Price Calculations

The "Price Calculations" plugin will allow you to recalculate the price of the product based on what the customer enters / selects on the product page.

• Define formulas to calculate product prices based on customer input (custom item fields), product data, or fixed values.
• Multiple formulas with conditions: the plugin uses the first formula whose condition matches.
• Automatic tax handling with fine-grained control via :notax, :withtax, and :optional modifiers.
• Supports characteristics/variants (the {price} tag reflects the selected variant's price).
• Supports product options (the {price} tag includes option costs).
• Live price preview on the product page via AJAX, updating as the customer changes fields.
• Detailed calculation metadata exposed on the product object for use in view overrides and JavaScript.

Easy and quick !

1. Download the plugin on our website
2. Install it on your Joomla website (extension manager)
3. Enable the "HikaShop Price calculations" plugin via the Joomla plugins manager
4. Edit the plugin and enter the different formulas you want to use in it.

• This HikaShop Price Calculations plugin is compatible with all the editions of HikaShop
• HikaShop 5.1.0 or newer required, HikaShop 6.4.0 or newer for calculation metadata
• Compatible with PHP 7.4 minimum
• GPL v3
• No limit of time
• No limit of use

Formulas are mathematical expressions that can reference product data, custom fields, and the current price. You can add several formulas in the plugin settings. For each product, the plugin evaluates them in order and uses the first one whose condition (if any) is met.

Available tags:

• {price} : the product's unit price (takes into account the selected variant and options)
• {product_quantity}, {cart_product_quantity} : stock or cart quantity
• {fieldname} : any product custom field or item custom field by its column name (e.g. {product_width}, {product_height}, {product_weight}, or custom fields like {material_surcharge})
• {currency_id} : the ID of the currency in which the price is currently displayed (useful in conditions to apply different formulas per currency)
• {currency_rate} : the exchange rate of the current display currency relative to the main currency (e.g. 1 for USD if USD is the main currency, 24 for CZK if 1 USD = 24 CZK). Use this to make fixed amounts scale with currency conversion.
• Numbers (integers and decimals), operators (+, -, *, /), parentheses
• PHP functions: abs(), strlen(), mb_strlen(), substr(), trim(), str_word_count(), boolval(), empty(), decimal()

Tag modifiers:

• {field:notax} : prevents tax from being applied to this field's value
• {field:withtax} : forces tax to be applied even if the field is auto-detected as non-price (like a quantity)
• {field:optional} : if the field is empty or missing, use 0 instead of skipping the formula
• {field:optional:5} : same, but use 5 as the default value
• Modifiers can be combined: {surcharge:optional:0:notax}

Examples:

• {product_width} * {product_height} * 0.5 + {price} : area-based pricing added to the base price
• {price} * {cart_product_quantity} * 0.9 : 10% discount applied to total
• {price} + {engraving_fee:optional:0:notax} : optional flat fee without tax
• {price} + (10 * {currency_rate}) : adds a 10 main-currency surcharge that scales with the display currency (e.g. +$10 USD or +240 CZK when 1 USD = 24 CZK)

Multi-currency conditions:

You can use {currency_id} in conditions to apply different formulas depending on the customer's currency. For example, use condition {currency_id} == 2 to match CZK only, with a fallback formula (no condition) for all other currencies.

Conditions:

Each formula can have a condition. The condition uses the same tags and is evaluated as a boolean expression. If it returns false, the formula is skipped and the next one is tried. Example condition: {product_width} > 0 or {material} == 'premium'.

When the plugin calculates a price, it stores detailed metadata on the product object at $product->price_calculation. This data is available in any HikaShop view override (cart, checkout, order, etc.) and can be used to display a breakdown of the calculation.

Available properties:

• $product->price_calculation->formula : the original formula template (e.g. {product_width} * {product_height} * 10 + {price})
• $product->price_calculation->formula_resolved : the formula with values substituted (e.g. 50 * 30 * 10 + 25.00)
• $product->price_calculation->price_before / price_before_with_tax : the price before calculation
• $product->price_calculation->price_after / price_after_with_tax : the final calculated price
• $product->price_calculation->taxes : the tax rates applied
• $product->price_calculation->fields : array of field details (see below)

Each entry in the fields array contains:

• name : the field name (e.g. "product_width")
• raw_value : the original value from the product or customer input
• resolved_value : the numeric value before tax
• taxed : boolean, whether tax was applied to this field's value
• tax_id : the tax category ID used (when taxed)
• value_used : the final value used in the formula (after tax if applicable)

Example view override (cart):

if(!empty($product->price_calculation->fields)) {
    echo '<ul class="calculation_breakdown">';
    foreach($product->price_calculation->fields as $field) {
        echo '<li>' . $field->name . ': ' . $field->raw_value;
        if($field->taxed) echo ' (incl. tax)';
        echo '</li>';
    }
    echo '</ul>';
}

On the product page, the plugin makes an AJAX call each time the customer changes a field value. The response includes the calculated price and full metadata, which you can use in custom JavaScript.

Listening to calculation updates:

The plugin calls window.hikashop.refreshCalculatedPrice when fields change. You can register your own listener via the HikaShop AJAX event system:

window.Oby.registerAjax(['hkContentChanged'], function(params) {
    // Triggered after variant selection or field change
    // The calculated price div has already been updated at this point
});

AJAX response format:

The AJAX response is a JSON object with:

• price : formatted price string (respects the "Show taxed price" setting)
• price_with_tax : formatted price with tax
• price_without_tax : formatted price without tax
• price_value : raw numeric price value
• price_value_with_tax : raw numeric price with tax
• formula : the formula object that was used
• calculation : the full calculation metadata (same structure as $product->price_calculation on the server side)

Example: custom price display with breakdown:

// Override the default price update to add a breakdown
var originalRefresh = window.hikashop.refreshCalculatedPrice;
window.hikashop.refreshCalculatedPrice = function() {
    // Call the original function first
    var form = document.querySelector('form[name="hikashop_product_form"]');
    if(!form) return;
    var formData = window.Oby.getFormData(form, false);
    var data = window.Oby.encodeFormData({formData: JSON.stringify(formData)});
    window.hikashop.xRequest(calculationUrl, {mode:'POST', data:data}, function(xhr) {
        var resp = Oby.evalJSON(xhr.responseText);
        // Display the price
        var html = resp.price;
        // Add breakdown if calculation data is available
        if(resp.calculation && resp.calculation.fields) {
            html += '<ul>';
            resp.calculation.fields.forEach(function(f) {
                html += '<li>' + f.name + ': ' + f.raw_value + '</li>';
            });
            html += '</ul>';
        }
        document.getElementById('hikashop_product_price_with_options_main').innerHTML = html;
    });
};

The "Price Calculations" plugin will allow you to recalculate the price of the product based on what the customer enters / selects on the product page.

• Define formulas to calculate product prices based on customer input (custom item fields), product data, or fixed values.
• Multiple formulas with conditions: the plugin uses the first formula whose condition matches.
• Automatic tax handling with fine-grained control via :notax, :withtax, and :optional modifiers.
• Supports characteristics/variants (the {price} tag reflects the selected variant's price).
• Supports product options (the {price} tag includes option costs).
• Live price preview on the product page via AJAX, updating as the customer changes fields.
• Detailed calculation metadata exposed on the product object for use in view overrides and JavaScript.

Easy and quick !

1. Download the plugin on our website
2. Install it on your Joomla website (extension manager)
3. Enable the "HikaShop Price calculations" plugin via the Joomla plugins manager
4. Edit the plugin and enter the different formulas you want to use in it.

• This HikaShop Price Calculations plugin is compatible with all the editions of HikaShop
• HikaShop 5.1.0 or newer required, HikaShop 6.4.0 or newer for calculation metadata
• Compatible with PHP 7.4 minimum
• GPL v3
• No limit of time
• No limit of use

Formulas are mathematical expressions that can reference product data, custom fields, and the current price. You can add several formulas in the plugin settings. For each product, the plugin evaluates them in order and uses the first one whose condition (if any) is met.

Available tags:

• {price} : the product's unit price (takes into account the selected variant and options)
• {product_quantity}, {cart_product_quantity} : stock or cart quantity
• {fieldname} : any product custom field or item custom field by its column name (e.g. {product_width}, {product_height}, {product_weight}, or custom fields like {material_surcharge})
• {currency_id} : the ID of the currency in which the price is currently displayed (useful in conditions to apply different formulas per currency)
• {currency_rate} : the exchange rate of the current display currency relative to the main currency (e.g. 1 for USD if USD is the main currency, 24 for CZK if 1 USD = 24 CZK). Use this to make fixed amounts scale with currency conversion.
• Numbers (integers and decimals), operators (+, -, *, /), parentheses
• PHP functions: abs(), strlen(), mb_strlen(), substr(), trim(), str_word_count(), boolval(), empty(), decimal()

Tag modifiers:

• {field:notax} : prevents tax from being applied to this field's value
• {field:withtax} : forces tax to be applied even if the field is auto-detected as non-price (like a quantity)
• {field:optional} : if the field is empty or missing, use 0 instead of skipping the formula
• {field:optional:5} : same, but use 5 as the default value
• Modifiers can be combined: {surcharge:optional:0:notax}

Examples:

• {product_width} * {product_height} * 0.5 + {price} : area-based pricing added to the base price
• {price} * {cart_product_quantity} * 0.9 : 10% discount applied to total
• {price} + {engraving_fee:optional:0:notax} : optional flat fee without tax
• {price} + (10 * {currency_rate}) : adds a 10 main-currency surcharge that scales with the display currency (e.g. +$10 USD or +240 CZK when 1 USD = 24 CZK)

Multi-currency conditions:

You can use {currency_id} in conditions to apply different formulas depending on the customer's currency. For example, use condition {currency_id} == 2 to match CZK only, with a fallback formula (no condition) for all other currencies.

Conditions:

Each formula can have a condition. The condition uses the same tags and is evaluated as a boolean expression. If it returns false, the formula is skipped and the next one is tried. Example condition: {product_width} > 0 or {material} == 'premium'.

When the plugin calculates a price, it stores detailed metadata on the product object at $product->price_calculation. This data is available in any HikaShop view override (cart, checkout, order, etc.) and can be used to display a breakdown of the calculation.

Available properties:

• $product->price_calculation->formula : the original formula template (e.g. {product_width} * {product_height} * 10 + {price})
• $product->price_calculation->formula_resolved : the formula with values substituted (e.g. 50 * 30 * 10 + 25.00)
• $product->price_calculation->price_before / price_before_with_tax : the price before calculation
• $product->price_calculation->price_after / price_after_with_tax : the final calculated price
• $product->price_calculation->taxes : the tax rates applied
• $product->price_calculation->fields : array of field details (see below)

Each entry in the fields array contains:

• name : the field name (e.g. "product_width")
• raw_value : the original value from the product or customer input
• resolved_value : the numeric value before tax
• taxed : boolean, whether tax was applied to this field's value
• tax_id : the tax category ID used (when taxed)
• value_used : the final value used in the formula (after tax if applicable)

Example view override (cart):

if(!empty($product->price_calculation->fields)) {
    echo '<ul class="calculation_breakdown">';
    foreach($product->price_calculation->fields as $field) {
        echo '<li>' . $field->name . ': ' . $field->raw_value;
        if($field->taxed) echo ' (incl. tax)';
        echo '</li>';
    }
    echo '</ul>';
}

On the product page, the plugin makes an AJAX call each time the customer changes a field value. The response includes the calculated price and full metadata, which you can use in custom JavaScript.

Listening to calculation updates:

The plugin calls window.hikashop.refreshCalculatedPrice when fields change. You can register your own listener via the HikaShop AJAX event system:

window.Oby.registerAjax(['hkContentChanged'], function(params) {
    // Triggered after variant selection or field change
    // The calculated price div has already been updated at this point
});

AJAX response format:

The AJAX response is a JSON object with:

• price : formatted price string (respects the "Show taxed price" setting)
• price_with_tax : formatted price with tax
• price_without_tax : formatted price without tax
• price_value : raw numeric price value
• price_value_with_tax : raw numeric price with tax
• formula : the formula object that was used
• calculation : the full calculation metadata (same structure as $product->price_calculation on the server side)

Example: custom price display with breakdown:

// Override the default price update to add a breakdown
var originalRefresh = window.hikashop.refreshCalculatedPrice;
window.hikashop.refreshCalculatedPrice = function() {
    // Call the original function first
    var form = document.querySelector('form[name="hikashop_product_form"]');
    if(!form) return;
    var formData = window.Oby.getFormData(form, false);
    var data = window.Oby.encodeFormData({formData: JSON.stringify(formData)});
    window.hikashop.xRequest(calculationUrl, {mode:'POST', data:data}, function(xhr) {
        var resp = Oby.evalJSON(xhr.responseText);
        // Display the price
        var html = resp.price;
        // Add breakdown if calculation data is available
        if(resp.calculation && resp.calculation.fields) {
            html += '<ul>';
            resp.calculation.fields.forEach(function(f) {
                html += '<li>' + f.name + ': ' + f.raw_value + '</li>';
            });
            html += '</ul>';
        }
        document.getElementById('hikashop_product_price_with_options_main').innerHTML = html;
    });
};