1Measure the usable inside cavity
Use inside dimensions or the finished-candle dimensions for cylinder, tapered round/cone, square/rectangle or full-sphere molds. The calculator works in centimetres or inches.
3D Candle Mold Wax Calculator
Mold capacity planning
Estimate wax for regular candle molds from inside dimensions
Choose the closest supported mold shape, enter the usable inside measurements, and turn the calculated cavity volume into a practical wax estimate using a clearly labelled planning density or your exact wax density.
2Choose the density basis
Use the presets as broad planning factors, or enter the density supplied or tested for your exact wax. Then plan one cavity or a batch of identical cavities.
Detailed or sculptural mold? Geometry is best for regular shapes. Once you own an irregular body, flower, animal or novelty mold, measuring its real cavity with the Water-to-Wax Volume Converter is usually the better method.
Mold-to-wax planning tool
Turn mold dimensions into a practical pour plan.
Use the usable inside dimensions of a regular mold to calculate cavity volume and estimate the wax needed for one cavity or a batch.
- 1Choose the mold
- 2Add measurements
- 3Prepare the pour
Cylinder cutawayEstimate · not to scale331 g
Your visual pour plan
Prepare this batch
Weigh 331 g of wax.
10 cm high · 7 cm diameter · 1 cavity · no extra allowance
Enter valid mold measurements to see your estimate.
Batch composition100% wax
Wax base331 g
Fragrance oil0 g
Cavity volume / cavity384.8 mL
Estimated wax-only / cavity331 g
Extra included0 g
How to calculate wax for a regular candle mold
The calculator first finds the ideal inside cavity volume. Because 1 cm³ equals 1 mL, that volume can then be converted into a practical wax estimate using the density basis you choose.
Calculate the inside cavity volume
Choose the closest supported regular shape and enter the usable inside measurements.
Use the dimensions of the wax cavity or finished candle, not the outside silicone walls. The formulas below calculate the ideal volume of the geometry represented by those measurements.
Cylinderπ × radius² × usable height
Square / rectanglewidth × length × usable height
Full sphere4 ÷ 3 × π × radius³
Tapered round / coneπ × height ÷ 3 × (r₁² + r₁r₂ + r₂²)
- 1Choose the closest regular shape
Use cylinder, tapered round/cone, square/rectangle or full sphere. The tapered mode is circular, not a tapered square or rectangular mold.
- 2Measure the usable inside dimensions
For a rectangle, enter both width and length. For a true pointed round cone, bottom diameter can be 0. Sphere mode assumes a full sphere cavity.
- 3Use the fill height you will actually pour
If the mold is not filled to its rim, enter the usable height rather than the full outside mold height.
Convert cavity volume into a wax plan
Volume is mathematical; wax weight depends on the density value used for your material.
Wax-only estimatecavity volume × wax density
Batch estimateone-cavity amount × identical cavity quantity
Extra allowancebase batch × (1 + allowance %)
If fragrance is enteredfragrance = wax × fragrance-load %
Preset densities are broad planning factors. When your supplier provides a density for the exact wax—or you have a reliable tested value—use that instead. Fragrance load is treated as a percentage of wax weight for batch planning and does not predict the exact finished blend volume.
Worked example: 7 cm diameter × 10 cm cylinder
Cavity volume384.8 mL
Planning density0.86 g/mL
Wax-only estimate331.0 g
With 5% extra347.5 g total
The 331.0 g value is a planning wax estimate based on the selected density—not a guarantee that every real 7 × 10 cm mold will take exactly that amount.
Density rule: supplier or tested data for your exact wax is stronger than a generic preset. Record the actual amount used after a successful pour if you want a repeat-production reference for that mold and wax combination.
Know when geometry is not the best method
Detailed sculptural molds often need a measured capacity rather than a simplified geometric approximation.
Body, flower, animal, bubble and novelty molds may contain curves, recesses and varying cross-sections that a cylinder, sphere or rectangular formula cannot represent well. After you receive the mold, measuring the actual cavity is usually the stronger method.
For irregular molds: use the Water-to-Wax Volume Converter. The geometry in this calculator is mathematically exact for the ideal shape entered, but the real mold can still differ because seller measurements may be rounded or external and wax density varies by formulation.
3D candle mold wax calculator FAQs
Answers about inside measurements, rectangular and cone molds, wax density, irregular cavities, fragrance, batch quantities and estimate accuracy.
How do I calculate how much wax I need for a candle mold?
For a regular mold, measure the usable inside cavity and choose the closest supported shape. The calculator finds its ideal volume and multiplies that by the selected wax-density value. For irregular sculptural molds, a measured cavity is usually more useful than simple geometry.
Should I measure the inside or outside of a silicone candle mold?
Use the usable inside cavity or the dimensions of the finished candle, not the outside silicone walls. Outside dimensions include the mold material and can overstate the space available for wax.
Can I calculate a rectangular candle mold?
Yes. Choose Square / rectangle, then enter usable fill height, inside width and inside length. For a square, enter the same value for width and length.
Can I calculate a cone-shaped candle mold?
Yes. Choose Tapered round / cone, enter the top diameter and usable fill height, and enter 0 for the bottom diameter when the circular mold comes to a true point. This mode is not for a tapered square or rectangular cavity.
How accurate is the 3D Candle Mold Wax Calculator?
The shape formula is mathematically accurate for the ideal regular geometry represented by your inside measurements. The wax amount is still a planning estimate because real mold cavities, seller measurements and wax density can differ.
What wax density should I use?
Use the density supplied or tested for your exact wax when available. The wax presets in the calculator are planning values, not universal constants for every soy/plant, paraffin or beeswax formulation.
What should I use for an irregular body, flower or animal mold?
Use the Water-to-Wax Volume Converter after you have the mold. Measuring the real cavity is normally better than forcing a sculptural shape into a cylinder, sphere or other simple formula.
Does fragrance load change how much wax I should weigh?
If you enter fragrance load, the calculator treats it as a percentage of wax weight and splits the planned target mass into wax and fragrance oil. This is a batch-planning calculation; it does not predict the exact finished blend volume or override your wax and fragrance supplier limits.
What if my silicone mold has several identical cavities?
Calculate one cavity from its inside dimensions, then set Batch quantity to the number of identical cavities you plan to fill. If the cavities are different sizes, calculate each size separately rather than treating them as identical.
Why add extra allowance?
Extra allowance is optional. It can cover topping off, wax left in a pitcher or small pouring losses. Use an amount that matches your own process rather than assuming extra wax is always required.
Can I use inches instead of centimetres?
Yes. Switching between centimetres and inches changes the displayed measurement while preserving the same internal physical dimensions. You can also display wax results in grams or weight ounces without changing the calculated amount.
From mold capacity to a finished, tested candle
Measure irregular cavities, plan wax and fragrance, choose a wick starting point, estimate cooling and use real burn data as you move from mold dimensions to a finished candle.