Accounting and invoicing for interim managers
Leadership on demand, crisis management and project leadership: interim managers work one to twelve months for a client and bill day rates, supplements and expenses. Saldiqo creates the monthly invoice from days, records travel costs and reminds on long payment terms.
What comes up for interim managers
High day rates, few clients
An assignment brings a lot of turnover with one client. Payment defaults hurt.
Expenses and accommodation
Flat at the place of work, travel and meals are often reimbursed.
Gaps between assignments
Between two assignments no revenue arises. An overview of costs and reserves helps.
How Saldiqo helps
- Monthly invoice from daysRecord days, create the invoice.
- Re-invoice expensesReceipts as expenses, line with the receipt.
- RemindersKeep open invoices in view.
- Overview of income and expensesA report per year or assignment.
Typical invoice lines
Examples that often appear on invoices in this industry. You set the prices yourself.
- Interim management, 21 days in November
- Supplement for travel days
- Accommodation as per receipt
- Travel costs as per receipt
- Standby outside assignment days
- Final report and handover
Tax and invoicing in the UK
What applies to invoices in the UK, in short. As of October 2026.
- VAT
- Standard rate 20 %, reduced rate 5 % and zero rate 0 %. Saldiqo calculates each invoice line with the rate you pick.
- VAT registration
- You must register once your taxable turnover passes £90,000 over any 12 months, or you expect to pass it within the next 30 days. You can deregister below £88,000. Until you are registered, your invoices show no VAT, and Saldiqo adds up your 12-month turnover for you.
- What goes on an invoice
- If you are VAT registered: your VAT number, the tax point, unit prices and the VAT total in pounds. A limited company shows its registered name on every invoice, and its company number, registered office and part of the UK on letters, order forms and the website.
- E-invoicing
- There is no mandate today. From April 2029 e-invoicing is planned for all B2B and B2G sales that carry VAT, through Peppol. The exact date and standard are not yet in law, and the government’s roadmap follows with the Budget on 28 October 2026.
- VAT returns
- VAT returns go to HMRC through Making Tax Digital, usually quarterly, due one month and seven days after the period. Saldiqo shows sales and VAT per rate and exports CSV. It does not submit to HMRC, and for Making Tax Digital you need software recognised by HMRC.
- Record keeping
- Keep VAT records for 6 years.
- Late payment
- Statutory interest on late business payments is the Bank Rate (3.75 % in the second half of 2026) plus 8 points, so 11.75 %. On top comes fixed compensation of £40, £70 or £100, depending on the amount owed (under £1,000, from £1,000, from £10,000). Consumers have no statutory interest.
- Getting paid
- Your sort code and account number are on every invoice. Customers pay by Faster Payments or Bacs, and banks check the account name with Confirmation of Payee. There is no QR standard in the UK.
Frequently asked questions
How do I bill days and expenses?
Days as a line, expenses as further lines with the receipt.
Can I evaluate assignments separately?
Yes, with cost centres per assignment.
Do interim managers in the UK have to charge VAT?
Only once they are VAT registered. Registration is required when taxable turnover passes £90,000 over any 12 months, or is expected to within the next 30 days. Below that you may register voluntarily. If you are not registered, you must not show VAT on your invoices.
Do interim managers in the UK need e-invoicing?
Not today. A mandate for B2B and B2G sales with VAT is planned from April 2029, and the details were still open as of October 2026. You can keep sending PDF invoices for now.
How long should interim managers keep invoices?
Keep VAT records for 6 years. You can store receipts digitally in Saldiqo. The legal duty to keep records stays with you.
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As of October 2026. General information, not legal or tax advice, without guarantee. For your case ask your tax adviser.