Every registered company in Nigeria owes Company Income Tax on its profit, yet a surprising number of founders only start thinking about it when a FIRS demand notice lands in their inbox, or worse, when a bank or investor asks for tax clearance and there's nothing to show. Company Income Tax, commonly shortened to CIT, is not optional, and understanding it properly from day one saves you penalties, stress, and a rushed scramble every filing season.
This guide breaks down exactly who pays CIT, how much, when, and how to stay compliant without hiring a full finance team.
What Company Income Tax Actually Is
CIT is a tax on the profit of companies registered in Nigeria, administered by the Federal Inland Revenue Service. It applies to limited liability companies, both private and public, registered with the Corporate Affairs Commission. It does not apply to sole proprietorships or partnerships, which are instead taxed under Personal Income Tax, collected by state revenue services like LIRS in Lagos.
This distinction matters more than most new founders realize. If you registered as a business name rather than a limited company, CIT does not apply to you directly, but Personal Income Tax on your business profit still does, and the reporting obligations are different.
Who Must Pay CIT
Any company incorporated in Nigeria, or any foreign company doing business in Nigeria and deriving income from within the country, must file and pay CIT annually, regardless of whether the company made a profit or a loss. Filing is mandatory even at zero profit, because the return itself is what keeps you in FIRS's good books and generates your tax clearance certificate.
There is meaningful relief for small companies. Under the Finance Act reforms, companies with annual turnover below ₦25 million are classified as small companies and are exempt from paying CIT entirely, though they must still file returns. Companies with turnover between ₦25 million and ₦100 million fall into the medium category. Companies above ₦100 million in turnover are classified as large.
How CIT Rates Work
The standard CIT rate for large companies is 30% of taxable profit. Medium companies pay a reduced rate of 20%. Small companies, as noted above, pay 0%, a meaningful incentive for early stage businesses to formalize and register rather than operate informally.
On top of CIT, companies must also account for Tertiary Education Tax, a separate 3% levy on assessable profit, which funds Nigeria's Tertiary Education Trust Fund and applies regardless of company size once you're above the small company threshold.
It's worth noting these thresholds and rates have shifted with recent Finance Act amendments, so always confirm the current figures on the FIRS portal or with a qualified tax adviser before filing, rather than relying on last year's numbers.
Calculating Taxable Profit
Taxable profit is not the same as the profit figure on your management accounts. FIRS starts from your accounting profit and then makes specific adjustments.
Certain expenses are disallowed for tax purposes even though they're legitimate business costs, such as depreciation on assets, which FIRS replaces with its own capital allowance calculation, and certain fines, penalties, or donations that don't meet FIRS's criteria for deductibility.
Other items get added back or deducted according to tax rules rather than accounting rules. This is precisely where many small businesses get into trouble, either overpaying because they didn't claim legitimate allowances, or underpaying because they didn't realize an expense wasn't deductible. A qualified accountant familiar with Nigerian tax law pays for itself here.
Filing Deadlines and Process
Companies must file their CIT return within six months of the end of their financial year. If your company's year runs January to December, your CIT return is due by 30 June the following year. New companies get an extended window, filing due within eighteen months of incorporation or six months after the first financial year end, whichever comes earlier.
Filing happens through the FIRS TaxPro Max platform, the mandatory online system for all federal tax filings in Nigeria. You'll need your Tax Identification Number, audited financial statements for companies above the small company threshold, and supporting schedules for any capital allowances or deductions claimed.
Late filing attracts penalties: a fixed sum plus a daily accumulating charge for continued non compliance, on top of interest on any unpaid tax. These penalties compound quickly and are entirely avoidable with basic calendar discipline.
Common Mistakes Nigerian Businesses Make With CIT
Confusing turnover with profit when checking the small company exemption. The ₦25 million threshold is based on turnover, your total revenue, not your net profit after expenses. A business with ₦30 million in sales and a thin margin still crosses into medium company status even if actual profit is small.
Filing late or not filing at all when there's no profit. Many founders assume a loss making year means no filing obligation. It doesn't. Filing is required regardless of profitability, and skipping it puts your tax clearance certificate at risk, which then blocks government contracts, some bank facilities, and certain regulatory approvals.
Not keeping proper records throughout the year. CIT filing becomes a nightmare when a business tries to reconstruct a year of transactions in the weeks before the deadline. This is exactly why a working chart of accounts and consistent bookkeeping habits, addressed elsewhere on this site, matter well beyond just satisfying curiosity about your numbers.
Ignoring capital allowances. Many small businesses miss out on legitimate deductions for equipment, vehicles, and other qualifying assets simply because nobody calculated the allowance correctly.
Practical Steps to Stay Compliant
Register for a Tax Identification Number immediately after CAC incorporation, don't wait until your first filing deadline approaches. Maintain monthly bookkeeping so your year end position is always current rather than reconstructed from memory. Engage an accountant or tax consultant familiar with current Finance Act provisions, since rates and thresholds change periodically. Set a calendar reminder well ahead of your six month filing deadline, and file even in loss making years to preserve your compliance status.
The Bottom Line
CIT compliance is not just about avoiding penalties. A clean tax filing history is often a prerequisite for government contracts, bank credit facilities, and investor due diligence. Businesses that treat tax compliance as a growth requirement rather than an annual chore tend to find every other part of formalizing their operations, from opening corporate bank accounts to applying for grants through BOI or NIRSAL, considerably smoother.
