Corporation Tax is the tax your limited company pays on its profits. If your company is registered at Companies House, you have a legal obligation to report those profits to HMRC and pay the tax due.
This is done through a CT600 — the Corporation Tax return. It's separate from your company accounts but directly linked to them.
Your company accounts (filed with Companies House) show your income, expenses, and profit for the year. The CT600 takes those figures and adjusts them for tax purposes — adding back disallowable expenses, applying capital allowances, and calculating the actual tax you owe.
In short: your accounts tell the story, your CT600 calculates the bill.
Your CT600 must be submitted to HMRC within 12 months of your company's accounting period end.
Corporation Tax payment is due earlier — 9 months and 1 day after your accounting period ends.
Most companies think about Corporation Tax once a year — usually when the deadline is close. That's when mistakes happen, reliefs get missed, and you end up paying more than you should.We work differently. We start early, plan ahead, and make sure your tax position is optimised before the year ends and not after.
We don't wait until your deadline when everything turns into firefighting mode. We review your position throughout the year so you can make decisions that reduce your tax bill legally and strategically.
We prepare your Corporation Tax return and file it with HMRC. We calculate your actual tax liability — adjusting for capital allowances, disallowable expenses, and reliefs you're entitled to. Every figure checked, every adjustment made, every deadline met.
Made a loss? That's not wasted — it's an asset. We'll help you carry it forward to offset future profits, carry it back to reclaim tax you've already paid, or surrender it to group companies. Whichever route saves you the most. Particularly valuable for startups expecting to become profitable.
This service is for UK limited companies — whether you're a solo founder, a small team, or scaling fast.
Upload your financials or connect your accounting software (Xero, QuickBooks, FreeAgent). We'll pull what we need.
We build your tax computation, check for reliefs, and make sure nothing is missed. Every return is reviewed by an ACCA-qualified accountant.
You get a clear summary of your tax position before we submit. No surprises. Then we file with HMRC and confirm everything's done.
GenTax was founded by Mohamed Sayedi — ACCA qualified, 5 years in compliance, 5 years in finance technology including 3 years at EY. Built on experience and backed by technology.
We're not a faceless filing factory. We're a small team that understands what founders actually need: clarity, reliability, and someone who gets the numbers right the first time.
