--- title: Cost API description: The API for interacting with the cost of a checkout. api_version: 2026-04 api_name: checkout-ui-extensions source_url: html: >- https://shopify.dev/docs/api/checkout-ui-extensions/latest/target-apis/checkout-apis/cost-api md: >- https://shopify.dev/docs/api/checkout-ui-extensions/latest/target-apis/checkout-apis/cost-api.md --- # Cost API The API for interacting with the cost of a checkout. ### Support Targets (31) ### Supported targets * purchase.​checkout.​actions.​render-before * purchase.​checkout.​block.​render * purchase.​checkout.​cart-line-item.​render-after * purchase.​checkout.​cart-line-list.​render-after * purchase.​checkout.​chat.​render * purchase.​checkout.​contact.​render-after * purchase.​checkout.​delivery-address.​render-after * purchase.​checkout.​delivery-address.​render-before * purchase.​checkout.​footer.​render-after * purchase.​checkout.​header.​render-after * purchase.​checkout.​payment-method-list.​render-after * purchase.​checkout.​payment-method-list.​render-before * purchase.​checkout.​pickup-location-list.​render-after * purchase.​checkout.​pickup-location-list.​render-before * purchase.​checkout.​pickup-location-option-item.​render-after * purchase.​checkout.​pickup-point-list.​render-after * purchase.​checkout.​pickup-point-list.​render-before * purchase.​checkout.​reductions.​render-after * purchase.​checkout.​reductions.​render-before * purchase.​checkout.​shipping-option-item.​details.​render * purchase.​checkout.​shipping-option-item.​render-after * purchase.​checkout.​shipping-option-list.​render-after * purchase.​checkout.​shipping-option-list.​render-before * purchase.​thank-you.​announcement.​render * purchase.​thank-you.​block.​render * purchase.​thank-you.​cart-line-item.​render-after * purchase.​thank-you.​cart-line-list.​render-after * purchase.​thank-you.​chat.​render * purchase.​thank-you.​customer-information.​render-after * purchase.​thank-you.​footer.​render-after * purchase.​thank-you.​header.​render-after ## StandardApi The base API object provided to `purchase` extension targets. * **cost** **CartCost** **required** The cost breakdown for the current checkout, including subtotal, shipping, tax, and total amounts. These values update as the buyer progresses through checkout and costs like shipping and tax are calculated. ### CartCost * subtotalAmount The sum of all line item prices at the current step of checkout, before shipping and taxes are applied. Use this value to display the base cost of the items the buyer purchased. ```ts SubscribableSignalLike ``` * totalAmount The minimum total at the current step of checkout. Costs not yet calculated, such as shipping on the information step, aren't included. Gift cards and store credits are excluded from this total. ```ts SubscribableSignalLike ``` * totalShippingAmount The total shipping cost after shipping discounts have been applied. The value is \`undefined\` if shipping hasn't been calculated yet, such as when the buyer is still on the information step. ```ts SubscribableSignalLike ``` * totalTaxAmount The total tax the buyer can expect to pay, or the total tax already included in product and shipping prices (for tax-inclusive regions). The value is \`undefined\` if taxes haven't been calculated yet. ```ts SubscribableSignalLike ``` ### SubscribableSignalLike Represents a reactive signal interface that provides both immediate value access and subscription-based updates. Enables real-time synchronization with changing data through the observer pattern. This interface extends \`ReadonlySignalLike\` with deprecated fields that are still supported for backwards compatibility. * current The current value of the signal. Equivalent to \`.value\`, accessing this property subscribes to changes when used in a reactive context. ```ts T ``` * destroy Cleans up the subscription and releases any resources held by this signal. After calling \`destroy()\`, the signal stops receiving updates from the main thread. ```ts () => Promise ``` * subscribe Subscribes to value changes and calls the provided function whenever the value updates. Returns an unsubscribe function to clean up the subscription. Use to automatically react to changes in the signal's value. ```ts (fn: (value: T) => void) => () => void ``` * value The current value of the signal. This property provides immediate access to the current value without requiring subscription setup. Use for one-time value checks or initial setup. ```ts T ``` ### Money * amount The decimal amount of the price. For example, \`29.99\` represents twenty-nine dollars and ninety-nine cents. ```ts number ``` * currencyCode The three-letter currency code in \[ISO 4217]\(https://en.wikipedia.org/wiki/ISO\_4217) format. ```ts CurrencyCode ``` ### CurrencyCode ```ts 'AED' | 'AFN' | 'ALL' | 'AMD' | 'ANG' | 'AOA' | 'ARS' | 'AUD' | 'AWG' | 'AZN' | 'BAM' | 'BBD' | 'BDT' | 'BGN' | 'BHD' | 'BIF' | 'BMD' | 'BND' | 'BOB' | 'BOV' | 'BRL' | 'BSD' | 'BTN' | 'BWP' | 'BYN' | 'BZD' | 'CAD' | 'CDF' | 'CHE' | 'CHF' | 'CHW' | 'CLF' | 'CLP' | 'CNY' | 'COP' | 'COU' | 'CRC' | 'CUC' | 'CUP' | 'CVE' | 'CZK' | 'DJF' | 'DKK' | 'DOP' | 'DZD' | 'EGP' | 'ERN' | 'ETB' | 'EUR' | 'FJD' | 'FKP' | 'GBP' | 'GEL' | 'GHS' | 'GIP' | 'GMD' | 'GNF' | 'GTQ' | 'GYD' | 'HKD' | 'HNL' | 'HRK' | 'HTG' | 'HUF' | 'IDR' | 'ILS' | 'INR' | 'IQD' | 'IRR' | 'ISK' | 'JMD' | 'JOD' | 'JPY' | 'KES' | 'KGS' | 'KHR' | 'KMF' | 'KPW' | 'KRW' | 'KWD' | 'KYD' | 'KZT' | 'LAK' | 'LBP' | 'LKR' | 'LRD' | 'LSL' | 'LYD' | 'MAD' | 'MDL' | 'MGA' | 'MKD' | 'MMK' | 'MNT' | 'MOP' | 'MRU' | 'MUR' | 'MVR' | 'MWK' | 'MXN' | 'MXV' | 'MYR' | 'MZN' | 'NAD' | 'NGN' | 'NIO' | 'NOK' | 'NPR' | 'NZD' | 'OMR' | 'PAB' | 'PEN' | 'PGK' | 'PHP' | 'PKR' | 'PLN' | 'PYG' | 'QAR' | 'RON' | 'RSD' | 'RUB' | 'RWF' | 'SAR' | 'SBD' | 'SCR' | 'SDG' | 'SEK' | 'SGD' | 'SHP' | 'SLL' | 'SOS' | 'SRD' | 'SSP' | 'STN' | 'SVC' | 'SYP' | 'SZL' | 'THB' | 'TJS' | 'TMT' | 'TND' | 'TOP' | 'TRY' | 'TTD' | 'TWD' | 'TZS' | 'UAH' | 'UGX' | 'USD' | 'USN' | 'UYI' | 'UYU' | 'UYW' | 'UZS' | 'VES' | 'VND' | 'VUV' | 'WST' | 'XAF' | 'XAG' | 'XAU' | 'XBA' | 'XBB' | 'XBC' | 'XBD' | 'XCD' | 'XDR' | 'XOF' | 'XPD' | 'XPF' | 'XPT' | 'XSU' | 'XTS' | 'XUA' | 'XXX' | 'YER' | 'ZAR' | 'ZMW' | 'ZWL' ``` ## use​Subtotal​Amount() A `Money` value representing the subtotal value of the items in the cart at the current step of checkout. ### Returns * **Money** ### ### Money * **amount** **number** The decimal amount of the price. For example, `29.99` represents twenty-nine dollars and ninety-nine cents. * **currencyCode** **CurrencyCode** The three-letter currency code in [ISO 4217](https://en.wikipedia.org/wiki/ISO_4217) format. ## use​Total​Shipping​Amount() Returns a `Money` value representing the total shipping a buyer can expect to pay at the current step of checkout. This value includes shipping discounts. Returns undefined if shipping has not been negotiated yet, such as on the information step. ### Returns * **Money | undefined** ## use​Total​Tax​Amount() Returns a `Money` value representing the total tax a buyer can expect to pay at the current step of checkout or the total tax included in product and shipping prices. Returns undefined if taxes are unavailable. ### Returns * **Money | undefined** ## use​Total​Amount() Returns a `Money` value representing the minimum a buyer can expect to pay at the current step of checkout. This value excludes amounts yet to be negotiated. For example, the information step might not have delivery costs calculated. Applied gift cards and store credit are excluded. ### Returns * **Money** ### ### Money * **amount** **number** The decimal amount of the price. For example, `29.99` represents twenty-nine dollars and ninety-nine cents. * **currencyCode** **CurrencyCode** The three-letter currency code in [ISO 4217](https://en.wikipedia.org/wiki/ISO_4217) format. ## Related [Reference - Targets](https://shopify.dev/docs/api/checkout-ui-extensions/targets) [Reference - Components](https://shopify.dev/docs/api/checkout-ui-extensions/components) [Reference - Configuration](https://shopify.dev/docs/api/checkout-ui-extensions/configuration) [Learn - Tutorials](https://shopify.dev/apps/checkout)