First, I realize that this question was asked back in Jan 2017, but it was difficult to obtain useful data because the details of construction were not available.

This question arises as a spin-off of a recent question about the cost-effectiveness of the wall. It seems to me that before one can discuss the cost-effectiveness, it is necessary to have a handle on the "cost".

I am NOT interested in speculation about motivations of people, or how specific individuals would behave.

Almost two years later, is there any better estimate for the cost of a completed border wall project?

  • 6
    I voted to close this question because the cost of a future project, on the government dime, is impossible to know before some major milestones in its construction process, let alone before the ground breaking or appropriations have cleared. We don't know what the design is going to be, or how much it will cost, largely because we don't know what the design will be, or what hurdles will appear before it. For reference, look to the High Speed Rail in California. Commented Dec 27, 2018 at 20:30
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    @BobE the leading focus is the lack of a design, even base concept, and the actual appropriations. The additional hurdles are the cost of the "ecological impact" surveys that will be required. Commented Dec 27, 2018 at 23:27
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    @DrunkCynic: There's no lack of a design... the problem is that there are too many competing ones, because the appropriations process hasn't yet winnowed the field. Debating a set of 3 or 4 designs is possible, a set of three or four hundred is far less amenable to comprehensive analysis.
    – Ben Voigt
    Commented Dec 31, 2018 at 22:18
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    @Giter you appear to have no experience with government procurement or project management.
    – phoog
    Commented Jan 2, 2019 at 5:14
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    @DrunkCynic Those things only add uncertainty, they don't make it impossible to determine a cost range. We can say with certainty that it would cost more than $1B. We can say with certainty that it would cost less than $1T. Cost estimating is just trying to find how narrow we can get those bounds.
    – David Rice
    Commented Jan 2, 2019 at 15:46

5 Answers 5


There are no estimates on the cost of a completed US-Mexico border wall, because the project has not yet been detailed and designed.

  • 3
    This is patently false: there are lots of estimates. E.g. eu.azcentral.com/story/news/politics/border-issues/2018/08/06/… Which ones are accurate is of course another matter. Commented Dec 31, 2018 at 16:16
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    Paul are any of the estimates based on anything other than speculation of what is to be built ( materials) , where it is to be built, how high, how many miles, costs of property access , etc, etc. Even the president hasn’t decided what the construction will be, how long etc
    – BobE
    Commented Jan 1, 2019 at 1:25
  • See this answer by @WhatRoughBeast Commented Jan 2, 2019 at 16:19

Not that hard to get a rough back of the envelope unofficial estimation, all we have to do is look at other border barriers, and there is no shortage of these. I'll go with a cheap option:

Hungarian border barrier

This is a wire fence with razor wire on top though, not the fancy "big beautiful wall" that President Trump announced. This would be a lot more expensive.

The border between Hungary and Serbia is 175 kilometres (109 mi) long (...) The fence, which features concertina wire, is being built by contractors and a deployment of 900 soldiers at a cost of 30 billion forints ($106 million) for the 4-meter (13-foot) fence and the construction of two camps to house asylum applicants.

That's a cost of USD 605 000 per kilometer.

Mexiso-US border is 3145 km, that gives $1.9 billion.

GDP per capita is about 2x higher in the US than in Hungary, and online cost of living estimator says 2.5x higher... I'll go with a 2.5x higher cost in the US for a total of USD 4.7 Billion. Pretty close to the 5B figure I've heard, give or take.

That's 0.125% of the $4 trillion federal budget.

  • So that’s the your cheap estimate and thank you it is properly identified as unofficial. Do you think that the president would be satisfied with a wire fence? My point is that no engineer is going to begin to develop an estimate until the construction parameters have been established.
    – BobE
    Commented Jan 1, 2019 at 1:39
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    @BobE "Do you think that the president" => Trying to predict what Trump is going to do next is rather risky...
    – bobflux
    Commented Jan 1, 2019 at 10:04
  • @BobE False. Multiple designs have been developed and mister Trump has visited the designs, pointed at them and talked about them. (proof). Of course engineers are going to make mock-ups, they want to build a wall because it's a big project with a good payday.
    – JJJ
    Commented Jan 1, 2019 at 16:54
  • @JJJ - of course trump looked and pointed - but did anyone ( president or congress) declare " yes this is the design, now figure out how to build it from the Gulf of Mexico to the Pacific" ? I don't know how to say it any plainer, until the parameters of the project are established (or acceptable alternate parameters) you can't provide credible engineered cost estimates.
    – BobE
    Commented Jan 2, 2019 at 3:56
  • @ Peufeu That is the point- until Trump makes a firm decision, the design parameters are unknown making it impossible to provide a firm cost estimate
    – BobE
    Commented Jan 2, 2019 at 4:02

What’s next you might ask? When combined with the funds provided in FY 2017 and FY 2018, if funded at $5B in FY 2019 (emphasis added) DHS expects to construct more than 330 miles of border wall in the U.S. Border Patrol’s highest priority locations across the Southwest border.

DHS is positioned to construct 215 miles of Border Patrol’s highest priority border wall miles including:

  • ~5 miles in San Diego Sector in California
  • ~14 miles in El Centro Sector in California
  • ~27 miles in Yuma Sector in Arizona
  • ~9 miles in El Paso Sector in New Mexico
  • ~55 miles in Laredo Sector in Texas
  • ~104 miles in Rio Grande Valley Sector in Texas

Source: Walls Work

$5 billion/215 is 23255813.9535.

The (FY 2019) estimated cost of a completed 215 miles of U.S.-Mexico border wall made by the primary source is $23,255,813.9535/1 mile.


Obviously "better" is in the eye of the beholder when it comes to estimates, but Rep. Kevin McCarthy has introduced a bill to "fully fund" the wall, which claims the cost in additional (unauthorized) spending to be $23.4 billion.

However, this simply tops up $1.6 billion in authorized spending to $25 billion, a pretty round number.

But, given that this is on the high end of the previous estimates, and would thus be something like a "statement against interest" (presumably it would be in Republicans' best interest to pretend the wall will be inexpensive), I would argue this estimate has at least some value.

  • Have you read mccarthy's bill? He provides no information on the length of the wall, no references to materials of construction and cites no engineering costs.
    – BobE
    Commented Jan 2, 2019 at 4:24
  • ref the last paragraph, asking for a huge envelop might also be a bargaining position : by asking for $25b in hypothetical negociations with the Democrats, the Republicans might later settle for, say, $12b and stilll pretend to have made a concession.
    – Evargalo
    Commented Jan 2, 2019 at 12:06

First, I assume you are talking about the land border wall here. If you wanted to truly seal off the US-Mexico border with a wall, you would have to build a wall along the beaches of California, Texas, Louisiana, Mississippi, Alabama and Florida, too.

Secondly, it isn't clear from your question whether you are asking about the construction cost or the operating cost. While I speculate that you meant to ask about the construction cost, the lion's share of the cost will be maintenance and operation.

For that, some back-of-the-envelope calculation will result in dramatically large numbers.

I am assuming that this wall would be secured similar to the wall between Germany and East Germany in the 1980s. That wall was far from impenetrable, but we can probably call it fairly good in terms of security (not that any wall is ever "good" in a moral sense). In some areas, such as between San Diego and Tijuana, the US-Mexico border is designed very similar to the East German wall.

Of course, the East German border wall was very short (~300 km, I believe, plus another ~180km around Berlin), but also maintained by a much smaller country.

The East German border wall was staggeringly expensive, and some people argue that it was a major factor in East Germany's eventual bankruptcy.

A wall like that requires watch towers approximately a km apart, give or take (in some cases, they were spaced much closer together). Each tower was manned by approximately 3 guards (soldiers in the case of East Germany) at a time, operating in shifts 24/7. So after taking weekends, vacations, training, sick days etc. into account, you will need approximately 12 or so full-time guards per mile, probably more than that. Keep in mind that this number is based on a country with no qualms about using landmines, automated guns, and shoot-to-kill orders. Hopefully, any wall in the US would be more humane. That would drive up your manpower requirements.

You also need probably roughly an equal number of support personnel, doing anything from logistics to/from all those towers, vehicle maintenance, human resources, management, etc.

Note that these guards cannot actually be replaced with technology. Cameras, drones etc. don't do much good when the nearest border patrol agent is an hour's drive away!

Translating that to the US-Mexico land border of 3145 km, that means you need nearly 80000 border guards and support. Just for the land border to Mexico - not even including the coasts or the border with Canada. For comparison: the whole Border Patrol today only has about 20,000 people - and that's for all borders, coastlines, airports, and a lot of inland stuff.

That would be roughly half the size of the US Marine Corps.

On top of that, the wall is not a "build it and forget it" construction project; it needs continuous ongoing construction work. That's why the vast majority of Trump's wall replaced existing sections, and added only a few new miles to the wall.

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