Canada's Income Tax Act has swelled from pamphlet to 3,000-page burden

The federal Income Tax Act has ballooned from a 14-page document in 1917 to a sprawling text of more than 3,000 pages and roughly one million words. Business leaders and tax experts say the system's immense complexity imposes billions of dollars in compliance costs on companies and households while undermining Canada's investment climate. The original Income War Tax Act was introduced to help finance the First World War and was comparatively simple. Its modern descendant, described by one lawyer as a "Frankenstein's monster," is a dense repository of credits, deductions and rules accumulated over more than a century.

Steve Suarez, a partner at the law firm Borden Ladner Gervais, said the system keeps having new rules bolted on while nothing is ever removed. "As a result, he said, companies are spending more and more on lawyers, accountants and internal tax staff simply to comply," Suarez said. He added that small businesses are left largely adrift and households face higher bills. "As a guy with 35 years of experience invested in the current system, I've got every incentive to keep the complexity," he said. "But as a Canadian and as a father, I know we've got to do better than this."

Research into the physical growth of the tax code illustrates the problem. François Vaillancourt, a professor emeritus of economics at the Université de Montréal, collaborated on a study that measured the area occupied by the Income Tax Act and its regulations between 1971 and 2014. The researchers found the physical size increased by 355 per cent over that period. The number of special tax treatments, known as tax expenditures, and the length of taxpayer guides also climbed significantly. Vaillancourt said the three measurements were highly correlated, all pointing toward a much more complex system.

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"Did it go up by 20 per cent or 24 per cent? Can't be that precise," Vaillancourt said. "But it obviously went up." He noted that while software and electronic filing have made it easier for individuals to handle the complexity, small-business owners gain much less relief from technology. They still require expertise to determine which rules apply and which exemptions are available. Vows to simplify the tax code have been a recurring theme in Ottawa for decades, echoing across royal commissions and parliamentary committees.

Those investigations often return to similar recommendations: broaden the tax base, reduce special preferences and make the system cheaper to administer. In the last federal election, former Bank of Canada governor Mark Carney made tax simplification part of his platform, promising an expert review of the corporate tax system. The Canadian Tax Foundation in Toronto holds copies that trace this evolution, from the slim 1917 act to the 1944 version and the latest bilingual edition, which is about the size and weight of a breadbox. Each edition marks a key moment, reflecting the country's changing social priorities and economic anxieties. The original copies arose during global wars, which permanently transformed how Ottawa collected revenue. The most recent edition was published in August 2026, just days before a high-stakes round of trade talks between Canada and the United States collapsed. Politicians have often argued they had more immediate problems to solve than the elegance of the tax code, even as its complexity continued to accumulate.

With files from The Globe and Mail