For many Americans, the days leading up to tax day are some of the most dreaded on the calendar. Over the past several weeks, Americans have spent many frustrating hours poring over W-2’s and Form 1040’s as they prepare their tax returns. According to the Internal Revenue Service, Americans collectively spend roughly 6.6 billion hours a year filling out tax forms for Uncle Sam.

In case the burdensome task of filing taxes isn’t cause enough for celebration, this week also marks “Tax Freedom Day” as calculated by the Tax Foundation. That’s the date on which Americans have earned enough income to pay their tax bills for all levels of government in 2016.

By this Saturday, April 24—114 days into the year—Americans will have finally earned the estimated $5 trillion to pay their federal, state, and local government’s tabs for 2016. That means Monday represents the first day of the year when Americans will be earning income for themselves rather than the government.

Don’t queue the confetti just yet—if you include federal borrowing (which represents future taxes owed), Tax Freedom Day gets pushed back 16 days later to May 10.

The amount forked over to government isn’t the only cost of taxes. Taxpayers also incur additional “hidden” compliance costs during the tax preparation process. These can be divided into two broad categories: accounting costs and economic costs.

Accounting costs include the opportunity cost of taxpayers’ time and effort, as well as any expenses paid to tax professionals or used to purchase tax preparation software. As the complexity of the tax code has increased, so too have the accounting costs. In 2013 the Mercatus Center analyzed previous studies that quantified these costs, finding that the estimated annual total ranges from $67 billion to $378 billion.

The economic costs of tax compliance fall into two subcategories: Lobbying expenditures and deadweight loss.

Lobbying expenditures are costs paid by firms in order to protect and/or gain tax advantages by petitioning federal, state and local governments. Deadweight loss is a term used by economists to reflect the costs borne when economic decision making—namely how individuals choose to spend and save- is distorted as a result of tax implications.

It can be thought of in terms of all the foregone economic transactions that would have occurred in the absence of taxes. Although it is more difficult to calculate, the Mercatus report estimates that the cost of this lost economic growth ranges from $148 billion to $609 billion.

Combined, the accounting and economic costs of compliance increase taxpayers’ burden by up to $1 trillion, an additional 20 percent on top of what Americans will be paying out to the Treasury this week. This is a real cost that undermines economic growth, and lawmakers should take steps to mitigate the problem by moving towards a simpler, more transparent system based on a consumption tax.

A consumption-based tax code would dramatically reduce complexity and therefore lower accounting costs. It would also minimize the economic distortions created by our tax system, and would thus reduce deadweight loss.

Tax reform that established a consumption tax would boost the economy and increase opportunity for all Americans. Congress should be laying the groundwork for tax reform now.