Skylight tools

The gap between an estimate and a bid is the site. A skylight quote depends on whether a rafter is in the way, whether the attic has ducts or wiring above the ceiling, how steep the roof is, and how long the light shaft needs to be. No calculator asks those questions well.

Where tools genuinely help: sizing. As a rule of thumb the industry uses, a skylight is sized relative to the room's floor area and how much daylight you want — and the practical result is that people usually under-size. Walking through a sizing exercise before you meet a salesperson stops you from being talked into whatever unit is on the truck.

The most valuable thing you can prepare is a written scope you hand to every bidder: number of units, type (fixed, venting, tubular), whether the opening exists, whether you want the interior finished, and who pulls the permit. Identical scope in means comparable numbers out.

Treat any tool that asks for your phone number before showing a number as a lead form, not a calculator.

How to choose

Use estimates as a sanity check only

If a bid is triple the national range, ask what's driving it. Sometimes there's a real reason — pitch, tile roof, long shaft.

Write one scope, send it to everyone

The most common reason quotes look wildly different is that they describe different work.

Size before you shop

Decide roughly how much glass you want before a salesperson decides for you.

Don't trade your phone number for a range

Free calculators that gate the number are lead generation. The number you get afterward is rarely better.