What's a Good Profit Margin for a Deck Contractor?

Short answer: there isn't one universal number, and any page that hands you a flat “X% is the industry standard” figure is giving you a number that fits someone else's business, not necessarily yours.

Why there's no single right answer

Target margin depends on your overhead, your risk on a given job, and your local market, three things that vary contractor to contractor. A company with higher fixed overhead needs a higher margin just to cover it before any profit starts. A contractor taking on a job with real site-condition risk (difficult access, an unusual structural situation) has a reason to price in more cushion than a straightforward build. Two contractors in different markets can both be “right” at different margin targets.

How to actually set your own number

Start from your overhead, not from a percentage you've seen somewhere. Work out what it actually costs to run your business in a year, independent of any single job, then work out what you need your margin to cover: that overhead, plus the profit you actually want to take out of the business. That calculation gives you a target margin that's yours, not borrowed from an average that may not reflect your real costs.

A margin that's too low doesn't show up right away

The risk with guessing low is that it doesn't look wrong on any one job, the job still closes, the client's happy, the crew gets paid. It shows up months later, when overhead that was never fully covered has quietly eaten the profit a string of “successful” jobs should have produced. A deliberately set target margin is what catches that before it happens, not after.

Checking your number against the job, every time

Once you've set a target margin, the real value is in using it consistently, on every bid, not just the ones that feel tight.