There are four variables you will need to consider in order to determine your requirements

  1. Wire Gauge

    1. This is the physical diameter of your wire, rated using the American Wire Gauge (AWG) scale. Each individual gauge corresponds to a specific millimeter diameter, and is available for your reference

    2. Increasing the gauge of the wire, will increase the current (or amperage) requirement to heat to a desired temperature. Conversely, decreasing the gauge of wire will decrease this requirement.

    3. The gauge of the nichrome wire will also directly correspond to its internal resistance, which is rated as Ohms per Foot. Increasing the gauge will decrease the internal resistance, and decreasing the diameter will increase the resistance. Knowing the wire's resistance will play a role in necessary voltage when temperature and length are kept constant.

    4. When you are trying to calculate the wire gauge, the calculator will display the closest gauge that meets the requirements of the other variables you chose.

      1. Because the wire gauge sizes are incremental, the values of the other variables may not be exact

  2. Length

    1. This is the physical length of your cutting device

    2. By increasing the length you will increase the over all resistance, by decreasing the length you will decrease the overall resistance

    3. When temperature and gauge remain constant, altering the length will affect the voltage requirement of your power supply. As length increases, the resistance increases, and the voltage requirement increases. As length decreases, the resistance decreases, and the voltage requirement decreases.

  3. Temperature

    1. This value is provided in both °F and °C for your reference

    2. This temperature rating is based on experimental values for straight oxidized nichrome wire in a stagnant (not moving) air and not in contact with any other material. Changes in ambient temperature, moving air, and in contact with other materials may alter the true temperature of your wire.

    3. For most styrofoam products, a cutting temperature of around or more than 600°F should be sufficient.

    4. All other values (voltage, length and gauge) play a role in the temperature of the nichrome wire, and is the most important part of any cutting project. It is best to set this value at your minimum requirement to ensure accurate calculations in all other variables.

    5. Once you have your initial set of data from the calculator, and intend on changing the length, voltage or wire gauge, make sure you consult the calculator to see how it will affect both the temperature of your wire as well as the amperage requirement for your power supply

  4. Voltage

    1. This will be the voltage rating of your power supply

    2. When wire gauge and length are kept constant, changing the voltage will affect both temperature of the wire as well as amperage requirement

      1. Increase in voltage, increases temperature and increases amperage requirement

      2. Decrease in voltage, decreases temperature and decreases amperage requirement

      3. When temperature and wire gauge are kept constant, changing the voltage will affect wire length

      4. Increase in voltage, increases the required circuit resistance, and therefore increases the  calculated length

      5. Decrease in voltage, decrease the required circuit resistance, and therefore decreases the calculated length