Depending on which calculator you are using there are several fields in the input form. These field can be used to define your option or option structure (multiple options.
Type: Define option type, can be either call or put
Amount: Define the amount of option contracts. Please note that 1 means 1 option contract, so 1 corresponds to 100 actual options.
Short/Long: Define if the option is short (=sold) or long (=bought)
Price: Define the option contract price (or price per 100 actual options)
Strike: Define the option strike
(The following fields are not always present)
Expiration: Define expiration date of option
Define target date: Use the calendar to indicate at which point in time you wish to know the value of the options, implied volatility and so on
Current price underlying value: Define what the current price is of the stock, security or whatever instrument the options are based on
Target price underlying value: Define what your estimate is of the price of the underlying value at the target date you defined above
Once all field are filled in, use the submit button (Estimate value / calculate / ...) to calculate the result. After filling in new values in any of the fields, the submit button should be used to update the result.
Use the "Add option"button to add more options for your calculation (when multiple options are supported). The red cross can be used to delete options and the checkbox can be used to exclude or include options from the calculation. Note that with the checkbox the results are automatically updated. This allows you to easily determine differences in outcome when you leave out or put in specific options in your strategy.