Proforma invoice vs tax invoice UK (2026): CIS, VAT and when to use each
Proforma vs tax invoice UK, short answer: a proforma is a payment request / quotation-style document that is not a VAT invoice and does not create output tax by itself. A tax invoice (VAT invoice) is the formal supply document a VAT-registered business issues with the fields HMRC expects. Who pays is the customer named on either document. CIS is separate: it may apply when a CIS contractor pays you for construction operations — soften with HMRC’s CIS overview. A private householder on their own home is usually not CIS. VAT registration threshold is £90,000 — if you are registered, charge and show VAT only on a proper tax invoice (or compliant equivalent), not by mis-labelling a proforma.
Use this page to choose proforma vs tax invoice before you send the PDF. It is not a stage, progress, deposit, retention or variation template — those live on their own sisters. Figures are illustrative only. Need a real invoice PDF now? Open the free invoice generator (Free: 5 invoices; Pro £7.99 / Pro+ £12.99).
Who pays, CIS and VAT on proforma vs tax invoice
Document | Who typically pays | CIS? | VAT? |
|---|---|---|---|
Proforma | Customer asked to pay in advance or confirm totals | CIS may still sit on the later tax invoice / payment — do not invent CIS lines on a labelled proforma unless your accountant agrees | Not a VAT invoice — do not treat it as creating output tax |
Tax invoice (VAT-registered) | Customer for a taxable supply | May apply when a CIS contractor pays for construction ops | Show net / VAT / gross; threshold £90,000 |
Invoice (not VAT-registered) | Customer for the supply | Same CIS tests when a contractor pays | Net only — do not charge VAT |
Householder own-home job | Private client | Usually no CIS | VAT only if you are registered |
InvoiceAdept does not file CIS300, VAT returns, MTD or Self Assessment.
What a proforma is (and is not)
A proforma is commonly used to ask for payment before goods or services are supplied, or to confirm line totals before a formal invoice. It should be clearly labelled proforma so accounts payable does not post it as a VAT invoice. It is not a substitute for a tax invoice once the supply is made and you are VAT-registered.
Proforma cue | Practical note |
|---|---|
Label | Say “PROFORMA — not a VAT invoice” |
Payment request | Useful for deposits / materials up front — see also the deposit template when the PDF is a true deposit invoice |
After supply | Issue a proper invoice / tax invoice; do not leave the file as a proforma forever |
VAT fields | Avoid presenting a full VAT breakdown as if it were a tax invoice |
What a tax invoice must include
Field | Always? | Notes |
|---|---|---|
Your name / business name and address | Yes | Match registration details |
Customer name and address | Yes | Ltd = registered name where practical |
Unique sequential invoice number | Yes | e.g. INV-2026-0142 |
Invoice date | Yes | Date of issue |
Tax point / supply date | If different and VAT-registered | When the supply is treated as taking place |
Description of supply | Yes | What was supplied; site / job refs help |
Unit price, quantity, net amount | Yes | Clear arithmetic |
VAT rate(s) and VAT amount | If VAT-registered | Show net, VAT, gross |
VAT registration number | If VAT-registered | On the tax invoice |
CIS narrative / UTR cues | When a CIS contractor pays within scope | Omit on true householder PDFs |
Bank details / payment terms | Strongly recommended | Due date and account name |
If you are not VAT-registered, still issue a clear commercial invoice — just without VAT lines.
Key differences at a glance
Topic | Proforma | Tax invoice |
|---|---|---|
Legal / VAT status | Payment request / estimate style — not a VAT invoice | Formal VAT invoice when you are registered |
When to send | Often before supply or to confirm totals | When the supply is made (or as your tax point rules require) |
Customer accounts | Should not be posted as input VAT | May support input VAT recovery when rules met |
Your books | Does not by itself create output VAT | Drives output VAT when registered |
Label clarity | Must say proforma | Say invoice / tax invoice; unique number |
Copy-paste example (illustrative)
Scenario: VAT-registered electrician. Customer wants materials paid before start. Proforma first; tax invoice after supply. Householder job — usually no CIS. Figures illustrative.
Document | Lines (illustrative) | What to show |
|---|---|---|
Proforma PF-2026-09 | Materials package for kitchen first fix — £500 net | “PROFORMA — not a VAT invoice. VAT will appear on the tax invoice when supplied.” |
Tax invoice INV-2026-0142 | First-fix labour + materials supplied | Net £1,200 + VAT 20% £240 = gross £1,440; VAT number; no CIS (householder) |
Do not send a document that looks like a full VAT invoice while still calling it a proforma. Soften edge cases with your accountant.
CIS and VAT cues
Topic | Practical rule |
|---|---|
VAT threshold | £90,000 |
Not VAT-registered | Commercial invoice without VAT; never invent VAT |
CIS contractor pays for construction ops | CIS may apply on the labour / CIS base — usually on the invoice that matches payment, not a casual proforma label |
Householder own home | Usually no CIS |
Domestic reverse charge | Never on a householder; contractor-to-contractor tests only |
Deemed contractor framing | £3 million construction-spend test — not £1 million |
InvoiceAdept | Does not file CIS300, VAT, MTD or Self Assessment |
Common mistakes
Mistake | Fix |
|---|---|
Calling a VAT invoice a proforma | Label correctly; issue a numbered tax invoice for the supply |
Leaving a paid proforma as the only document | Issue the formal invoice after supply |
Charging VAT when not registered | Net only until registered |
Putting CIS on a householder PDF | Remove CIS narrative for own-home householders |
Using a proforma to claim input VAT | Customers generally need a valid tax invoice — soften with their accountant |
No unique invoice number on the tax invoice | Use a sequential number series |
Practical workflow for UK trades
1) Agree scope and price. 2) If you need money before supply, send a clearly labelled proforma or a proper deposit invoice when that is the contract shape. 3) Do the work. 4) Issue the invoice / tax invoice with the right CIS and VAT facts. 5) Keep both documents and payment trail for your records.
Frequently asked questions
Is a proforma invoice legally the same as a tax invoice?
No. A proforma is typically a payment request or confirmation document. A tax invoice is the VAT invoice a registered business issues for a taxable supply.
Can I charge VAT on a proforma?
Do not treat a proforma as creating output VAT. If you are VAT-registered, show VAT on the proper tax invoice for the supply. Soften wording with your accountant.
What if I am not VAT-registered?
Issue a clear commercial invoice without VAT. The VAT threshold is £90,000.
Does CIS apply to proformas?
CIS is about construction operations and who pays you. Householders on their own home are usually outside CIS. When a CIS contractor pays, deductions usually sit with the invoice/payment trail — soften with HMRC / your accountant.
Should I use a deposit invoice instead?
If the PDF is an upfront deposit under the contract, use the deposit invoice template. Use a proforma when you only need a labelled payment request before the formal invoice.
Can a customer reclaim VAT from a proforma?
Generally they need a valid tax invoice. Soften with their accountant — do not invent reclaim advice.
Do I need both documents every time?
Not always. Many jobs only need the invoice. Use a proforma when you specifically need a pre-supply payment request without calling it a VAT invoice.
Where can I build the invoice PDF?
Use the InvoiceAdept free invoice generator — Free covers 5 invoices; Pro £7.99 and Pro+ £12.99.
Next step: issue the right document
Label proformas clearly, issue a proper tax invoice when you are VAT-registered and the supply is made, keep householder vs CIS contractor facts straight, and use the £90,000 VAT threshold only as the registration cue. Open the free invoice generator when you are ready to send the numbered invoice. InvoiceAdept does not file CIS300, VAT returns, MTD or Self Assessment for you.
Last reviewed: 17 September 2026.
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