Mulch & gravel calculator template

Free build guide: Mulch & gravel calculator for WordPress

This guide rebuilds the Mulch & gravel calculator from this site in Gravity Forms: 5 inputs, 4 live results and no submit button. Expect about 27 minutes by hand. The template above is the same form as an import file, and the bundle adds a PDF version of this guide with a screenshot of every setting, plus the stylesheet.

You will end up with:

• Cubic yards
• Cubic feet
• Bags
• Weight (tons)

What you need

• Gravity Forms (any license) — Calculation fields and drop-down values are in core.

Everything here is core Gravity Forms. No add-ons.

1. Create the form

1. Go to Forms → New Form and name it Mulch & gravel.
2. In Form Settings → Form Layout, set the CSS Class Name to fo-live-only. Step 3 uses it to hide the submit button.
3. Leave the form open in the editor; the fields come next.

2. Add the fields, in this order

Field IDs are assigned as you add fields. If yours come out differently, change the {Label:ID} references in the formulas to match your IDs. Settings not mentioned stay at their defaults.

1. Length (ft) · Number · ID 1
Number Format 9,999.99; Default Value 20; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

2. Width (ft) · Number · ID 2
Number Format 9,999.99; Default Value 10; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

3. Depth (in) · Number · ID 3
Number Format 9,999.99; Default Value 3; Description “2–3 in for mulch, 2 in for pea gravel, 4 in for a gravel base.”; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

4. Material · Drop Down · ID 4
Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

Choices (tick show values and enter each value):

• Bark mulch — value 600 (selected by default)
• Wood chips — value 500
• Compost — value 1000
• Topsoil — value 2000
• Pea gravel — value 2600
• Crushed stone / gravel — value 2700
• River rock — value 2650
• Sand — value 2750

5. Bag size · Drop Down · ID 5

Choices (tick show values and enter each value):

• 2 cu ft (standard mulch bag) — value 2 (selected by default)
• 3 cu ft — value 3
• 1.5 cu ft — value 1.5
• 0.5 cu ft (bagged stone) — value 0.5

6. Cubic yards · Number · ID 6
Number Format 9,999.99; Description “Bulk mulch and stone are sold by the cubic yard. Round up.”; Custom CSS Class (Appearance tab) fo-result; tick Enable Calculation, Rounding 2.

( ( {Length:1} * {Width:2} * {Depth:3} / 12 ) / 27 )

7. Cubic feet · Number · ID 7
Number Format 9,999.99; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 1.

( {Length:1} * {Width:2} * {Depth:3} / 12 )

8. Bags · Number · ID 8
Number Format 9,999.99; Description “Round up to whole bags.”; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 1.

( {Length:1} * {Width:2} * {Depth:3} / 12 ) / {Bag size:5}

9. Weight (tons) · Number · ID 9
Number Format 9,999.99; Description “Approximate; wet material weighs more.”; Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 2.

( ( {Length:1} * {Width:2} * {Depth:3} / 12 ) / 27 ) * {Material:4} / 2000

3. Hide the submit button

The results are live, so nothing needs submitting. Add this filter to your theme’s functions.php or a code-snippets plugin; it hides the button on any form carrying the fo-live-only class:

add_filter( 'gform_submit_button', function ( $button, $form ) {
	return str_contains( (string) rgar( $form, 'cssClass' ), 'fo-live-only' ) ? '' : $button;
}, 10, 2 );

Or with CSS alone: .fo-live-only_wrapper .gform_footer { display: none; }

4. Put it on a page and make it look like this

Add the form to any page with the Gravity Forms block, or the shortcode [gravityform id="X" title="false" ajax="false"]. The form inherits your theme’s styles; the classes you set in step 2 are hooks for the look you see on this site:

• fo-result on a calculation field makes it the big teal result panel.
• fo-result fo-result--sub makes the smaller secondary figures.
• fo-segmented on a radio field turns it into a segmented switch.
• Two fields on one row is the editor’s own column layout: drag a field beside another and the row splits in half. No CSS class is needed, and the old gf_left_half Ready Classes are deprecated.

The bundle includes the two stylesheets that implement those classes, with notes on matching your brand colours. Without them the form still works; it just looks like your theme’s default Gravity Forms styling.

How the maths works is explained under “How it’s calculated” on the live Mulch & gravel calculator.