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 Soil Calculator Widget
Let gardening readers work out how much soil a raised bed, garden bed or lawn needs, in yards and bags.
Free River Rock Calculator Widget
Let landscaping readers work out how many tons or bags of river rock or decorative rock a bed needs.
Free Paver Calculator Widget
Let readers turn a patio or walkway area into a paver count, base gravel, sand and a cost range.
Free Drywall Calculator Widget
Let readers turn a room size into sheets of drywall, mud, tape, screws and a cost range.
Free Baluster Calculator Widget
Let readers work out baluster count and even 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.
Free Flooring Calculator Widget
Let readers turn their rooms into boxes of LVP, laminate or hardwood, carpet yardage, underlayment, trim and a cost.
Free Tile Calculator Widget
Let readers work out tiles, boxes, thinset and grout for a floor or wall, grout joint included.
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.
Install notes
- Plain HTML: paste the snippet where you want the calculator to appear.
- WordPress: add a “Custom HTML” block and paste the snippet in. Avoid the “Paragraph” block — it strips iframes.
- Squarespace / Wix / Webflow: add an “Embed” or “Custom Code” / “HTML” element and paste the snippet.
- The last line (
embed.js) is optional — it just auto-sizes the frame height. You only need it once per page even with several calculators.
Sizing & responsiveness
Set the width to 100% to fill the column it sits in, or a fixed pixel value for a sidebar or narrow layout. Height is handled for you: with embed.js the frame grows and shrinks to fit the calculator (including after someone runs an estimate); without it, the frame keeps a fixed height and everything still works, just with an inner scrollbar on small screens.
Common questions
Are these free to use?
Yes — no account, API key or usage limit, and no ads or tracking added to your page. The embed code ends with a one-line credit link back to the calculator; please keep it, as it is what keeps these calculators free.
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: