How is fault apportioned when both the plaintiff and defendant are partly to blame?

What the Law Says

Canadian tort law applies contributory negligence rules to reduce a plaintiff’s recovery in proportion to their own blameworthiness. These rules are set out in provincial legislation, which uniformly permits courts to assign fault percentages to all parties involved.

Each province has its own Contributory Negligence Act (or equivalent), which allows courts to divide liability fairly when the plaintiff’s own negligence contributed to the harm. The core principle is that damages are reduced by the percentage of fault attributed to the plaintiff.

The legislation does not prescribe fixed formulas — instead, judges assess the relative importance of each party’s conduct in causing the loss, considering factors like foreseeability, seriousness of breach, and opportunity to avoid harm.

What Courts Have Said

The Supreme Court of Canada has affirmed that apportionment of liability is a factual exercise grounded in fairness and proportionality — especially where statutory frameworks permit flexible, case-specific assessments.

What to Do

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