Candle Burn Time Estimator

How It Works

Candle burn time is essentially a mass-flow problem: fuel divided by burn rate. Total hours ≈ net wax weight (g) / burn rate (g/h), where burn rate is set by wax family and wick size.

Published burn rates from Candle Science's wick guide (candlescience.com/wax/wick-guide) and Wooden Wick Co. data sheets give typical values:

• Beeswax — 4-5 g/h, the slowest common wax; dense crystalline structure limits how fast wax reaches the flame.
• Soy (GW-464) — 5-6 g/h, softer than beeswax so slightly faster.
• Coconut and coconut blends — 5-6 g/h, similar to soy.
• Paraffin — 6-7 g/h, fastest of the mainstream waxes.
• Beeswax/soy blends — interpolated by mass fraction.

Wick size matters more than most makers expect. A CD-16 in a 240 g soy candle burns at 4.5 g/h and lasts about 55 hours; the same candle with a CD-20 (one size larger) burns at 6.2 g/h and lasts only 39 hours. National Candle Association testing guides recommend matching wick size to container diameter within a narrow range — too small produces tunneling, too large produces sooting and fast burns.

Container geometry has a secondary effect. A tall narrow container concentrates the burn pool near the wick and burns slightly slower; a short wide container spreads the pool and evaporates more scent throw per hour, burning slightly faster. The tool uses container diameter as the primary geometry input, which captures the effect within about ±10%.

Fragrance load also contributes as fuel. Every 1% fragrance oil in the candle acts as roughly 1% additional fuel-by-mass, but fragrance burns hotter and less clean than wax, so a highly fragranced candle can burn 5-10% faster than the base wax number suggests. The tool applies a small correction for fragrance percentage above 6%.

How to Use This Calculator

1. Select your wax type — Soy, paraffin, beeswax, coconut, or a specific blend from the dropdown.
2. Enter the net wax weight — the wax weight only, in grams, not including the container or wick clip.
3. Choose the wick size — small, medium, or large matched to the recommended container-diameter range.
4. Enter the actual container diameter — to check wick-to-container match and apply the geometry correction.
5. Set fragrance percentage — 0-12% as used in your candle; the tool applies a small correction above 6%.
6. Read the estimated burn time and copy the label text — the tool produces a printable label string like "Approximate burn time: 55 hours".

Real-World Use Cases

Retail label estimate

A candle maker is printing labels for a 240 g soy container candle with a CD-16 wick. The tool reports about 55-60 hours based on GW-464 soy at ~5 g/h burn rate. She rounds down to 50 hours for the label (retail labeling convention is conservative) and moves on to the next SKU.

Comparing wax choices

A maker is choosing between GW-464 soy (5-6 g/h, softer) and Golden Wax 415 (4-5 g/h, harder pillar-style) for the same 200 ml container filled to 90% with 174 g of wax. GW-464 gives about 32-35 hours; Golden Wax 415 gives about 38-43 hours. The trade-off is that Golden Wax 415 needs a slightly larger wick to burn cleanly, which pulls burn rate back up. The tool shows both options side by side.

Diagnosing a fast burn

A customer reports their 8 oz (~226 g) soy candle finished in 25 hours instead of the labeled 50. The maker enters 226 g soy with the actual wick used and finds the CD-22 (rather than the CD-16 the label assumed) burns at 8-9 g/h, giving 25-28 hours — matching the customer report exactly. The fix for the next batch is to drop to a CD-16 or CD-18.

Tips & Safety Notes

• Test-burn 3-4 candles per batch before finalizing the label. Published burn rates are averages and real batches vary ±15%.
• A wick too small causes tunneling (a narrow well melts down the center, leaving side wax unburned) and effectively cuts usable burn time in half.
• A wick too large causes sooting, mushrooming, and faster burn. Look for a clean, straight flame and a full melt pool that reaches the container edge within 2 hours of first burn.
• Trim wicks to 6 mm before each lighting. Long wicks burn hotter and increase soot; short wicks stall out.
• First burn duration matters. Burn long enough on the first lighting to reach the container edge (typically 2-4 hours). Short first burns train the melt pool into a tunnel that persists for the rest of the candle's life.

Limitations & What This Tool Cannot Do

• Wick manufacturer data is baseline. Published burn rates assume the wick manufacturer's own tested wax family; substituting a different wax (e.g., using a paraffin-rated wick in soy) breaks the estimate. The tool covers common wick series (CD, ECO, HTP, LX, Wooden) with published data for common wax families.
• Container geometry not fully modeled. Uses container diameter as the primary geometry input; tall narrow containers and short wide containers with the same total volume can burn 10-15% differently. The tool captures the average behavior.
• No burn-quality signal. Predicts hours only, not whether the burn is clean (no tunneling, no sooting, no mushrooming). A wick that produces the right burn hours can still have quality problems that only a test burn reveals.

FAQ

How is candle burn time calculated?

Divide the net wax weight by the burn rate. Burn rate depends on wax family (beeswax 4-5 g/h, soy 5-6 g/h, paraffin 6-7 g/h) and wick size (larger wicks burn faster). A 200 g soy candle with a medium wick at 5 g/h burns about 40 hours.

Does the wick size change the burn time significantly?

Yes. Moving up one wick size in the CD series (say CD-16 to CD-20) typically increases burn rate by 30-40%, cutting burn time by roughly a third. Wick size has more impact on burn time than fragrance load or ambient conditions.

Why do soy and paraffin candles of the same weight burn for different lengths of time?

Paraffin has lower melting point and lower heat of vaporization than soy, so it wicks to the flame faster. A 200 g paraffin candle typically burns 5-10 hours shorter than a 200 g soy candle with the same wick, simply because paraffin evaporates faster at the same flame temperature.

What is a "burn rate" and how does it relate to wax hardness?

Burn rate is mass of wax consumed per hour, in g/h. Harder waxes (higher melting point, denser crystalline structure) burn slower because it takes more heat to melt the wax at the pool edge. Beeswax and hard pillar waxes are the slowest; softer container blends are faster.

How does container shape affect burn time?

Tall narrow containers concentrate the heat near the wick and produce slightly slower burn. Short wide containers spread the melt pool and expose more wax surface to evaporation, giving slightly faster burn. Same volume in a tall vs wide container can differ by 10-15% burn time.

Why is my candle burning much faster than the label estimate?

Three most common causes: wick is oversized for the container (biggest effect — check that wick matches container diameter), fragrance load is high and adds fuel (each 1% fragrance adds ~1% burn mass), or the candle sits in a draft that accelerates evaporation. Test-burn with the wick and fragrance from the customer complaint and compare to the label estimate.

Related Tools

• Candle Wax & Fragrance Calculator — Wax weight and safe fragrance load for the same candle
• Resin Exotherm Calculator — Same-lab estimation tool
• Varnish Dilution Calculator — Same-lab estimation tool

References

• Candle Science wick guide and burn-rate reference (candlescience.com/wax/wick-guide) — CD, ECO, HTP wick series and typical burn rates
• Wooden Wick Co. burn rate data — wooden wick burn characteristics
• National Candle Association candle-testing best practices — recommended burn-time labeling and test-burn methodology

Reviewed by the Craft Calc Lab team on August 1, 2026.