What a Supercharger site costs to build, by stall count

The first number anyone wants about a Supercharger site is what it costs to build. Published ranges tend to be national and wide, which makes them hard to use: a range of "$750K to $1.1M for eight stalls" contains both a project that pencils and one that does not.

This post takes the model's CAPEX stack apart line by line, totals it at four stall counts, and then shows the piece that varies by state — the one-time sales tax, which moves the same eight-stall build by about $116,000 depending on where it is built.

The four lines#

Total project cost in the model is built from four inputs, not one:

1. Hardware per stall. The dispenser plus its share of the power cabinet. The model's default is $62,500 per stall.
2. Install per stall. Trenching, conduit, concrete, switchgear, and labor. The default is $75,000 per stall — more than the hardware it connects. On sites where the electrical service is far from the parking field, install is the line that decides the budget.
3. Utility upgrade. What the utility charges to bring adequate capacity to the property: a transformer, a service drop, a line extension. It runs from roughly zero to six figures depending on what is already at the site, so the model keeps it as its own input rather than burying it in install. The defaults carry it at zero, which is why a real quote for this line is one of the most consequential numbers a site owner can obtain.
4. Contingency. A percentage on the subtotal, defaulting to 10%, because construction estimates move between bid and completion.

Two structural notes. Contingency applies to the subtotal, so it scales with everything above it. And sales tax is not inside the subtotal — it lands separately, as a one-time charge in month 1 of the cash flow.

Totals at four stall counts#

Hardware and install at the defaults come to $137,500 per stall, or $151,250 after contingency. Carried across four common site sizes, with California's sales-tax treatment applied for illustration:

These scale linearly because the defaults do. Real projects rarely do: the utility upgrade is lumpy, and a site that needs a new transformer for stall nine carries a step change no per-stall figure predicts. The build-cost tool runs this table for any stall count and any state, and the scenario wizard prices a specific address with a real utility-upgrade quote in place of the zero default.

The line that varies by state#

Sales tax on a project this size is not a rounding error, and states treat it in two different ways that compound.

First, the rate. Across the 51 state tax profiles in the model, the combined rate applied to charging hardware runs from 0% — Montana, New Hampshire, and Alaska file no state sales tax — to 10.55%, with a mean near 6.7%.

Second, the base. Most states tax the hardware and exempt separately stated installation labor. Four in the library — Washington, Ohio, Minnesota, and Hawaii — tax install labor as well, which nearly doubles the taxable base on a project where install exceeds hardware.

Those two rules together produce the spread. The same eight-stall build:

• $1,210,000 all-in in Alaska, Montana, or New Hampshire — no sales tax line at all.
• $1,326,050 all-in in Washington, where a 10.55% rate applies to hardware and install labor.

That is $116,050 of difference on an identical scope of work, decided entirely by the state's tax code. It is also a cost that does not appear in any national cost range, because a national range cannot express it.

What this figure is and is not#

Total project cost is the number that starts a conversation, not the one that ends it. Two qualifiers matter.

It is not what leaves the bank on day one. If the project is financed, the down payment is — the model's default is 20%, so an eight-stall California build calls for roughly $251,000 at close, with the balance amortizing over the loan term as an operating cost.

And it is not what determines the outcome. A site's result is set far more by its utility tariff and its utilization than by its build cost. Across the filed tariffs in the library, the same reference site's all-in electricity cost varies by a factor of about 8.5 between the cheapest and most expensive territory — a spread that swamps the $116,050 the tax code contributes. The utility rankings show that ordering, and what a flat blended electricity rate hides works through why.

Incentives move the net figure too, in both directions and with their own timing rules. The incentives checker records what is currently filed by jurisdiction, and NEVI funding for a privately owned site covers how grant money enters the cash flow.

The methodology page lists every default in this post with its source and effective date.

All figures here are model outputs under stated assumptions, not quotes, guarantees, or advice. Hardware pricing, labor rates, and tax rules change; verify current values against primary sources and a real contractor bid before relying on any number.