Is it better to leave a charity a fixed dollar amount or a percentage of the estate residue in Ontario?

There's no universally "better" choice — it depends on what you're trying to achieve, and each approach carries a different trade-off. A fixed dollar amount gives the charity certainty about what they'll receive, but if your estate turns out to be worth significantly less than expected by the time you die, due to declining asset values, unexpected expenses, or debts, that fixed amount could end up being disproportionately large relative to what's left for your other beneficiaries. If the estate has grown substantially instead, a fixed amount could end up disproportionately small relative to what you might have wanted the charity to receive.

A percentage of the residue automatically scales with the actual size of your estate at death, which many people find better reflects their real intention of giving the charity a meaningful share, whatever that ends up being, without needing to update the will every time asset values shift significantly.

Many people use a combination, a modest fixed gift plus a percentage of residue, or several percentage gifts split among family and charity, to balance certainty and flexibility. Discuss your specific goals and estate composition with a lawyer to decide which structure fits your situation best.