The Donald Trump's Wall Calculator is an attempt to simulate the cost of the project and a result of 6 weeks of a research and design process performed by Mateusz Mucha (Omni Calculator's founder) and Tadeusz Zwoliński — a civil engineer from The Warsaw University of Technology. Feel free to tweak any values in the white fields. Click on the "advanced mode" to see everything in greater detail.

It was not an easy task — Donald Trump has not provided a detailed plan - pretty much all we've heard is how high and beautiful it would be. The height changed with time, going from 35 feet to even 80 feet tall. Many aspects of the project make it impractical, if not impossible, to make. In reality, this would also be a massive project, and it's next to impossible to estimate the actual cost (it's been stressed by many experts). Keeping that in mind, we made several assumptions to come up with our model:

The project should be as inexpensive as possible. Even the most straightforward design is prohibitively expensive on this scale. It may not be as beautiful as Mr. Trump would want it to be, but if it's going to save a few billion, we don't think he'd mind it. And it's not like if many Mexicans or Americans would get to look at it anyway. This assumption also means no fancy stuff like video monitoring or even barbed wire.

Multiple simplifications had to be made. We didn't have a team of engineers for two years to make it. We didn't want to write a book about it. You wouldn't want to read it. How shall we transport those large panels? Let's assume we would.

We focused on the main areas related to the construction. We skipped things like the fact that lands need to be purchased, roads need to be built, and the whole project must be designed, administrated, and overseen.

For technical reasons (it's too hot), we can't make the wall on-site. Our best bet is to build it out of precast panels produced at plants as close to the border as possible. Our cheapest bet is to create T-shaped panels, similar to those used to secure the Bagram base and most other US military bases. The difference is that in the case of our structure, a part of the wall is buried in the ground. One reason for that is that our wall is significantly taller. The other is that it makes it harder to dig a tunnel below it. The drawing on the right shows several panels placed next to each other. Compared to regular retaining walls, the foundation may be smaller, as no significant forces are working against the surface. According to our simulations, the wall will survive even extreme winds.

Donald Trump made several claims as to how high the wall would be. It started at 35-45 feet and went up all the way to 90 feet. Interestingly, the claims went higher and higher with time — Someone ought to come up with a theory of the inflationary nature of imaginary walls. We're a bit closer to the ground, so we made it 40 feet high to cut costs.

The panels are reinforced with steel rebar, which takes 1.8% of the total volume. To make things simpler, instead of splitting manufacturing costs into the cost of resources (steel and concrete) and then add a production cost on top of it, we went with a model where we provide a price of one cubic yard of reinforced, precast concrete. We called a few precast plants and asked for prices of reinforced panels and their dimensions. The closest thing to what we've designed was sold to a customer at $635 per cubic yard. We figured that with our scale, we could get it much cheaper and settle at $350.

After the panels are produced, they need to be transported to the border. Looking at the map of concrete plants shown in Bernstein's report, we estimated the average distance from the plant to the construction site would be 150 miles. Again, we went with a conservative rate of $4 per mile (consider the size and weight of these elements and that whatever roads they would build, there wouldn't be proper highways). We simplified things significantly and omitted all potential problems - how would those elements fit on trucks? How would driving on low-quality roads impact the cost?

Assembly. In the purest form, we need an excavator to dig the hole, a (big enough) crane to set it in place, a bulldozer to bury it, and a few regular workers to assist with these works.

Guards. Part of the calculator is devoted to estimating the cost of guards stationed along the wall. We decided to set the number of guards to zero, as some may feel it's not fair to take it into account. Nevertheless, let's go over our reasoning behind the estimation. According to this report, an annual total cost of one policeman is $149,369. It includes the salary, contributions to the Policemen's Annuity and Benefit Fund, healthcare, general liability and worker's compensation insurance, overtime, medicare, uniform allowance, tuition reimbursement, unemployment insurance, and supervision. If you'd like to have the cost of guards taken into account, increase the "placement of guards" counter from 0 to a higher value.

Maintenance. It is always the biggest part of the total cost of the project. It is generally accepted that the construction itself is 10%-20% of any large project with a lifespan of 25 years, the maintenance being the remaining 80-90%. We'll take the lower value since the wall is a fairly simple construction. 80% of the total means it's 400% of the construction costs. 400/25 = 16. Let's give Mr. President a rebate and settle at 15%.

As a bonus, we tried to come up with a list of things that we could do instead of building the wall. Keep in mind that the numbers provided below are correct at the time of writing and may change in the future.

For starters, we could buy 7 billion free meals for homeless people (source). There are 1.56 million homeless folks in the US - we could give all of them three meals a day for the next five years. Or we could build 133 thousand schools in Angola. Or send over 33 million African kids to schools. Don't care for children in Africa? No worries, let's pay for 4-year public college tuition for a quarter of a million Americans (source). Or raise 129,000 American kids from their birth until adulthood (source). Or provide clean drinking water to 437 million people. It may not sound like a problem to people in the Western world, but once you're deprived of clean water, it becomes the issue number one. We could treat 60,000 HIV patients for their entire lives (source).

We could also plant 206 million trees (source), insure nearly 4.7 million people in the US (source) or buy 78 million laptops for school kids (source). Yes, every kid in primary, middle, or high school could carry one and a half computers. Why? Because we could. We could host 4.2 summer Olympics (although I wouldn't recommend doing it even once) (source), build hospitals with 14,500 beds in the US or nearly 730 thousand in India (source for both) (yep, they're good at not spending too much) or take care of 2.8 million veterans (source). Are you a fan of science? How about financing almost 9 Mars Science Laboratory missions? Yeah, we could send the Curiosity rover to the freaking Mars 9 times (source), this is how you make America great. Or finally, if we took John Oliver's counter-proposal into consideration, we could buy 291 million waffle irons, which are nearly as effective in keeping immigrants and drugs away from the country as any wall we could build.

We thought that talking about billions of dollars doesn't mean much to a regular person since these amounts are hard to imagine. We thought, "let's show what that cash could buy instead", but these numbers are still huge. Let's have just one takeaway from this calculator, then: for the money it would take Donald Trump's wall, we could completely solve multiple problems that are far from imaginary.