Tip Calculator Tutorial

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In this tutorial we will create a tip calculator. You can download the category here . Always create the units in the following order: Constants, Variables, Conversions, then Results, because units can refer to other units only after they are created.

We need to create the following units:

Variables: Bill Total, Total People

Conversions: Percentage to Tip, Total Tip Amount

Results: Total to Pay, Total per Person

Create a new category by tapping Menu > Category > New Category. Enter: "Tip" in the Name field and tap OK.

1. Bill Total Unit

Create a new unit by tapping Menu > Unit > New Unit.

• Enter "Bill Total" in the Name field, tap Next button.
• Select Variable in the Type combo box since Bill total is a variable, tap Next button.
• Enter "100" in Value/equation field , tap Next button.
• Enter "$" in the Prefix field, tap Next button.
• Select 2 in Precision combo box , now tap OK button.

We have now created a Bill Total unit. If you have made a mistake, tap Menu > Unit > Edit Unit to correct the mistake.

2. Total People Unit

Now we need to create another variable unit for the number of people to contribute to the tip. So, tap Menu > Unit > New Unit.

• Enter "Total People" in the Name field, tap Next button.
• Select Variable in the Type combo box since Total people is a variable, tap Next button.
• Enter "1" in Value/equation field, tap Next button.
• Since we do not require a prefix or suffix for this unit just tap Next button.
• Select 0 in Precision combo box , now tap OK button.

3. Percentage to Tip Unit

OK, we now have two units, Bill total and Total People. We now need to add two conversion units, Percentage to tap, and Tip amount. So, tap Menu > Unit > New Unit.

• Enter "Percentage to Tip" in the Name field, tap Next button.
• Select Conversion in the Type combo box, tap Next button.
• For the Value/equation value, let’s enter "10", for 10% tip, tap Next button.
• Since this is a percentage unit enter "%" in the Suffix field, tap Next button.
• Select 0 in Precision combo box , now tap OK button.

4. Total Tip Amount Unit

We now need to add one more conversion unit, Total Tip Amount. So, tap Menu > Unit > New Unit.

• Enter "Total Tip Amount" in the Name field, tap Next button.
• Select Conversion in the Type combo box, tap Next button.
• Enter in Factor field "[Bill Total]/100". This is equivalent to [Total Tip Amount] = [Percentage to Tip] * [Bill Total]/100 since converted unit factor is always a multiple of the conversion unit.
  
  Tap Next button. NOTE: To quickly refer to another unit tap Menu > Insert Unit and select the unit from the list.
• Enter "$" in the Prefix field. Tap Next button.
• Select 0 in Precision combo box , now tap OK button.

5. Total to Pay Unit

We should have something like the screen shot on the right. Lets test the tips calculator now. Change Percentage to Tip to 20% (lets be generous), highlight Percentage to Tip and enter 20 then tap Action key. The Total Tip amount changes to $20. Now change Total People to 2. Nothing will happen since we need to find out the bill total, also if we have more than one person paying, we need to know how much each person needs to pay. So tap Menu > Unit > New Unit.

• Enter "Total to Pay" in the Name field, tap Next button.
• Select Result in the Type combo box, tap Next button.
• Enter "[Bill Total]+[Total Tip Amount]" in the Formula field, tap Next button.
• Enter "$" in the Prefix field, tap Next button.
• Select 2 in Precision combo box, now tap OK button.

6. Total per Person Unit

We're nearly finished now. We need to add one more unit, so tap Menu > Unit > New Unit.

• Enter "Total per Person" in the Name field, tap Next button.
• Select Result in the Type combo box, tap Next button.
• Enter "([Bill Total]+[Total Tip Amount])/[Total People]" in the Formula field.
  
  NOTE: It would have been easier to use [Total to Pay]/[Total People] but Result units cannot reference other Result units.
• Enter "$" in the Prefix field, tap Next button.
• Select 2 in the Precision combo box, now tap OK button.

Have a question about this tutorial or CalcConvert, view CalcConvert's forum.