A candle will burn down perfectly if:

-The wax melts completely up to the rim

-The wick does not turn over too early

-The candle does not produce soot.

It has always required individual experiments to fulfil those mentioned parameters perfectly.
The following indicated sizes are only guide values.

The candle producer is responsible for a good burning down of the candle.

Anyway, if you only know the diameter of the wick you won’t be able to
characterize the burning behaviour. 

For hobby candle makers sufficient in most cases is
up to 60mm candle diameter flatwick 3x9
up to 80mm candle diameter flatwick 3x12

Flat wick

 is the most used wick.
It consists of three braided threads with the indicated number of thin threads.
It doesn’t matter which end of the wick looks up and which one down.
It is suitable for all kinds of wax except stearic acid.

Paraffin-, stearin mixture, rape seed, soy, beeswax-  and gel candles
15 to 25 mm, flat wick 3x7

20 to 60 mm, flat wick 3x9.
good standard wick, fits in many cases

40 to 60 mm, flat wick 3x12
                 Gel candles with thicker wicks tend to produce soot.

60 mm, flat wick 3x15
70 mm, flat wick 3x18
80 mm, flat wick 3x21

For thicker candles or lightly polluted wax you should chose a flat wick 3x27.

Round wick

 is also braided but it has a round cross section.
 The candle foot is marked on the wick and must be respected.
If the wick is inserted correctly the thin threads will spread outwards while the candle burns down.
If it is inserted the other way around the thin threads will spread
inwards and the candle does not burn well.
A round wick is more stable than a flat wick.
As soon as the label has been removed you cannot determine the upper or lower side.

Paraffin-, stearin mixture, rape seed, soy, beeswax-  and gel candles

Up to 25 mm round wick 1
Up to 35 mm round wick 2
Up to 45 mm round wick 3
Up to 50 mm round wick 4
Up to 60 mm round wick 7

Torches and oil lamps round wick 10
Torches and oil lamps round wick 14
Torches and oil lamps round wick 20

Stearine wick

Candle stearin always has an acid reaction. The stearine wicks are prepared for this.
Candel wick without preparation is not able to transport the fluis wax, the candle will extinguish.

 

Torch wick

 is made of cotton – like the other wicks as well. It is braided quite grossly and produces a huge,
wind-resistant flame. It should only be used outdoors.
For garden torches in a flaming platter which is 10cm in size you only need one torch wick.
 If the flaming platter is bigger you’ll need more torch wicks which you insert with
 15cm distance between the wicks. You can also bundle a few wicks.
 This will produce a very huge flame but is not dangerous.

Fibre glass wicks

 hardly wear off while burnt down. Consequently it is necessary that enough liquid material
 (hot wax or lamp oil) flows constantly. These wicks are very suitable for oil lamps.
 If you made a candle with it, the wax level would sink while the wick would stay where it was.
 As a result the candle would produce a lot of soot.
There are some methods where a fibre glass wick keeps burning due to
constantly melting wax. Especially for those wicks it is very important to use clean
 wax/oil since pollutants can accumulate over a long period of time.
 A wick made of cotton burns up and with it the dust particles burn up as well.