Translation guide
An add-on is something extra that is added to an existing thing to enhance or supplement it. In Japanese, the translation depends on whether it's a physical attachment, a software extension, an optional extra, or an additional item.
A software module that adds features to a program or browser.
An additional item or feature that can be purchased or added to a base product.
Commonly used for optional extras in cars, appliances, or services.
A sunroof is available as an add-on for this car.
Explicitly 'additional option', used when emphasizing it's an extra choice.
Would you like to add insurance as an add-on?
Accessory or attachment, often for physical products like cameras or appliances.
A piece that can be attached to a device or tool to add functionality.
Something extra added to a set or collection, not necessarily physical.
Directly translating 'add-on' as 付け加え (tsukekuwae) or 追加物 (tsuikabutsu) is unnatural. Use the appropriate loanword or context-specific term.
Literally 'extension function', commonly used for browser extensions and software plugins.
I installed a Chrome extension.
このプラグインで動画編集が簡単になります。
This plugin makes video editing easier.
この掃除機の付属品は別売りです。
The add-ons for this vacuum cleaner are sold separately.
カメラの付属品がたくさんあります。
There are many add-ons for the camera.
This magazine comes with an add-on (free gift).