Three different things get called an “online estimate”
1. A national-average calculator. You enter a room size and a ZIP code and it returns a figure derived from nationwide averages. It has never seen your house. Useful for orientation and nothing else — San Diego labor runs meaningfully above national averages, so the number is usually low before anyone has looked at anything.
2. Lead-generation bait. The “estimate” exists to collect your phone number. The real number arrives later from whichever contractors bought your details, and you find out how many bought them when your phone starts ringing.
3. A measured estimate. The tool measures the actual property, applies published contractor cost data for your region, and shows you what it did. That is what this page is about, and it is what we build.
How we calculate yours
We measure the roof, we do not guess it. For roofing we pull your roof from aerial and elevation data — planes, pitch and surface area. On a real San Diego property we measured 1,366 square feet at a 15.3° pitch. On a flat commercial roof nearby, 1,914 square feet at 1.7°. That measurement replaces the usual shortcut of multiplying floor area by a fudge factor.
Why that matters more than it sounds: on that 1,366 sq ft house, the conventional guess for an 1,800 sq ft home implies a 2,070 sq ft roof, and would have priced at roughly $7,200–$12,400. The measured roof prices at about $4,800–$8,200. The guess was $2,400 too high. Guessing is not the conservative choice; it is wrong in both directions, and an inflated number costs you a contractor you might have wanted.
Prices come from a contractor cost book, not from us. Unit costs are taken from the 2026 National Construction Estimator — the same class of published data professional estimators use — then adjusted for San Diego, with materials and labor adjusted separately because local labor varies far more than material does. You see the materials and labor split, and the date the pricing was current.
Scope questions change the number, because they should. Moving walls, plumbing or gas lines is the single biggest swing on a kitchen or bathroom, so we ask. A kitchen priced as cabinets, counters and appliances is shown to you as exactly that, itemised, so a component estimate is never mistaken for a whole-project price.
What our estimate cannot see
This is the part most estimate tools leave out, and it is the part that decides whether a number survives contact with a real job.
None of that is visible from above and none of it is in a cost book. It is why an estimate is a planning range rather than a quote, and why a contractor still walks the property before anyone signs anything.
Why we will not publish an accuracy percentage
Because an honest one does not exist. Accuracy depends on how recent the imagery is for your address, whether the scope you described matches the work actually needed, and above all on the hidden conditions listed above. A single percentage would average across all of that and mislead you in both directions. It would be marketing, not measurement.
What we can tell you is where every number came from, which is what the rest of this page is.
What we do about the gap
Most tools stop at “a contractor will tell you the real number later.” That is a fine place to stop if the business model is selling your details to contractors. It is not much help to you.
On roofing, flooring and exterior work, one licensed San Diego contractor will match our estimate, apples to apples. Apples to apples is doing real work in that sentence: it means identical scope. It is what separates the job we priced from a job that grew once someone opened the roof and found a third layer. If the scope genuinely changes, the number changes — and a contractor worth hiring will show you exactly why.
You are also never handed to a crowd. One contractor, and only when you ask for one.
How to judge any online estimate, including ours
An estimate that hides its method is asking you to trust a number instead of understanding it.