If your business operates at a loss over a fiscal year, you have a non-capital loss. For example, if you have $70,000 in revenue and $100,000 in expenses in a tax year, you have a non-capital business loss of $30,000. You can apply this type of loss against all types of income. To continue with the above example, you may use the $30,000 business loss to reduce employment or business income on your tax return. For instance, if you have $50,000 in income, you can use the loss to reduce your income to $20,000.You can claim your non-capital business loss on your current return, but if you don’t have enough income to claim the loss against, you may want to carry it back to a previous year. You can carry non-capital business losses back three years. For example, if you have a business loss for tax year 2016, you can opt to apply that loss to income from 2013, 2014, or 2015. To carry back your business loss, you should fill out Form T1A and submit it with your current year’s tax return.Business losses can be a huge disappointment, but you can apply them to your income from the three previous years. That lowers your income on paper for those years and retroactively reduces your tax bill. If you don’t have old income to claim the loss against, you are in luck; you can also carry forward business losses for 20 years and claim them against future income.