Every number on this site is an estimate made by people who are not standing in your house. This page explains where those numbers come from, what they leave out, and when you should ignore them.
Last reviewed 14 September 2026. This page changes when our method changes, and the date above moves with it.
Where the numbers come from
We don’t have a proprietary pricing database, and we’re not going to imply we do. What we have is published data, read carefully: manufacturer and retailer list prices for materials, published labor-rate and cost-range data from trade and industry sources, permit schedules from municipal fee tables, and performance standards from bodies like the Department of Energy where a spec is what drives the cost.
The standard we hold ourselves to is that a figure should be traceable. You should be able to see what it rests on and roughly when it was true, so where a guide prints a cost table, the caption says both.
Older guides on this site don’t all meet that standard yet. Some carry ranges we’d now want attributed more tightly, and we’re working back through them. If you hit one where the sourcing looks thin, that’s a fair criticism and we’d like to hear it.
Why you get a range and not a number
A single figure precise to the dollar is the most confident-sounding and least useful thing a cost guide can print. It averages jobs that have nothing in common. Swapping a water heater in an accessible basement and relocating one to a different wall with new venting are not the same project, and the average of the two describes neither.
Ranges are less satisfying to read. They’re also the honest shape of the answer. What we try to do alongside the range is tell you which end of it you’re likely on, because that’s the part you can act on.
What a range usually doesn’t include
Most published cost figures quietly assume the job goes to plan. Ours try to flag when it might not, but unless a guide says otherwise, assume these sit outside the headline number:
- What the job uncovers. Rot behind the tile, aluminum wiring, a subfloor that has to come up. This is the most common reason a real invoice beats an estimate, and no cost guide can price it in advance.
- Permits and inspection. These vary by municipality more than almost anything else, and sometimes don’t apply at all.
- Disposal. Hauling the old thing away is its own line item more often than people expect.
- The work you decide to do while you’re already in there. Not a hidden cost exactly, but it’s where budgets go.
Region moves the price more than anything else
Labor rates for the same trade can differ by a factor of two between a dense metro and a rural county. That gap is usually wider than the difference between the cheap and expensive version of the job itself, which is why a national range is a starting point and not an answer. It tells you whether you’re looking at a weekend project or a five-figure one. It cannot tell you what you’ll pay, because we don’t know your zip code, your local permit office, or how busy the trades are where you live this month.
What “DIY cost” means here
When a guide splits DIY from professional, the DIY figure is materials plus tools plus consumables. Two things distort that, and both are worth saying out loud.
Your time isn’t free, even though it never appears on a receipt. A job that saves a few hundred dollars and eats two weekends is a real trade-off, and it’s yours to make — we’d just rather put the hours next to the savings than show only one of them.
Tool cost depends entirely on what you already own. Buying a tile saw for one bathroom changes the arithmetic; renting it for a weekend barely registers. Where a tool is expensive enough to matter, the guide says whether renting makes more sense.
And some jobs we’ll tell you not to do yourself regardless of the savings. Gas lines, structural work, anything inside the service panel. Not because DIY is beneath anyone, but because the failure mode there isn’t a wasted Saturday.
Numbers go stale, and we say when
Material prices move. Sometimes slowly, sometimes in a step, when a tariff lands or supply tightens. A cost guide that doesn’t tell you when it was written is asking you to trust a number of unknown age. Guides here are dated, cost tables state what period they describe, and when a figure moves enough to change the answer we update the guide rather than let the old number age quietly in place.
Nobody pays for a number
This site earns through affiliate links to retailers, set out in full in the Affiliate Disclosure. A commission has never moved a figure and never will. There’s no version of this site where publishing an inflated cost is worth more than publishing the right one, because the entire value of a cost guide is that the number is the number.
We also don’t sell your project to contractors. Some cost sites are lead-generation businesses with an article attached — the estimate exists to get you into a form, and the form is the actual product. If you ever land on a page here that wants your phone number before it will tell you what something costs, something has gone badly wrong.
Get quotes anyway
Two or three, from licensed local contractors, before you commit to a budget. Use what’s here to judge whether a quote sits in a sane range, and to ask sharper questions when it doesn’t. That’s the job this site can genuinely do.
Tell us when we’re wrong
If a number here doesn’t match what you were quoted, we want to know — and your quote is better evidence than anything we have. Get in touch. Corrections change the guide.