Wave Accounting and CT600 Filing

Wave is a popular free accounting software used by many small UK businesses. While Wave handles your day-to-day bookkeeping, you'll need specialist software like TinyTax to file your CT600 corporation tax return.

Understanding Wave's Capabilities

Wave is excellent for:

• Invoice creation and tracking
• Expense recording
• Bank connection and reconciliation
• Basic financial reports

• File CT600 returns to HMRC
• Generate iXBRL accounts for Companies House
• Calculate UK corporation tax
• Handle capital allowances

Exporting from Wave

Profit and Loss Report

1. Log into Wave at waveapps.com
2. Navigate to Reports > Profit & Loss
3. Set the date range to match your accounting period
4. Click Export to download as CSV or PDF

Balance Sheet

1. Go to Reports > Balance Sheet
2. Set the date to your period end
3. Export the report

Account Transactions

For detailed records:

1. Navigate to Accounting > Transactions
2. Filter by date range
3. Export transaction list

Preparing Your Year End in Wave

Before exporting your figures, ensure Wave is up to date:

Bank Reconciliation

• Connect your bank feeds (Wave supports this for many UK banks)
• Match all downloaded transactions
• Clear any unmatched items

Invoice Management

• Send all outstanding invoices
• Mark paid invoices as received
• Write off any bad debts

Expense Recording

• Ensure all expenses are entered
• Attach receipts where possible
• Categorise expenses correctly

Wave Categories to CT600 Boxes

Manual Entry to TinyTax

Since Wave doesn't have a direct export format for trial balances, you can manually enter your figures:

1. Open your Wave Profit & Loss report
2. Start CT600 filing in TinyTax
3. Enter your turnover figure (Box 145)
4. Enter your total expenses
5. Add any other income or deductions

Wave's Limitations for UK Tax

Be aware of these limitations:

No UK Tax Calculations

Wave doesn't calculate UK corporation tax. It was designed primarily for US and Canadian markets.

Limited Report Formats

Export options are basic. You may need to reformat data for tax filing.

No Companies House Filing

Wave cannot generate the iXBRL accounts required for Companies House.

Supplementing Wave with TinyTax

The ideal workflow:

Wave for: Day-to-day bookkeeping, invoicing, expense tracking

TinyTax for: CT600 filing, tax calculations, Companies House accounts

Year-End Checklist for Wave Users

Before filing your CT600:

• All bank transactions reconciled
• Invoices marked as paid/unpaid correctly
• Expenses properly categorised
• Profit & Loss report matches your records
• Balance Sheet reviewed for accuracy

Common Issues

Incomplete Bank Feeds

Wave's UK bank connections can be limited. Ensure you've manually entered any transactions not captured.

Currency Conversions

If you have foreign currency transactions, ensure Wave has converted them correctly.

VAT Treatment

Wave handles VAT but ensure your reports show the correct net figures for CT600.

Filing Your CT600

With your Wave data prepared:

1. Export your Profit & Loss from Wave
2. Start your CT600 in TinyTax
3. Enter your income and expense figures
4. Review and add any tax adjustments
5. Submit to HMRC and Companies House

Key Takeaways

• Wave is great for bookkeeping but doesn't file CT600
• Export Profit & Loss and Balance Sheet at year end
• Enter figures manually into TinyTax
• TinyTax handles tax calculations and filing
• Complete bank reconciliation before exporting