Sketching out the real cost of a new backyard deck
The first truly warm day of the year has a way of making you look at your backyard with fresh eyes. Suddenly, that patchy bit of lawn looks exactly like the perfect spot for a deck. You can picture it: a grill, a table with friends, a place to read in the sun. And then comes the big, fuzzy, intimidating question: what would that actually cost?
It’s a project that can feel like a huge unknown. Online articles give you wide ranges, and it’s hard to know where your dream fits in. But you don’t need a contractor to get a decent first look. All you need are your own rough measurements and a place to sketch out the numbers.
Start with the basics: Size and materials
The biggest factors in the cost of a deck are its size and the material you choose. Most estimates start with a price per square meter. Let’s say you’re thinking of a simple 4-by-5-meter deck. First, you’d find the area.
Next, you need a cost estimate. Recent guides for 2026 suggest that professionally installed decking can range from around €300 to €600 per square meter, depending on the material. Pressure-treated wood is on the lower end, while composite materials are higher.
Let’s start with a mid-range estimate and see what that looks like. Here’s the math, live — you can change the dimensions or the cost per square meter to match your own space and research.
Factoring in labor
Unless you’re building it entirely yourself, materials are only part of the equation. Labor is a significant chunk of the budget. Some contractors bundle it into their square-meter price, while others break it out. Estimates suggest labor can add €150 to €350 per square meter to the total project cost.
Let’s add that to our calculation. We can create a variable for the total area to make the math clearer. Notice how changing the dimensions in the first section will now update everything that follows.
Don’t forget the extras (and a buffer)
This is where back-of-the-napkin math often stops, and where real-world budgets get into trouble. A flat platform is one thing, but you’ll probably need stairs, railings, and maybe some built-in lighting. Then there are costs for permits, which can be a few hundred euros, and finishing touches like stain or sealant.
It’s hard to price these perfectly upfront, so a good strategy is to add a line item for them. More importantly, every big project needs a contingency fund — a buffer for the unexpected. A 10-15% buffer is a safe bet to prevent surprises from derailing the project.
Let’s build out the final estimate. This is the number that gives you a realistic target for savings or financing, turning a vague daydream into an actual plan.
Seeing the final number isn’t meant to be discouraging. It’s the opposite. It’s the first step to making a real decision. Now you have a tangible goal you can plan around, and you can see which levers have the biggest impact. Maybe a slightly smaller deck or a different material brings it into reach this year. The best plans start with clear numbers.
Numbers stick around if you want to keep iterating — try it at app.calnote.eu.