Functional cookies remember preferences such as a chosen language, currency or display setting. They save visitors from repeating the same choices and can support features such as chat or embedded media.
However, “functional” is a descriptive category, not a legal exemption. Whether a cookie needs consent depends on its actual purposes, how it is used and the applicable rules. Remembering a selected language is different from tracking browsing history to personalise content or advertising.
Functional cookies are cookies used to remember settings or provide particular website features. They are also called functionality cookies or preference cookies, although category names vary between websites and consent tools.
When a visitor selects a display preference, the website may save a corresponding value in a cookie. On a later page or visit, it reads that value and applies the setting again.
Functional cookies can have different lifetimes:
Session cookies: Usually expire when the browser session ends, although session-restoration features can affect this.
Persistent cookies: Remain until their expiry, deletion or earlier removal by the browser.
Purpose and duration are separate questions. A session cookie is not automatically necessary, and a persistent cookie does not automatically require consent solely because it lasts longer. Retention still matters when assessing necessity and any applicable exemption.
Common functional cookies examples involve remembering a choice the visitor has made. The same feature can also involve other processing, so its name alone is not enough to classify every associated cookie.
Feature | Remembered preference or function | What to consider |
|---|---|---|
Language | The language selected by the visitor. | Remembering an explicit choice differs from selecting content using an inferred profile. |
Currency and region | The selected currency or store region. | Location tracking and advertising targeting are separate purposes. |
Theme and accessibility | Dark mode, text size or contrast settings. | Check the applicable preference or appearance rules and limit storage to the stated purpose. |
Chat and video | Continuity of a requested chat or media setting. | Assess additional analytics and advertising uses separately. |
Login and shopping cart | Maintaining authentication or the current cart. | These may be strictly necessary when required to deliver the service requested by the visitor. |
The same feature can involve different types of cookies depending on how it is implemented and what data it processes.
For example, a video service may use cookies for playback preferences alongside analytics cookies or advertising identifiers. The need to play a video does not automatically exempt those additional uses. Each purpose needs assessment, and non-exempt purposes require the appropriate permission before they operate.
The key distinction in functional cookies vs necessary cookies is whether the storage is essential to a requested service or provides an additional preference or feature.
Category | Main purpose | Example |
|---|---|---|
Necessary | Deliver a service requested by the visitor. | Maintain an authenticated session or current shopping cart. |
Functional | Remember preferences or support additional features. | Remember a selected display setting. |
Analytics | Measure how people use the website. | Associate page visits with a visitor identifier. |
Marketing | Support advertising, targeting or related measurement. | Recognise a visitor for remarketing. |
These categories describe purposes, not universal legal outcomes. Some preference uses may qualify for an exemption, while calling a tracking cookie “functional” does not change what it does. Strictly necessary cookies must be justified by the requested service, rather than the website owner’s convenience.
Functional cookies require consent where their use falls outside an applicable exemption or other permitted approach. The decision depends on the purpose, implementation and jurisdiction, rather than the category label in the banner.
Ask what the visitor requested, what information is stored, how long it is needed and whether it is reused. A necessary feature cannot provide a blanket exemption for an inseparable advertising purpose. Where additional purposes are not exempt, the storage or access must satisfy the relevant consent requirements.
EU cookie rules arise from the ePrivacy framework and national implementation. GDPR also applies where personal data is processed.
Under the exemption described by France’s CNIL, storage needed for an expressly requested service can avoid prior consent. Examples include authentication, shopping carts and certain interface preferences that are intrinsic to the expected service. This does not make every language, login or personalisation cookie exempt.
Personal-data processing remains subject to GDPR principles even when the storage is exempt. CNIL explains these distinctions in its guidance on cookies and trackers.
The ICO finalised its updated storage and access technologies guidance on 29 April 2026. Its appearance exception can cover uses whose sole purpose is to adapt or improve a service’s appearance or functionality.
Conditions include clear information, a simple and free way to object, and limits on related personal-data processing. Remembering a selected language or display preference may qualify. Choosing content or adverts from browsing behaviour or inferred interests does not fall within this exception.
The ICO’s explanation of the exceptions should guide the assessment of each use.
California’s CCPA, as amended by the CPRA, does not impose blanket prior consent for every functional cookie. Covered businesses must explain their personal-information practices and respect applicable rights.
If information is sold or shared for cross-context behavioural advertising, opt-out obligations may apply, including recognition of qualifying signals such as Global Privacy Control. A “functional” label does not remove those obligations. Other consent requirements can also apply in specific circumstances.
Disabling optional functional cookies usually affects convenience or particular features. The result depends on which cookies the website has placed in that category.
Preferences may reset: You may need to select your language, currency or theme again.
Optional features may be unavailable: A chat tool or embedded player may need permission before loading.
Core services may continue: Correctly classified necessary cookies can still support requested functions.
Rejecting an optional category in a banner differs from blocking every cookie in browser settings. Browser-wide blocking can also affect authentication and shopping carts. If optional refusal unexpectedly breaks checkout, the website should review its classification and dependencies.
Functional cookies can contain personal data or identifiers linked to a person. A simple value such as a language code may reveal little by itself, while an account-linked preference or chat identifier can relate to an identifiable visitor.
The surrounding processing matters too: who receives the identifier, what it connects to and whether it is reused. Neither “functional” nor “first-party” means anonymous or automatically exempt. Preference cookies should not store raw passwords. Authentication should use appropriately secured mechanisms, and the provider’s documentation should explain the cookie’s actual contents and purpose.
Review functional cookies as part of your normal website maintenance, particularly after adding plugins, media tools or customer-support services.
Identify: Use a cookie checker alongside provider documentation to find cookies and their sources.
Verify: Confirm every purpose, recipient and lifetime. A scanner’s suggested category is a starting point.
Classify: Separate necessary operations, optional preferences and additional tracking.
Explain: Keep the cookie policy specific about names, purposes, providers and durations.
Apply controls: Obtain cookie consent where required and support objections where an exception requires them.
Test: Check behaviour before a choice, after refusal and after withdrawal through the cookie preference centre.
Test both what the banner records and what the website actually stores or sends.
Functional cookies and preference cookies often describe the same purpose: remembering choices such as language, currency or display settings. Some providers use “functional” more broadly to include features such as live chat or embedded media. The names are not standardised legal categories. Classification should follow what each cookie actually does.
Functional cookies can be set on the website’s own domain or a third-party domain associated with an external service. A language preference might use a first-party cookie, while an embedded support tool may involve third-party cookies.
The domain alone does not determine whether consent is needed. The purpose and any additional use of the information also matter.
Functional cookies can use either storage period:
Session cookies usually expire when the browser session ends.
Persistent cookies have an expiry period and can remember preferences across visits.
“Functional” describes the purpose; “session” and “persistent” describe duration. A short-lived cookie is not automatically necessary, and a persistent cookie is not automatically a tracking cookie.
Their lifetime depends on the setting they support and how the website configures them. A temporary preference may last for one session, while a saved language choice may remain for future visits.
The duration should be proportionate to the purpose and disclosed in the cookie policy. Visitors can delete cookies earlier, and browser privacy settings may shorten their effective lifetime.
Login and shopping cart cookies support website functions, but cookies needed to maintain an authenticated session or preserve the current cart are commonly classified as strictly necessary.
Additional uses need a separate assessment. Keeping someone signed in during checkout does not automatically justify using the same identifier for profiling or advertising.
Deleting a cookie removes that browser-stored value, but it does not reliably update the website’s consent records or notify its service providers. It also does not automatically erase information already collected.
To withdraw consent, use the website’s cookie settings or preference centre. Deleting cookies can be an additional step, but it should not replace changing the recorded permission.
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