The rule of mitigation requires a claimant to take steps to minimise its loss and to avoid taking unreasonable steps that increase its loss. An injured party cannot recover damages for any loss (whether caused by a breach of contract or breach of duty) which could have been avoided by taking reasonable steps. The claimant is said to have a "duty to mitigate". However, this is not a duty enforceable by anyone, rather it is a recognition that if the claimant fails to do so its damages recovery will be affected by that failure.

For further guidance, see Practice note, Damages in tort: an overview and Practice note, Damages for breach of contract: an overview.