---
name: Address autocomplete
slug: address-autocomplete
category: pattern
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-25T00:00:00.000Z
definition: Replacing a set of address fields with one lookup that suggests full
  addresses after a few characters and fills the rest on selection.
aliases:
  - name: address lookup
    source: govuk
  - name: postcode lookup
    source: govuk
  - name: address finder
    source: community
  - name: autofill address
    source: community
tags:
  - forms
  - search
relations:
  contrastWith:
    - input-purpose
    - autofill
  variantOf: []
  partOf: []
  seeAlso:
    - typeahead
implementations: []
sources:
  - title: "GOV.UK Design System: Addresses"
    url: https://design-system.service.gov.uk/patterns/addresses/
demo: inline
exhibit: false
useWhen: typing a postcode fills in the whole address
---

An address is the worst-shaped thing a form ever asks for. It has a different number of
parts in every country, the parts are named differently, and half of them are ambiguous to
the person who lives there. Address autocomplete replaces the interrogation with a single
lookup: type a few characters of a street or a postcode, pick a real address out of the
suggestions, and the structured fields fill themselves in. Seven decisions become one, and
the one that remains is the only one the reader is actually qualified to make.

The machinery is a [combobox](/combobox) over an address database, which is worth saying
plainly because it means the pattern inherits a solved accessibility problem rather than a
new one: a text input, a listbox of suggestions, arrow keys, an active option, and a chosen
value announced when it lands. [Mention autocomplete](/mention-autocomplete) is the same
machinery aimed at people instead of places, and the difference between them is entirely in
what the query is matched against. What address autocomplete adds on top is the fan-out:
one selection writes several fields, so the reader has to be able to see what was written
and correct it.

That last part is where implementations fail. A lookup that swallows the address into an
opaque token leaves anyone with a flat number, a new build, a farm, or a business park with
no way to finish, because the database is always a little behind the world. Keep the
structured fields on screen after the fill, keep them editable, and keep a plain "enter it
manually" path within reach rather than behind an apology. The [GOV.UK Design
System](https://design-system.service.gov.uk/patterns/addresses/) is unusually blunt about
this: a lookup is an optimisation over the manual fields, not a replacement for them.

Two details buy most of the remaining quality. Wait until the query has enough in it to be
worth answering, so one character does not return a thousand streets, and say what the field
wants before anything has been typed. And reserve the room the suggestion list will take, so
opening it never shoves the rest of the form down the page under someone who is
mid-sentence.