Calculator Inputs
Formula Used
Step 1: Convert wax amount to mass (grams). If you enter volume, wax mass = volume × density.
Step 2: Estimate a baseline burn rate from candle diameter:
base_rate(g/hr) = 3 + 0.08 × diameter(cm)²
Step 3: Apply adjustment factors for wax, wick, container, airflow, additives, and temperature:
adjusted_rate = base_rate × wax_factor × wick_factor × container_factor × airflow_factor × scent_factor × temp_factor
Step 4: Burn time (hours) = wax_mass ÷ adjusted_rate.
How to Use
- Choose weight for best accuracy, or volume if needed.
- Select wax type, wick size, and candle style to match yours.
- Enter candle diameter and estimated additives or scent load.
- Set outdoor conditions, especially airflow and temperature.
- Pick a typical session length, then press Calculate.
- Use sessions and hours to plan refills for garden lighting.
Example Data Table
| Wax (g) | Wax Type | Diameter (cm) | Wick | Style | Airflow | Adj. Rate (g/hr) | Burn Time (h) |
|---|---|---|---|---|---|---|---|
| 120 | Soy | 5.5 | Medium | Jar | Low | ~5.4 | ~22.2 |
| 200 | Paraffin | 7.0 | Large | Pillar | Medium | ~9.0 | ~22.2 |
| 300 | Beeswax | 8.0 | Medium | Jar | Low | ~7.3 | ~41.1 |
| 150 | Gel | 6.0 | Medium | Tin | High | ~7.0 | ~21.4 |
Examples are illustrative. Real burn time depends on wick tuning and wax blend.
Wax Quantity and Expected Runtime
Accurate burn planning starts with wax mass. A heavier candle contains more fuel, but the hourly use rate rises as diameter increases. If you only know volume, convert it to grams using density for the selected wax. This avoids underestimating long garden evenings. Record the net wax amount after additives, because fragrance displaces wax and changes fuel load.
Diameter, Melt Pool, and Consumption
Diameter drives the melt pool width and heat output. As the pool grows, more wax becomes liquid and feeds the flame, so grams per hour climbs nonlinearly. Wide patio jars often burn faster than slim tapers. Use the measured inner diameter, not the label size. If the candle tunnels, the effective pool stays small and the estimate will be higher than reality until the wick is corrected.
Wax Type and Additive Effects
Wax chemistry changes viscosity and how heat moves through the candle. Paraffin tends to burn stronger, while soy and beeswax often consume slightly less at the same size. Fragrance oils, colorants, or botanicals can increase demand by altering capillary flow and flame stability. Higher scent loads may also require a different wick to prevent sooting and incomplete combustion.
Wick, Container, and Airflow Tuning
A larger wick increases flame intensity and wax draw, shortening runtime. Containers reflect heat, while open pillars shed heat to air, shifting the rate. Outdoor airflow adds flicker and oxygen, usually raising consumption and soot. Shelter candles from gusts for steadier performance. In covered lanterns, reduced wind can extend runtime, but heat buildup may raise the melt pool, so monitor the first few burns.
Session Strategy for Garden Lighting
For safer use, burn in repeatable sessions that fully melt the surface, then extinguish. The calculator converts total hours into sessions so you can schedule refills for paths, patios, or planters. Trim wicks, keep the rim clean, and stop burning if smoking appears. Treat results as a baseline, then refine using a test burn and grams per hour.
FAQs
1) Why does airflow change burn time outdoors?
Wind makes the flame flicker and pull more oxygen. That usually raises wax consumption and can create soot. Use a windbreak, lantern, or sheltered placement to stabilize the flame and get a closer match to the estimate.
2) Should I enter wax weight or wax volume?
Weight is best because it avoids density assumptions. If you only have volume, choose a wax type so the calculator can convert milliliters to grams using typical densities. For custom blends, weigh a sample for accuracy.
3) What diameter should I measure?
Measure the inside diameter at the candle’s widest burn area, usually the container opening. Label sizes can include glass thickness or rim flare. Using the true inner width improves the baseline burn-rate estimate.
4) How accurate is the estimate for my candle?
It is a planning model. Real performance depends on wick tuning, wax blend, dye, fragrance, and trim habits. Run a two-hour test burn, weigh the candle before and after, and compare grams per hour to refine settings.
5) Why does a larger wick reduce total hours?
A larger wick supports a bigger flame and draws more liquid wax. That increases grams per hour, which shortens total runtime. If the candle soots or the flame is tall, a smaller wick may burn cleaner and longer.
6) How can I make candles last longer in the garden?
Use a sheltered spot, keep sessions around three to four hours, and trim the wick to about 5–6 mm before lighting. Avoid very high scent loads and keep the container rim clean so heat stays controlled.