calculation model has no country-specific rules; material budgets use KRW in both languages.
Confirm product-specific A and B quantities
Compare the worksheet with the purchased product’s data before measuring, ordering a small quantity or testing.
The confirmation checkbox records the user’s review; it does not certify cure performance or application suitability.
Functions and scope
- Calculate rectangular or cylindrical cavities, or enter a verified gross volume, then subtract inserts and multiply mold counts.
- Keep weight ratios distinct from volume ratios, with mixed or component liquid-density methods for weight ratios.
- Compare fill-only quantities with an entered allowance while preserving the component ratio.
- Calculate separate component packs or paired kits, unmixed surplus and costs from entered quotes.
- Save a TXT worksheet with product details, revision, assumptions and missing-data states, or print it.
Keep molds using different products or ratios in separate calculations.
Pool molds only when the same resin system and ratio apply throughout.
Prices are your own quotes; the tool does not fetch average market prices or optimize across alternative pack combinations.
Inputs, units and reading product data
Cavity and excluded volume
Measure inside dimensions, not outside dimensions, and use the actual fill height.
Enter only the wood or insert volume inside that fill region, in L per mold.
Excluded volume larger than the cavity stops the calculation; check units and overlapping regions.
Ratio basis and order
A means resin and B means hardener here.
Check whether your document lists them in the opposite order, then choose weight for g or volume for mL.
You can enter parts such as 100:20 directly; they do not need to add up to 100.
Liquid densities
1 g/mL has the same numerical value as 1 kg/L or 1 g/cm³.
A weight ratio and liquid mixed density provide individual masses; component densities also provide individual volumes.
Volume-ratio masses require both liquid component densities.
Density 0 means missing data and leaves affected quantities pending.
Pack contents and prices
Multiply kg by 1,000 to enter g, and L by 1,000 to enter mL.
For a kit, enter each container separately rather than placing total kit content in the A field.
A required product with price 0 leaves its budget pending; zero required containers cost 0 KRW.
The tool accepts up to 20 groups, each with 1–1,000 identical molds.
Dimensions use two decimal places in cm; entered and excluded volumes use three in L; density uses four in g/mL.
The 10,000 L prepared-volume range is a software limit, not a safe mixing quantity or recommended project size.
Volume and mixing formulas
1. Net fill and preparation allowance
Rectangular volume L = width × depth × height ÷ 1,000.
Cylinder volume L = π × (diameter ÷ 2)² × height ÷ 1,000.
Subtract excluded volume per mold, multiply its count, then sum all groups as V.
Prepared volume Vp = V × (1 + p/100).
A 10% allowance multiplies the requirement by 1.1; it is not an inverse-yield correction.
2. Weight ratio a:b and mixed density
Total mass M = Vp × 1,000 × liquid mixed density ρmix g.
A = M × a/(a+b), B = M × b/(a+b).
Individual component volumes remain unavailable without separate density data.
Check that the mixed-density value describes liquid rather than cured material.
3. Weight ratio and component densities
Mass fractions fA = a/(a+b), fB = b/(a+b).
M = Vp × 1,000 ÷ (fA/ρA + fB/ρB).
A_g = M × fA, B_g = M × fB; A_mL = A_g/ρA, B_mL = B_g/ρB.
An arithmetic mean of component densities is not used as mixed density.
This method assumes component volumes add before mixing.
4. Volume ratio converted to masses
A_mL = Vp × 1,000 × a/(a+b).
B_mL = Vp × 1,000 × b/(a+b).
A_g = A_mL × ρA, B_g = B_mL × ρB; total mass is their sum.
Different densities produce different mass proportions, so a volume ratio is never copied directly into a weight split.
Step-by-step use
- Check product data.
Record the resin/hardener combination and revision, component order, and by weight or by volume basis. - Measure the fill region.
Use inside dimensions and actual fill height, subtracting only inserts inside that region. - Select density data.
Use mixed or component densities for a weight ratio, and component densities for a volume ratio; avoid cured-property values. - Choose extra preparation.
Consider verified cup residue and test quantities without changing the hardener proportion. - Enter contents and quotes.
Use each container’s g or mL content, with separate prices or a kit price. - Save and review.
Compare the worksheet with the product data, decide on a small order and test, and confirm the actual working conditions.
Changing an input hides the old result until you calculate again.
Resolve missing-data messages before using affected quantities.
Direct volume entry supports a verified capacity for irregular shapes; it does not determine a measurement procedure or whether a mold may be exposed to water.
Worked examples: the same 1 L with different ratio bases
All densities, ratios and prices below are fictional verification inputs.
A 20×10×5 cm rectangular cavity with no excluded volume and one mold gives 1 L net fill.
The same fill volume can require different component masses when the ratio basis or density method changes.
| Conditions | A resin g | B hardener g | Total g |
|---|---|---|---|
| Weight 5:1, mixed density 1.1, allowance 0% | 916.667 | 183.333 | 1,100 |
| Weight 5:1, mixed density 1.1, allowance 10% | 1,008.333 | 201.667 | 1,210 |
| Volume 2:1, A density 1.2 / B density 1.0 | 800 | 333.333 | 1,133.333 |
| Weight 2:1, A density 1.2 / B density 1.0 | 750 | 375 | 1,125 |
Check volumes to see the distinction
The 2:1 volume example gives A 666.667 mL and B 333.333 mL.
The 2:1 weight example with the same component densities gives A 625 mL and B 375 mL.
Both sum to 1,000 mL, but mass distribution differs.
Calculations retain full precision; rounded display values may not sum exactly at the displayed precision.
Pack counts, kits, costs and surplus
Round separate component packs individually
Divide each requirement by its pack content in the same unit and round up.
The basic weight example needs one 1,000 g A container and one 200 g B container.
Fictional quotes of 30,000 KRW and 6,000 KRW total 36,000 KRW.
With 10% allowance, requirements become 1,008.333 g and 201.667 g, requiring two of each for 72,000 KRW.
Unmixed pack surplus is A 991.667 g and B 198.333 g, distinct from the allowance prepared for use.
Size paired-kit purchases by the limiting component
Kit count = max(ceil(A requirement/A container), ceil(B requirement/B container)).
The basic weight example needs two kits containing A 500 g+B 100 g; a fictional 30,000 KRW kit price gives 60,000 KRW.
The volume-ratio example needs one A 750 mL pack and one B 500 mL pack; fictional quotes of 20,000 KRW and 8,000 KRW total 28,000 KRW.
Verify compatible components and net contents; do not mix all leftover material if that would change the ratio.
Surplus is the unmixed component content ordered beyond the planned measuring quantities.
It does not indicate storage life for an already mixed resin batch.
A missing required price keeps the total budget pending rather than showing zero; shipping, additional taxes, existing stock and filler costs need separate checks.
Scale resolution and manufacturer ratio tolerance are independent of the screen’s decimal display.
Three practical scenarios
Countertop gap repair
Subtract wood only within the fill region.
For irregular boundaries, enter a verified gross volume and check leakage and absorption separately.
Multiple small castings
Group identical molds by count and add rows for different dimensions.
Pooling before pack rounding avoids buying a rounded number of bottles separately for every mold.
Review before ordering
Ask the supplier about product pairing, ratio units and individual container contents.
Compare the saved worksheet with the technical data; ordering, contacting the supplier and completing a test remain separate user actions.
Errors, assumptions and cautions
Review working conditions alongside quantities
These formulas do not predict exotherm, cure time, a safe single-batch size or layer conditions.
Use the product TDS or Application Guide for volume, depth and temperature, and its SDS for protection, ventilation and exposure instructions.
Do not interpret the entire prepared quantity as approval to mix it all at once.
- Distinguish cured specific gravity from liquid density; confirm product pairing, market and revision even within one brand.
- Do not subtract overlapping insert regions or portions outside the fill height twice.
- Mixing contraction, cure shrinkage, bubbles, absorption, pigments and fillers are not automatically corrected.
- Check the additive-volume assumption; when documented liquid mixed density is available, review that product-specific data first.
If excluded volume equals cavity volume, required material and pack counts are zero.
Do not change units or invent missing product values to bypass an error.
A missing-data message asks for verified inputs; it does not automatically repair an incorrect ratio.
Frequently asked questions
Are 2:1 by weight and 2:1 by volume equivalent?
A weight ratio compares masses; a volume ratio compares liquid quantities.
When component densities differ, the same numerical ratio cannot be transferred between the two bases.
Check the product label for by weight or by volume first.
Can I use water density when resin density is unknown?
Do not substitute water density for your resin.
Density 0 means missing data: cavity volume remains available while affected component quantities are held pending.
Ask the manufacturer for liquid mixed density or both liquid component densities.
Can I enter any specific gravity from the data sheet?
Check whether it describes an unmixed liquid, liquid mixture or cured solid.
Specific gravity in a cured-properties table is not automatically suitable for liquid fill calculations.
A value in kg/L has the same numerical value in g/mL; g/cm³ is also equivalent to g/mL.
Can extra hardener speed up curing?
Do not change the specified ratio to adjust cure time.
Preparation allowance scales both components together and preserves the ratio.
Check the actual product’s working time and temperature requirements separately.
Why are mL pack counts unavailable with mixed density?
Mixed density and a weight ratio do not determine individual component volumes.
Select the component-density method and enter both densities, or use verified pack content in g.
Multiply kg by 1,000 to enter g, and L by 1,000 to enter mL.
What if kit container sizes do not match the mixing ratio?
The kit count is the larger of the two rounded component requirements.
One component may have substantial surplus; verify both container contents and the correct product pairing.
The tool does not determine a future recipe or the reuse period for leftover components.
Does 10% allowance compensate for a 10% loss of supplied material?
Allowance adds to the required quantity, so 10% multiplies it by 1.1.
It is different from a yield model that divides by 0.9 when 10% of the supplied material is lost.
Choose an extra quantity based on verified cup residue, absorption and testing requirements.
Can I mix and pour the entire prepared quantity at once?
Prepared quantity is a whole-project purchasing and measuring plan, not a safe single-batch limit.
Check the product’s pour depth, volume, temperature, working time, layer conditions and SDS first.
Price 0 means not entered; shipping, existing stock and fillers need separate checks.
Primary sources and data review
Sources checked: 2026-10-02.
The October 2014 WEST SYSTEM technical data lists 105/205 at 5:1 by volume and 5.19:1 by weight, and 105/207 at 3:1 by volume and 3.64:1 by weight.
Its 1.18 and 1.15 specific-gravity values describe cured properties and are not used as liquid-density defaults here.
General instructions and market-specific or revised sheets may differ; check the latest TDS for the product actually purchased.
WEST SYSTEM’s mixing instructions advise preserving the specified ratio rather than changing it to alter cure time, with a small initial test.
EcoPoxy directs users to product-specific guidance for casting quantities, thickness and working conditions.
The calculator does not impose a universal product ratio, statutory rate or application-safety limit.
Prepare the product data and mixing worksheet together
Enter measured cavity dimensions and the intended product’s ratio and liquid-density data.
Separate component quantities, preparation allowance and pack surplus to review container counts and quoted costs clearly.
Save the result, compare it with supplier documentation, and confirm a small order, test and actual working conditions.
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