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Getting Started with the Dashboard

Learn how to navigate your 0T TinyTax dashboard. Understand status icons, start filings, return to drafts, and use the company details drawer.

What Can You File?

See every company type, filing type, and tax feature 0T TinyTax supports. Check whether your company is eligible.

Saving Your Work and Drafts

0T TinyTax saves automatically - no save button needed. Learn how your data is preserved and how to return to unfinished filings.

What Company Sizes Does TinyTax Support?

What You Can File

How to File Your First CT600

Step-by-step guide to filing your first CT600 corporation tax return with 0T TinyTax. Covers company type selection, P&L entry, balance sheet, and HMRC submission.

How to File a Corporation Tax Return

How to file your corp tax return (CT600) with HMRC. Step-by-step guide for UK limited companies.

What Happens After You Submit

What to expect after submitting your CT600 and accounts via 0T TinyTax. HMRC timelines, confirmation emails, and troubleshooting.

CT600 Filing Checklist

Complete CT600 checklist for UK companies. Everything you need to gather before filing your corporation tax return. Avoid mistakes and delays.

How to Pay Corporation Tax

Step-by-step guide to paying your corporation tax to HMRC. Payment methods, deadlines, and what happens if you pay late.

Associated Companies and Marginal Relief

How associated companies affect your corporation tax thresholds and marginal relief calculation in 0T TinyTax.

CT600 Amendments

Need to correct your CT600 after filing? Learn when you can amend, the 72-hour wait, and how to do it in 0T TinyTax.

Filing a Late CT600

Yes, you can file a late CT600 with 0T TinyTax. Here's what penalties apply and how to submit.

Mark a Prior CT600 as Filed Elsewhere

Mark previous CT600 periods as filed elsewhere if you used an accountant or other software. Unblock current filings without refiling old periods.

Set Up Your Government Gateway

How to set up Government Gateway for your UK company. Step-by-step guide to creating your HMRC online account and enrolling for Corporation Tax services.

VAT, PAYE, and CS01

0T TinyTax does not currently support VAT, PAYE, or confirmation statements. Here's what we do support and where to file these.

Common Expense Categories

Where do your business costs go on the P&L? A guide to the four expense categories in 0T TinyTax's micro-entity format.

Property Company Accounting

How to file a CT600 for a property company with 0T TinyTax. Covers rental income, property expenses, and Box 170.

Capital Allowances and AIA

Claim tax relief on business equipment with Annual Investment Allowance (AIA). Learn what qualifies, limits, and how to enter capital allowances in 0T TinyTax.

Capital Gains and Disposals

How to report chargeable gains on your CT600. Covers Box 210, supported company types, and workarounds in 0T TinyTax.

Director's Loans and the CT600A

What is a director's loan account, and when do you need the CT600A? Covers DLA, S455 tax, and what 0T TinyTax supports.

Extended Accounting Periods

Accounting period over 12 months? Learn why you need two CT600 returns, how to split profits correctly, and which deadlines apply.

Filing for Charities and Community Benefit Societies

Can you use 0T TinyTax for a charity or community benefit society? See which organisation types are supported.

How to Change Your Accounting Period

How to change your company's accounting period. Understand the rules for shortening or extending your financial year with Companies House.

How Losses Brought Forward Work

Use previous year losses to reduce corporation tax. Learn how brought forward losses work, where to enter them, and how they offset profits.

CIS Deductions

How Construction Industry Scheme (CIS) deductions work on the CT600. Covers Box 515 and current limitations in 0T TinyTax.

Exchange Rate Differences

Where to enter exchange rate gains and losses on your CT600 in 0T TinyTax. Covers FRS 105 treatment.

Prepare for Software-Only Filing

How to prepare your company for mandatory software-only filing of CT600 returns and company accounts. Timeline and checklist included.

Switch from Companies House WebFiling

Guide to switching from Companies House WebFiling to commercial software before the April 2027 deadline.

Switch from HMRC's CT600 Service

Step-by-step guide to switching from HMRC's free CT600 filing service to commercial software before the March 2026 deadline.

Download Your CT600 History from HMRC

Step-by-step guide to downloading your CT600 filing history from HMRC before the service closes in March 2026. Don't lose access to your records.

Filing for CICs and CLGs

File CT600 for Community Interest Companies (CICs) and Companies Limited by Guarantee (CLGs). Learn what 0T TinyTax supports for these special company types.

Government Gateway and Corporation Tax Enrolment

How to Amend a CT600

How to file an amended CT600 when HMRC already has your return. Fix errors in figures, correct information, or respond to HMRC queries.

How to File a Dormant CT600

File your dormant company CT600 with 0T TinyTax. Learn what counts as dormant, which fields to complete, and the difference between HMRC and Companies House dormancy.

Loss Carry-Back Claims

Understanding Your Tax Calculation

Understand how corporation tax is calculated from your accounting profit. Explains key CT600 boxes, disallowable expenses, capital allowances, and tax rates.

Unsupported Tax Features

0T TinyTax is designed for straightforward filings. Learn what advanced CT600 features aren't supported and how to work around limitations using existing fields.

Your First CT600 After Dormancy

Your first CT600 after dormancy covers a different period than you expect. Learn how CT600 periods work when transitioning from dormant to trading.

Troubleshooting CT600 Errors

Fix common 0T TinyTax errors including HMRC Error 3001, authentication failures, invalid UTR, and Companies House auth code issues.

Fix CT600 Submission Errors

Fix CT600 submission errors quickly. Common error codes explained with step-by-step solutions for HMRC rejection issues.

Fix CT600 Authentication Errors

CT600 authentication failed when filing? Learn why HMRC rejects your credentials and how to fix authentication errors step by step.

Fix Government Gateway Login Errors

Can't log into Government Gateway? Fix common login errors including forgotten User ID, locked accounts, and authentication failures.

HMRC Error 1046: Authentication Failure Fix

Getting HMRC Error 1046 when filing your CT600? This guide explains why authentication fails and how to fix your Government Gateway credentials.

HMRC Error 1608: Invalid UTR Fix

Getting HMRC Error 1608 when filing CT600? This guide explains why your UTR is being rejected and how to fix the invalid UTR error.

HMRC Error 3001: Business Logic Failure Fix

Getting HMRC Error 3001 when filing CT600? Learn what causes this iXBRL validation error and how to resolve business logic failures.

CT600 Not Showing on HMRC Website

Troubleshooting HMRC Submission Errors

Pricing and Plans

Which 0T TinyTax plan is right for you? Compare Solo and Portfolio plans, billing, and what's included.

Billing, Pricing, and Cancellation

How billing works on 0T TinyTax. Pay-per-filing pricing, refund policy, and cancellation.

Export Your Xero Trial Balance

Step-by-step guide to exporting your trial balance from Xero. Get your accounts ready for CT600 filing with 0T TinyTax.

How to Import Your Trial Balance

How to import your trial balance into CT600 software. Speed up corporation tax filing by importing from Xero, QuickBooks, or CSV files.

Xero to CT600: Import Your Trial Balance

How to export your trial balance from Xero and import it into CT600 software. Step-by-step guide for faster corporation tax filing.

QuickBooks to CT600 Guide

How to export your trial balance from QuickBooks and import it into CT600 software. Step-by-step guide for UK corporation tax filing.

FreeAgent Category Mapping

How FreeAgent categories map to 0T TinyTax's P&L fields. Includes trial balance import instructions.

FreeAgent to CT600 Guide

How to use FreeAgent accounts for your CT600 filing. Export your trial balance and complete your corporation tax return with 0T TinyTax.

Sage to CT600 Guide

How to use Sage accounts for CT600 filing. Export your trial balance from Sage 50 or Sage Business Cloud and file with 0T TinyTax.

Wave to CT600 Guide

How to use Wave Accounting for CT600 filing. Export your financial data from Wave and file your corporation tax return with 0T TinyTax.

CT600 from Spreadsheets

How to file CT600 when you use Excel or Google Sheets for bookkeeping. Prepare your spreadsheet accounts for corporation tax filing.

Small Company Accounts (FRS 102 Section 1A)

How 0T TinyTax automatically detects whether your company needs micro-entity or small company accounts, and what's different.

Micro-Entity vs Small Company Accounts

When does 0T TinyTax use micro-entity (FRS 105) vs small company (FRS 102 Section 1A) accounts? Covers thresholds and auto-detection.

What Is a Confirmation Statement?

What is a confirmation statement? When it's due, what it contains, and how to file. Your guide to this annual Companies House requirement.

How to Strike Off Your Company

How to close your limited company by striking off. Understand the process, requirements, and alternatives to voluntary dissolution.

Companies House Auth Code

Find your Companies House Authentication Code for filing accounts. Learn where to locate it, how to request a new one, and fix common auth code errors.

Filing LLP Accounts with Companies House

How to Amend Companies House Accounts

How to File Final Returns When Your Company Has Ceased Trading

Step-by-step guide to filing your final CT600 and accounts before dissolving your limited company. Learn how to set custom period dates for a shortened final return.

How do I connect Xero to TinyTax?

How to Edit or Change Your Accounting Period Dates

How to enter custom accounting period dates when your CT603 shows different dates from the dropdown.