How much money do you spend each week for work lunches? Do the math. The number may shock you. 

But, for just a few dollars and several minutes of your time, you can prepare something delicious at home. 

Buying lunch can run anywhere from $4 for, say, a cup of soup and a roll, to $15 (or more) for a restaurant lunch or some take-out sushi. Let’s just call the average daily lunch about $10, which gets you a fancy sandwich with some chips and a soda.

Make that same fancy sandwich at home, and you’re spending remarkably less. Using ingredients you buy at a grocery store, a sandwich that a deli charges $6 for would probably cost you less than $2 to make at home. Add in a buck for a bag of chips and a buck for a drink, and we’re at $4, less than half the cost of typical weekday lunch out.

If you’re a bulk shopper, and if you bag your own chips and fill a reusable bottle with water for refreshment, you could probably get the cost down to less than $2.

And that’s not even the cheapest way to go. You could make a pasta lunch for less. But we’ll go with an average brown-bag cost of $4, for some wiggle room. At $4 for lunch, that’s a 60 percent savings over eating out. If you save $6 a day, five days a week, that’s $30 a week, $120 a month, and almost $1,500 a year.

So is it cheaper? Very much so. Whether the money you’re saving is worth the extra effort of making your own lunch — that’s something only you can answer. But $1,500 can cover a year’s electricity bill.

Add in the fact that the lunch you make at home will almost always be healthier than the lunch you buy out, and you might end up saving some money on medical costs, too.

We’re not telling you to go cold turkey on the sushi rolls and personal pizzas or your favorite lunch spot. We’re only challenging you to brown-bag it once a week: on Tuesdays. 

Don’t leave your lunch prep for the morning madness; do it the night before. Also, make sure you have all the ingredients on hand before Monday night rolls around by jotting them down on the weekly grocery list. 

Changing a long-standing habit is never easy. Are you up to the challenge?