Corporation Tax Services | CT600 Filed Fast

Sound familiar?

Filing your CT600 shouldn't be this stressful.

Most UK directors we speak to tell us the same story. If any of these sound familiar, you're in the right place.

Confused about what's actually deductible.

R&D relief, capital allowances, director expenses — the rules change every year and the wrong claim is an HMRC invitation.

Your accountant charges hourly for CT600.

A single return, priced by the hour, with no ceiling. We fix the fee before we start.

Filing deadline's tight.

CT600 is due 12 months after your accounting period end. Late = automatic penalty + interest. We turn it around within 3 weeks (or within a week for an extra £150).

What you get

Everything Included in Our Corporation Tax Service — Fixed Fee, No Surprises

Need only the Corporation Tax return because your year-end accounts are prepared elsewhere? That is exactly what this service covers. If you need your accounts prepared too, our micro-entity package includes both.

CT600 return prepared and reviewed
Corporation Tax calculation
Capital allowances claimed
HMRC online submission
Tax planning pointers included
Fixed fee — no hourly billing

What We Need to Prepare Your CT600

Your final year-end accounts (or the trial balance they were prepared from)
Details of assets bought or sold in the period, for capital allowances
Any director's loan account balances and dividends paid
HMRC agent authorisation, so we can file on your behalf

We prepare the tax computation and the iXBRL-tagged return, and you approve it before we submit.

CT600 Corporation Tax return prepared and submitted to HMRC. We calculate your tax, claim capital allowances and R&D relief where applicable, and file on time — every time. Ideal if your year-end accounts are produced elsewhere but you need a chartered accountant to handle the tax return.

Traditional accountant

Hourly billing and changing quotes
Weeks of emails and chasing
Office meetings and paperwork
Limited visibility of progress
Sign-off may vary

SmartFiling

Fixed fee agreed upfront
Filed within 3 weeks of receiving your records
100% online and paper-free
Regular email updates
Every filing reviewed by an ICAEW Chartered Accountant

Our turnaround promise.

We file within 3 weeks of receiving your complete records. Need it sooner? Express turnaround within a week is available for an additional £150, subject to availability.

Ready to file — or still weighing it up?

Get a fixed-fee quote in under a minute. We reply within one working day with everything included, no obligation.

Get my quote

Fixed fee

Fixed fee · No surprises

ICAEW Chartered Accountant sign-off
3 weeks turnaround
Fully online
No phone call needed

Get a free quote

Reply within one working day · no obligation

Service you need* Full name* Email* Phone Nature of business Company name Companies House number Annual turnover Accounting year-end (if known) Next filing deadline (if known) Tell us about your business and what you need I agree to be contacted about my enquiry and have read the privacy policy.*

Fixed quote by email within one working day · No obligation. We only use your details to reply to this enquiry.

✓ UK Chartered Accountants ✓ Fixed fee ✓ 100% online

Simple by design

How Our Corporation Tax Accountant Service (CT600) Works

01
Get your fixed quote

Tell us about your situation. We reply within one working day with a fixed fee, and exactly what's included — no hidden extras.
02
Share your records

Upload securely through our portal. Bank statements, invoices, payroll — all digital. We tell you exactly what we need.
03
Filed in 3 weeks

Your ICAEW Chartered Accountant prepares the filing, you approve in plain English, we submit to HMRC and Companies House.

Get Started See the full process

Common questions

FAQs About Our Corporation Tax Service

Still not sure? Email a chartered accountant directly — we reply within one working day.

Can you file my CT600 if another accountant prepared my accounts?

Yes. Send us the final accounts and we prepare the tax computation and CT600, then file it with HMRC once you approve.

Is filing the return the same as paying the tax?

No. The CT600 is due 12 months after the end of your accounting period, but Corporation Tax for most small companies is payable 9 months and 1 day after it. We tell you the amount and payment date; your company pays HMRC directly.

What if my first accounting period is longer than 12 months?

An accounting period for Corporation Tax can't exceed 12 months, so a longer first period of account needs two CT600 returns. We prepare both.

What are the penalties for a late CT600?

For returns with a filing date on or after 1 April 2026, HMRC charges £200 if the return is up to 3 months late and £400 if it is later, with higher amounts for repeated failures. Tax-related penalties of 10% or 20% of unpaid tax can follow for very late returns.

Are the accounts attached to my CT600?

Yes. The return is filed with your accounts and tax computation in iXBRL format — we handle the tagging.

Also available

Other fixed-fee services you might need.

Micro-Entity Accounts Filing

FRS 105 accounts prepared and filed with Companies House and HMRC. Accounts, CT600, and all filings included in one price.

From £299

See Micro-Entity Accounts Filing

Bookkeeping

Monthly or quarterly bookkeeping that keeps your records HMRC-ready year-round and makes accounts filing simpler every time.

Flexible plans available

See Bookkeeping

MTD VAT Filing

Making Tax Digital-compliant VAT returns prepared and submitted. We stay current with HMRC changes — you don't have to.

From £199 a quarter

See MTD VAT Filing

Ready when you are

Get Your Corporation Tax Filed — Properly.

Fixed fee · No surprises · 3 weeks turnaround · ICAEW Chartered Accountants.

Get a Quote See all pricing

UK Chartered Accountants · ICAEW-regulated

100% Online

Fixed fees from £149

PII insured