UK VAT Return Calculator
Enter your figures in the boxes below. The calculator handles the two computed boxes — Box 3 (total VAT due) and Box 5 (VAT payable or refund) — automatically. Use this as a pre-flight check before filing through your MTD software.
Box-by-box guide
The VAT100 has nine numbered boxes. Boxes 1–5 cover the VAT amounts. Boxes 6–9 cover the net values. Two of the boxes — 3 and 5 — are computed from the others.
| Box | What it captures | Notes |
|---|---|---|
| Box 1 | VAT due on sales and other outputs | Output VAT charged to customers in the period |
| Box 2 | VAT due on acquisitions from EU member states (NI only) | Zero for Great Britain businesses with no NI activity |
| Box 3 | Total VAT due — Box 1 + Box 2 | Auto-calculated by software |
| Box 4 | VAT reclaimed on purchases and other inputs | Includes Postponed VAT Accounting, capital goods scheme, pre-registration |
| Box 5 | Net VAT payable or refundable — Box 3 − Box 4 | Positive: pay HMRC. Negative: refund due. |
| Box 6 | Total value of sales excluding VAT | Includes zero-rated and exempt |
| Box 7 | Total value of purchases excluding VAT | Includes zero-rated and exempt |
| Box 8 | Value of goods supplied from NI to EU | Goods only, not services |
| Box 9 | Value of goods acquired in NI from EU | Goods only, not services |
Postponed VAT Accounting on the return
Import VAT under Postponed VAT Accounting (PVA) appears in both Box 1 and Box 4. The two entries cancel out for a fully taxable business — cash-neutral but visible on the return.
The figures come from the Monthly Postponed Import VAT Statement (MPIVS), downloaded from the CDS portal at the start of each month. Use the MPIVS figure, not the freight forwarder's estimate or the supplier invoice value. Partially exempt businesses must restrict the Box 4 entry by their recovery percentage.
Cash accounting vs invoice basis
The basis you use changes when VAT enters the boxes, not how much. Standard (invoice) basis: VAT on a sale is reported in the period of the invoice. Cash basis: reported in the period the customer pays.
Cash accounting helps cash flow if customers are slow to pay — you do not pay HMRC on VAT you have not collected. It is available to businesses with taxable turnover under £1.35 million. You leave the scheme when turnover passes £1.6 million. Choose at registration on form VAT1, or write to HMRC to change later.
Worked example
Small consultancy — Q2 2026 return
Net sales (all standard-rated): £60,000. VAT charged at 20%: £12,000. Box 1 = £12,000.
Net purchases: £22,500. Input VAT on purchases: £4,500. Box 4 = £4,500.
No NI activity. Boxes 2, 8, 9 = £0.
Box 3: £12,000 + £0 = £12,000
Box 5: £12,000 − £4,500 = £7,500 payable
Box 6: £60,000 (net sales)
Box 7: £22,500 (net purchases)
Payment due to HMRC: 7 days plus one month after period end. Direct debit payers get an extra three working days.
Common errors per box
- Box 1 — Flat Rate Scheme users putting actual VAT charged instead of flat-rate VAT. FRS users compute Box 1 as gross turnover × flat rate, not the 20% they charged customers.
- Box 1 — missing PVA entries. Import VAT under PVA must be added here, not just to Box 4.
- Box 4 — claiming blocked VAT. Client entertainment, most cars with private use, and personal expenditure should not appear in Box 4.
- Box 4 — duplicate pre-registration reclaim. Pre-registration goods/services can only be claimed once, on the first return.
- Box 6 — leaving out zero-rated and exempt supplies. Box 6 totals all sales, not just taxable ones.
- Box 7 — netting purchase returns wrong. Credit notes for returned goods reduce Box 7 — they do not go in Box 6.
- Boxes 8 / 9 — including services. Only goods movements between NI and the EU belong here.
- Wrong period. Filing the current quarter's figures against the previous quarter window. Always check the period end date on the return summary screen before submitting.
When the return is due
The filing and payment deadline is one month and seven days after the end of the VAT period. So a quarter ending 31 March must be filed and paid by 7 May. Direct debit payers get an extra three working days for payment but not for filing.
Annual accounting users file once a year, with the return due two months after year-end. Monthly filers (typically refund-position businesses) file monthly under the same one-month-seven-day rule.
Frequently asked questions
What is the UK VAT100 form?
The VAT100 is the digital UK VAT return submitted through Making Tax Digital software each quarter.
It has nine numbered boxes covering output VAT, input VAT, net values of sales and purchases, and the small remaining categories for Northern Ireland EU trade. The return is filed via API to HMRC — manual portal entry was retired in November 2022. You file even if there is no activity in the period (a "nil return").
How do I calculate Box 1?
Box 1 is total output VAT on sales — VAT charged to customers in the VAT period.
Include VAT on UK sales at 20%, 5% and 0% rates, VAT on services to non-UK customers where UK VAT applies, and any output adjustments. Excludes VAT on exempt supplies. For Flat Rate Scheme users, Box 1 is gross turnover × flat rate, not the VAT actually charged. Most accounting software fills Box 1 automatically.
What goes in Box 2?
Box 2 is VAT due on acquisitions from EU member states into Northern Ireland.
For mainland Great Britain importers, Box 2 will normally be zero — those imports use Postponed VAT Accounting in Box 1 instead. Calculate by multiplying the net invoice value by 20% (or the appropriate rate). The matching input VAT goes in Box 4. Only NI businesses or those with NI supply chains touch this box.
How do I calculate Box 4?
Box 4 is total input VAT you can reclaim — UK purchases, PVA imports, and EU acquisitions to NI.
Excludes blocked VAT (client entertainment, most cars with private use, non-business purchases). Keep the VAT invoice for every reclaim — HMRC requests them in compliance checks. Include partial exemption adjustments and capital goods scheme entries here. Pre-registration input VAT goes here on the first return only.
What is Box 3?
Box 3 is total VAT due to HMRC before reclaiming input VAT. Formula: Box 3 = Box 1 + Box 2.
Accounting software calculates Box 3 automatically. The figure represents the output side of the return — what the business owes before deducting purchases. Box 3 minus Box 4 gives Box 5, the actual amount payable (or refund due if negative). Never override Box 3 manually unless correcting a clear software error.
What is Box 5?
Box 5 is the net VAT payable to HMRC or refundable from HMRC. Formula: Box 3 − Box 4.
A positive Box 5 means you owe HMRC; a negative Box 5 means HMRC owes you. Payment is due one month and seven days after the period end. Refunds usually arrive within 30 days of return submission, though HMRC may delay refunds while verifying figures or running a compliance check.
What are Boxes 6 and 7?
Box 6 is total net sales for the period. Box 7 is total net purchases.
Include zero-rated and exempt supplies in Box 6 if you make them. Box 6 totals are what HMRC uses to test the 1% error correction limit. Most accounting packages fill Boxes 6 and 7 automatically from invoice and bill data. Credit notes reduce the relevant box, not the opposite one.
What goes in Boxes 8 and 9?
Box 8: net value of goods supplied from NI to EU. Box 9: net value of goods acquired in NI from EU.
For Great Britain businesses with no NI activity, both boxes are zero. The boxes are leftovers from EU acquisition reporting and only apply under the Windsor Framework. Services and Great Britain imports do not appear in Boxes 8 or 9. Common misuse: putting all EU trade here regardless of NI involvement.
How do I handle Postponed VAT Accounting on the return?
Enter the import VAT figure from the Monthly Postponed Import VAT Statement (MPIVS) in both Box 1 and Box 4.
The two entries cancel out for fully taxable businesses — cash-neutral. Use the actual MPIVS figure, not the supplier invoice value. Download the MPIVS from the Customs Declaration Service (CDS) portal each month. Partially exempt businesses must restrict the Box 4 entry by their recovery percentage.
When is the VAT return due?
One month and seven days after the end of the VAT period. Direct debit payers get an extra three working days.
A quarter ending 31 March must be filed and paid by 7 May. Annual accounting users have two months. Late returns trigger the points-based penalty system — one point per late return, with a £200 fixed penalty once you hit the threshold (4 for quarterly, 5 for monthly, 2 for annual).
What if I file a nil return?
Still required. Enter zeros in every box and submit through MTD software.
Missing a nil return counts the same as missing a return with figures and adds a point under the points-based penalty system. The same one-month-seven-day deadline applies. Common with seasonal businesses, new startups, and dormant entities. Once back in activity, normal returns resume from the next period.
Can I correct errors on a previous return?
Net errors under £10,000, or under 1% of Box 6 turnover (capped at £50,000), can be corrected on the next return.
Adjust Box 1 or Box 4 on the next return. Larger errors must be reported separately on form VAT652. Deliberate errors must always be disclosed regardless of size. Errors beyond 4 years are time-barred. Keep working papers showing how each adjustment was calculated — HMRC requests them in compliance checks.
What is Making Tax Digital for VAT?
MTD requires VAT-registered businesses to keep digital records and submit returns via API-linked software since April 2022.
Manual entry into the HMRC portal is no longer accepted. Approved software includes Xero, QuickBooks, FreeAgent, Sage, and Zoho Books. Spreadsheets are allowed if connected to bridging software that submits via API. Manual re-keying between systems breaks the digital link and fails the MTD test.
Sources and references
- HMRC VAT Notice 700/12 — How to fill in your VAT return
- HMRC — Making Tax Digital for VAT
- HMRC — Postponed Import VAT Statements
- HMRC — Form VAT652 for error correction