Car depreciation calculator template

Free build guide: Car depreciation calculator for WordPress

This guide rebuilds the Car depreciation calculator from this site in Gravity Forms: 5 inputs, 5 live results and no submit button. Expect about 30 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:

• Value in that many years
• Value today
• Lost over the period
• Per year over the period
• Share of new price left (%)

What you need

• Gravity Forms (any license) — Calculation fields are in core; the exponent and if blocks need GP Advanced Calculations.
• GP Advanced Calculations (Gravity Wiz) — Exponents, functions and date math in calculation fields. The formulas in this template use its syntax. Part of Gravity Perks; needs the Spellbook plugin active as well.

The formulas below use GP Advanced Calculations syntax: exponents, functions or date math that core calculation fields cannot do. Install and activate it, with its Spellbook parent plugin, before you start; without it every result shows 0.

1. Create the form

1. Go to Forms → New Form and name it Car depreciation.
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. Price when new · Number · ID 1
Number Format Currency; Default Value 35000; Description “What it sold for new, not what you paid used.”; Layout: half width, on the same row as its neighbor (drag the field beside it in the editor; no CSS class needed).

2. Age now (years) · Number · ID 2
Number Format 9,999.99; Default Value 0; Description “0 for a new car.”; Layout: half width, on the same row as its neighbor (drag the field beside it in the editor; no CSS class needed).

3. First-year drop (%) · Number · ID 3
Number Format 9,999.99; Default Value 20; Description “15–25% for most cars; 30%+ for luxury brands and EVs; under 15% for Toyota and Honda trucks and SUVs.”; Layout: half width, on the same row as its neighbor (drag the field beside it in the editor; no CSS class needed).

4. Drop each later year (%) · Number · ID 4
Number Format 9,999.99; Default Value 15; Description “12–18% is typical, slowing as the car gets older.”; Layout: half width, on the same row as its neighbor (drag the field beside it in the editor; no CSS class needed).

5. Years from now · Number · ID 5
Number Format 9,999.99; Default Value 5.

6. Value in that many years · Number · ID 6
Number Format Currency; Description “Private-sale value in average condition; dealers offer less.”; Custom CSS Class (Appearance tab) fo-result; tick Enable Calculation, Rounding 0.

if( {Age:2} + {Ahead:5} == 0 ):
{Price:1}
else:
( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) )
endif;

7. Value today · Number · ID 7
Number Format Currency; Layout: half width, on the same row as its neighbor (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 0.

if( {Age:2} == 0 ):
{Price:1}
else:
( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( {Age:2} - 1 ) )
endif;

8. Lost over the period · Number · ID 8
Number Format Currency; Description “The real cost of owning it for those years, before fuel, insurance and repairs.”; Layout: half width, on the same row as its neighbor (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 0.

if( {Age:2} == 0 ):
{Price:1} - ( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) )
else:
( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( {Age:2} - 1 ) ) - ( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) )
endif;

9. Per year over the period · Number · ID 9
Number Format Currency; Layout: half width, on the same row as its neighbor (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 0.

if( {Age:2} == 0 ):
( {Price:1} - ( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) ) ) / {Ahead:5}
else:
( ( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( {Age:2} - 1 ) ) - ( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) ) ) / {Ahead:5}
endif;

10. Share of new price left (%) · Number · ID 10
Number Format 9,999.99; Layout: half width, on the same row as its neighbor (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.

if( {Age:2} + {Ahead:5} == 0 ):
100
else:
( {Price:1} * ( 1 - {First:3} / 100 ) * ( 1 - {Yearly:4} / 100 ) ^ ( ( {Age:2} + {Ahead:5} ) - 1 ) ) / {Price:1} * 100
endif;

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 colors. Without them the form still works; it just looks like your theme’s default Gravity Forms styling.

How the math works is explained under “How it’s calculated” on the live Car depreciation calculator.