Free Construction Calculators for Your Website
If you run a site for DIYers, homeowners, contractors, landscapers or building-supply buyers, you can add a working project calculator to any page — free. Your readers get a real materials-and-cost estimate without leaving your site.
Free Concrete Slab Calculator Widget
Let your readers size a slab pour — bags vs. ready-mix, base gravel, wire mesh and a cost range — without leaving your page.
Free Gravel Driveway Calculator Widget
Give visitors a driveway/path gravel estimate in cubic yards, tons and truck loads, with a delivered cost range.
Free Fence Calculator Widget
Let readers plan a fence — posts, rails, pickets or panels, concrete, hardware and a DIY vs. installed cost range.
Free Mulch & Landscape Material Calculator Widget
Give garden-project readers a mulch, topsoil or compost estimate with a bulk-vs-bags cost comparison.
Free Paver Calculator Widget
Let readers turn a patio or walkway area into a paver count, base gravel, sand and a cost range.
Free Baluster Calculator Widget
Let readers work out baluster count and code-compliant spacing for a deck or stair railing.
Free Rebar Calculator Widget
Let readers turn a slab size, bar size and spacing into a rebar grid: count, length, weight and cost.
How to add one in three steps
- 1. Open the widget page for the calculator you want, or the embed builder.
- 2. Choose responsive or a fixed width and copy the snippet.
- 3. Paste it into your page's HTML. Done.
Common questions
Are these free to use?
Yes — no account, API key or usage limit, and no link, ads or tracking added to your page. If a calculator is useful to your readers, the one ask is that you add a plain credit link back to it from your page.
Will embedding one slow my site down?
No. Each calculator loads in an iframe so it never blocks your page, and it injects no ad or analytics scripts onto your site. The optional resize script is a few KB and loads asynchronously.
Can I control the size?
You set the width — responsive or a fixed pixel value. Height adjusts to the calculator automatically, with a fixed fallback if the resize script is blocked.
Just want to run the numbers?
The full calculators, with worked examples and formulas: