encodeURI vs encodeURIComponent?

This page uses encodeURIComponent so &, =, and spaces become percent sequences. That is what query values need.

On decode, + is treated as a space, which matches form bodies.

Build campaign URLs on the UTM generator. Encode a single value here.

decodeURIComponent throws; the tool shows that instead of crashing.

Runs in your browser · Last updated 4 September 2026

URL Encode Decode

encodeURIComponent and decode percent-encoded query text locally. No request is made.

Input

encodeURIComponent

https%3A%2F%2Fexample.com%2Fq%3Fa%3D1%20%26%20b%3Dtwo

Decoded (if the box is already encoded)

https://example.com/q?a=1 & b=two

The sample URL has a space and an ampersand. encodeURIComponent turns them into %20 and %26 so a query parser does not split the value.

encodeURI vs encodeURIComponent?: This page uses encodeURIComponent so &, =, and spaces become percent sequences. That is what query values need.
Uploaded?: No.
Plus signs?: On decode, + is treated as a space, which matches form bodies.
UTM?: Build campaign URLs on the UTM generator. Encode a single value here.
Invalid %?: decodeURIComponent throws; the tool shows that instead of crashing.