This lunch savings calculator can help you figure out how much you can save by bringing a lunch to work instead of eating out, in such a way to spend less money and increase your personal savings. There is in depth information on this topic below the form.
How does this lunch savings calculator work?
This personal finance tool allows you to simulate how much you can actually save by bringing your lunch to work from home instead of eating out. To do such calculation you have to assume the following figures:

The home bagged lunch cost (A).

The eating out lunch cost (B).

No. of work lunches per month (C).

For how long you assume to save by this way (D).

An assumed annual return rate (E).
The algorithm behind this lunch savings calculator applies these steps and formulas:

Find the estimated monthly savings F = (B  A) * C

Calculate the lunch savings per year G = F * 12

Determine the total lunch savings within the time frame specified H = G * D

Forecast the amount of money in the savings account at the end of the period I=(1+E*0.01)*G (〖(1+E*0.01)〗^D1)/(E*0.01)

Find the total interest earned from depositing the money saved J = I – H.
Example of a calculation
Assuming the following figures:
Home bagged lunch cost (A) = $5
Eating out lunch cost (B) = $7.5
No. of work lunches per month (C) = 20
For how long to save (D) = 5 years
Annual return rate will be (E) = 5%.
Results:
■ If you take your food from home instead of eating out while you are at work you can save per month $50.00
■ Per year that means you can save in average $600.00, which in a 5 years time is equivalent $3,000.00 principal saved.
■ If you deposit your annual savings of $600.00, at be beginning of each of the 5 years you can have a final balance in your account of $3,481.15.
■ The total interest you will have earned is $481.15.
19 Apr, 2015