Bid the run and the panel, not the charger.

There is no flat hang fee. Use this page: a short indoor 48 A job on a spare slot often lands near $1,200–$1,400 at the default rates. Switch the location to a detached garage, add a 60-foot trench, and pick a service upgrade — the same charger becomes a several-thousand-dollar job. That gap is the whole product.

48 A continuous × 1.25 = 60 A breaker. Copper #6 usually carries that ampacity; a long run may upsize to hold 3% voltage drop at 240 V. The result panel shows the gauge and the calculated drop for the feet you entered.

Only if the existing service does not have the headroom. Enter the service rating and a honest existing-load estimate. If the new breaker is larger than the unused capacity, the tool flags it — it does not decide the upgrade for you, and it is not a permit load calculation. A 200 A service already estimated at 190 A of existing load has only 10 A of headroom; a 48 A charger needs a 60 A breaker, so that job gets flagged even though the panel itself has a free slot.

Ampacity and voltage drop are two different limits. A 48 A charger's 60 A breaker is carried by #6 copper on ampacity alone, but at 160 feet that #6 run would sit past the 3% voltage-drop budget at 240 V. The calculator checks both and upsizes to #4 (1.98% drop at 160 ft) whenever the shorter-run wire would fail the drop check — the wire size shown is whichever limit binds for the feet you entered, not just the breaker size.

At the default rates, a 48 A indoor hang on a spare slot with a 25-foot run prices near $1,263. Move the same charger to a detached garage with a 70-foot run, a 60-foot trench, and a service upgrade, and it prices near $4,587 — largely trench labor and restoration, the extra outdoor labor rate, and the 8 hours a service upgrade adds to the panel line. Same charger, almost 3.6× the price, because the job is not the charger.

The result panel prices your entered job against a fixed reference — the same wage, burden, overhead, and margin, but a 48 A indoor hang, 20-foot run, spare panel slot, no trench, no hardware. At the defaults that baseline prices near $1,189, so a $1,263 quote reads as about 6% over it. That reference is the "easy garage" number a customer often has in mind from a flat-fee ad; the ratio shows how far your actual job's numbers move it, not whether either price is right.