Candle Burn Time Calculator
How this candle burn time calculator works
This calculator estimates how many hours a candle will burn based on three key inputs:
- Wax weight (in grams) – how much usable wax the candle contains.
- Burn rate per wick (grams of wax used per hour by a single wick).
- Number of wicks – how many wicks are burning at the same time.
The basic idea is simple: if you know how quickly each wick uses wax and how many wicks are burning, you can work out how much wax is consumed in an hour. Dividing the total wax by this hourly consumption gives an estimated burn time.
The core formula
The calculator uses the following relationship:
Estimated burn time (hours) = Wax weight (g) ÷ (Burn rate per wick (g/hour) × Number of wicks)
In MathML form, the same formula looks like this:
Where:
- is the estimated burn time in hours.
- is the total wax weight in grams.
- is the burn rate per wick in grams per hour.
- is the number of wicks.
Step-by-step example calculation
Imagine a container candle with the following characteristics:
- Wax weight: 300 g
- Burn rate per wick: 5 g/hour
- Number of wicks: 2
- First, work out how much wax is burned per hour by all wicks combined:
5 g/hour × 2 wicks = 10 g/hour total consumption. - Next, divide the total wax weight by the total hourly consumption:
300 g ÷ 10 g/hour = 30 hours.
So this candle is expected to burn for around 30 hours under the same conditions as the test burn used to measure the burn rate.
How to measure burn rate per wick
To get realistic results from the calculator, it helps to measure an actual burn rate for your wick and wax combination instead of guessing. A simple home or workshop test looks like this:
- Weigh the candle before burning. Record the total weight.
- Burn for a known time. For example, burn for 2–3 hours in a draft-free, room-temperature environment.
- Extinguish and cool. Let the candle cool completely so the wax solidifies.
- Weigh again. Subtract the cooled weight from the starting weight to find grams of wax consumed.
- Divide by hours. Burn rate per wick = (wax used in grams) ÷ (hours burned) ÷ (number of wicks).
Example: If a double-wick candle starts at 500 g, then after 3 hours of burning it weighs 470 g, it has used 30 g of wax. The combined burn rate is 30 g ÷ 3 hours = 10 g/hour. Dividing by 2 wicks gives 5 g/hour per wick.
Interpreting your burn time estimate
Once you calculate burn time, you can use the result in a few practical ways:
- Planning usage sessions: If your candle has an estimated 40-hour burn time and you typically burn for 2 hours an evening, you can expect roughly 20 evenings of use.
- Designing new candle sizes: Makers can adjust wax fill weights and wick choices to hit target burn times (for example, a 20-hour travel tin versus a 60-hour large jar).
- Pricing products: Longer-burning candles often justify higher prices. Knowing an approximate burn time per candle helps you compare value across sizes and formulas.
- Creating usage guidelines: Labels like “Burn for 3–4 hours per session, up to 45 total hours” are easier to justify when you have a calculated baseline.
Remember that burn time is an estimate, not a guarantee. Real-world variations in environment, user behavior, and manufacturing tolerances will change the actual outcome.
Typical burn time ranges by candle type
The table below shows approximate burn time ranges for common container candles when wicked and burned properly. Your exact results will differ, especially if you change wick size, fragrance load, or container shape.
| Candle type / size (container) | Approx. wax weight | Typical wax type | Typical wick setup | Typical burn time range | Notes |
|---|---|---|---|---|---|
| Small travel tin (4 oz) | 90–120 g | Soy or soy blend | 1 wick | 15–25 hours | Lower fragrance loads and smaller flames help extend burn time. |
| Medium jar (8–9 oz) | 180–230 g | Soy, paraffin, or blends | 1–2 wicks | 30–50 hours | Dual wicks give stronger scent but reduce total hours versus single-wick options. |
| Large jar (12–16 oz) | 300–450 g | Paraffin or soy blend | 2–3 wicks | 40–70 hours | More wicks improve melt pool but increase wax use per hour. |
| Beeswax container (medium) | 200–250 g | Beeswax | 1 wick | 30–55 hours | Beeswax typically burns slower than soy or paraffin, with a smaller, denser flame. |
| Tea light | 10–15 g | Paraffin or soy | 1 wick | 3–6 hours | Very sensitive to drafts; may tunnel or extinguish early in poor holders. |
You can compare your calculated burn time with these ranges. If your estimate is far outside typical values for similar candles, consider rechecking your burn rate measurement or wick choice.
Key factors that change burn time
The formula assumes that the burn rate and conditions stay consistent, but in practice many variables affect how long a candle actually lasts:
- Wick type and size: Larger or more open wicks draw more wax and produce a bigger flame, increasing burn rate.
- Wax type: Paraffin often burns faster and hotter; soy tends to be moderate; beeswax is usually slower-burning.
- Fragrance load and additives: Heavy fragrance, dyes, and certain additives can change how cleanly and quickly the candle burns.
- Container shape and diameter: Wide, shallow containers encourage a larger melt pool and higher hourly wax consumption.
- Environment: Drafts, air conditioning vents, and nearby fans tilt the flame and speed up wax use; very warm rooms can soften wax and increase consumption.
- User behavior: Burning for very short sessions can cause tunneling; running candles for extremely long sessions can overheat containers and shorten life.
Assumptions and limitations
This tool is designed as a planning aid rather than a precise laboratory instrument. It makes several important assumptions:
- Constant burn rate: It assumes that the burn rate per wick stays the same over the life of the candle, even though burn rate can change slightly as the wax level drops or as the container heats up.
- Even melt pool: It assumes wicks are centered and properly sized so the candle forms an even melt pool without tunneling or excessive hang-up on the sides.
- Stable environment: It assumes the same general conditions as your test burn (no strong drafts, moderate room temperature, standard indoor altitude and humidity).
- Consistent user behavior: It assumes that each burn session is within recommended safety limits and that the wick is trimmed regularly.
Because of these assumptions, the result should be read as a best-effort estimate. For safety, always follow standard candle safety guidelines such as not burning unattended, keeping candles away from flammable materials, and avoiding excessively long continuous burns.
Using the calculator for candle making and inventory planning
Candle makers can use burn time estimates to design products and manage stock more efficiently:
- Product development: Adjust fill weights and wick combinations until calculated burn times hit your targets (for example, a “20-hour mini” or “70-hour signature jar”).
- Batch planning: Estimate how many hours you are putting on the shelf when you pour a batch of candles. This can help with forecasting customer usage and repeat purchase cycles.
- Value positioning: Compare cost per hour of burn across different sizes and wax types when setting prices.
- Labeling and marketing: Use conservative burn time ranges in marketing materials, clearly noting that they are approximate and depend on following burn instructions.
Frequently asked questions
How many hours of burn time do you get per gram of wax?
There is no single fixed value because burn rate depends on wick, wax, and container, but many well-wicked container candles fall somewhere around 0.4–0.7 hours of burn time per gram of wax. The calculator lets you refine this by using your measured burn rate rather than a generic rule of thumb.
Why is my candle burning faster than the estimate?
Common reasons include oversized wicks, strong drafts, burning for very long sessions, or using a wax blend that burns hotter than expected. Check that the wick is appropriately sized, keep it trimmed to about 5 mm, and avoid placing the candle near open windows, fans, or vents.
Is it safe to burn a candle until all the wax is gone?
Most safety guidelines recommend stopping use when about 1 cm of wax remains, especially in glass containers, to reduce the risk of overheating or breaking the container. The burn time you calculate is for the usable wax; do not plan to burn beyond the manufacturer’s safety recommendations.
How long should I burn a candle in one session?
A common recommendation is between 2 and 4 hours per session for container candles. Shorter sessions may cause tunneling, while much longer sessions can overheat the container or accelerate soot buildup. Always follow any limits printed on the candle’s label.
Do different waxes really change burn time that much?
Yes. Beeswax typically burns slower than soy, which in turn often burns slower than paraffin, assuming similar wicks and containers. However, wick choice can override wax differences, so the best way to know is to perform a controlled test burn and use the measured burn rate in this calculator.
Next steps and related tools
After estimating burn time, you may want to refine your candle design further by adjusting wick sizes, wax types, or container dimensions, then repeating your test burns. Pairing this calculator with tools like a wax weight or volume converter, a wick size guide, or a cost-per-candle calculator can help you build consistent, reliable products with clear “hours of enjoyment” messaging for your customers.