Pool volume calculator template

Free build guide: Pool volume calculator for WordPress

This guide rebuilds the Pool volume calculator from this site in Gravity Forms: 8 inputs, 7 live results and no submit button. Expect about 45 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:

• Gallons
• Gallons
• Gallons
• Litres
• Litres
• Litres
• Average depth (ft)

What you need

• Gravity Forms (any license) — Calculation fields and conditional logic 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 Pool volume.
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. Pool shape · Radio Buttons · ID 1
Custom CSS Class (Appearance tab) fo-segmented.

Choices (tick show values and enter each value):

• Rectangle — value rect (selected by default)
• Round — value round
• Oval — value oval

2. Length (ft) · Number · ID 2
Number Format 9,999.99; Default Value 32; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Conditional Logic (Advanced tab): Show this field if Pool shape is Rectangle..

3. Width (ft) · Number · ID 3
Number Format 9,999.99; Default Value 16; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Conditional Logic (Advanced tab): Show this field if Pool shape is Rectangle..

4. Diameter (ft) · Number · ID 4
Number Format 9,999.99; Default Value 24; Conditional Logic (Advanced tab): Show this field if Pool shape is Round..

5. Length (ft) · Number · ID 5
Number Format 9,999.99; Default Value 30; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Conditional Logic (Advanced tab): Show this field if Pool shape is Oval..

6. Width (ft) · Number · ID 6
Number Format 9,999.99; Default Value 15; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed); Conditional Logic (Advanced tab): Show this field if Pool shape is Oval..

7. Shallow end depth (ft) · Number · ID 7
Number Format 9,999.99; Default Value 3; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

8. Deep end depth (ft) · Number · ID 8
Number Format 9,999.99; Default Value 8; Description “Same as the shallow end for a flat-bottom pool.”; Layout: half width, on the same row as its neighbour (drag the field beside it in the editor; no CSS class needed).

9. Gallons · Number · ID 9
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Rectangle..

{Length:2} * {Width:3} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 7.5

10. Gallons · Number · ID 10
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Round..

{Diameter:4} * {Diameter:4} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 5.9

11. Gallons · Number · ID 11
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Oval..

{Length:5} * {Width:6} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 6.7

12. Litres · Number · ID 12
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Rectangle..

{Length:2} * {Width:3} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 7.5 * 3.785

13. Litres · Number · ID 13
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Round..

{Diameter:4} * {Diameter:4} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 5.9 * 3.785

14. Litres · Number · ID 14
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 0; Conditional Logic (Advanced tab): Show this field if Pool shape is Oval..

{Length:5} * {Width:6} * ( ( {Shallow:7} + {Deep:8} ) / 2 ) * 6.7 * 3.785

15. Average depth (ft) · Number · ID 15
Number Format 9,999.99; Custom CSS Class (Appearance tab) fo-result fo-result--sub; tick Enable Calculation, Rounding 1.

( ( {Shallow:7} + {Deep:8} ) / 2 )

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 Pool volume calculator.