What Is the Difference Between Trespass to Chattels and Conversion?
With the Tort of Trespass to Chattels the Interference or Damage to the Chattel Occurs Without Removing the Chattel From the Rightful Owner or Person With Rightful Possession. With Conversion or Detinue a Loss of Possession of the Chattel Occurs.
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The tort of trespass to chattels involves wrongful interference with chattels whereas the legal definition of chattels involves personal property objects that are unattached to land; and accordingly, a chattel may include items such as automobiles, aircraft, watercraft, household furnishings, artwork, moveable machinery, goods or stock of commercial inventory, pets and livestock, among various other belongings.
Trespass to chattels is similar to conversion and detinue whereas all three relate to wrongful interference with a chattel; however, the distinguishing nuance with trespass to chattels is that the object remains in possession or control of the owner or person with rightful possession which differs from conversion and detinue where the owner or person with rightful possession is deprived of possession. Perhaps the easiest way to explain the difference is to use the criminal law term in that conversion or detinue may arise from theft (criminal law term) of the objecdt, being interference by removing the chattel from the possession of the rightful owner or person with right of possession and trespass to chattels may arise from vandalism (criminal law term) being interference without removal of the chattel.
The elements necessary to give rise to the tort of trespass to chattels were well articulated in Ontario Consumers Home Services v. Enercare Inc., 2014 ONSC 4154 where it was stated:
 In Hudson’s Bay Company v. White,  O.J. No. 307 (Ont.Gen.Div.) Lederman J. at para. 8 referenced the criteria necessary for trespass to chattels:
In Clerk and Lindsell on Torts, 17th ed. (London: Sweet and Maxwell, 1995), at p. 705, the authors define trespass to chattels, or “trespass to goods”, as being concerned with “the direct, immediate interference with the plaintiff’s possession of a chattel”. Halsbury’s offers a similar definition at Vol. 45, para. 1491: “Trespass to goods is an unlawful disturbance of the possession of goods by seizure or removal, or by a direct act causing damage to the goods”.
Where chattels, such as an automobile as a personal belonging, or other thing, is harmed per the law of trespass to chattels, a lawsuit may make claim for the resulting actual loss suffered, meaning the devaluation of the object as a result of the harm to the object. Furthermore, depending on the circumstances, especially where the trespass was troublesome and emotionally disruptive, general damages may be appropriate; and additionally, where the trespass was intentional or egregiously malicious, punitive damages may be applicable.
The tort of trespass to chattels is found within the family of interference torts which include, among others, the torts of conversion and detinue. The key difference with the tort of trespass to chattels and the tort of conversion or the tort of detinue, is that with trespass to chattels, the chattels, meaning goods or personal belongings, remain with the rightful owner or person with rightful possession.
The torts of trespass to chattels, conversion, and detinue, are often confused whereas the lines between each can, and often do, cross depending on the circumstances. Legal practitioners and scholars could spend hours discussing the various interplay between these various torts, among other torts. As always, these pages provide merely a beginning.