VAT Return Calculator

A VAT Return Calculator helps you work out an estimated VAT balance for a return period. It compares the VAT your business owes on sales and other outputs with the deductible input VAT you can reclaim on eligible purchases and expenses.

When the VAT due is higher than the VAT you can reclaim, the difference is normally the amount to pay. When the reclaimable input VAT is higher, you may have a VAT repayment due.

The calculator is useful for checking your figures before completing a VAT Return. Your actual return can also include adjustments, corrections, imports, special accounting scheme rules, and other figures that need to be reported to HMRC.

VAT Return Calculator for estimating VAT to pay or reclaim in the UK

How the VAT Return Calculator Estimates VAT Payable

The calculator starts with the VAT due on your sales and other outputs and compares it with the deductible input VAT for the same return period.

  • Enter the VAT due on taxable sales and other outputs.
  • Enter the input VAT that can be reclaimed on eligible business purchases and expenses.
  • Include relevant credit notes, refunds, and adjustments.
  • Add any other VAT due that applies to the return.
  • Compare the total VAT due with the reclaimable input VAT.
  • When the VAT due is higher, the difference is the amount to pay.
  • When the reclaimable input VAT is higher, the difference may be repayable.

For example, a business with £4,000 of VAT due and £2,500 of reclaimable input VAT would have £1,500 to pay based on those figures.

HMRC uses Box 3 for total VAT due and Box 4 for VAT reclaimed on purchases and other inputs. Box 5 is the difference between the two and shows the net VAT to pay or reclaim.

Box 3, Box 4 and Box 5 on a VAT Return

VAT Return Box 3 Box 4 and Box 5 calculation explained

These three boxes are closely linked to the basic VAT calculation:

VAT Return BoxWhat It Shows
Box 3Total VAT due for the period. HMRC describes this as the VAT from Box 1 and Box 2 added together.
Box 4Total deductible VAT reclaimed on purchases and other inputs for the period.
Box 5The difference between Box 3 and Box 4. This is the net VAT to pay to HMRC or reclaim.

The basic Box 5 calculation is:

VAT to pay or reclaim = Box 3 − Box 4

For example:

  • Box 3 = £5,000
  • Box 4 = £3,200
  • Box 5 = £1,800 to pay

When Box 3 is lower than Box 4, the difference represents a repayment due, subject to HMRC rules and any checks that may apply.

Box 3 and Box 4 are not simply the total VAT appearing on every sales and purchase invoice. Box 4 contains deductible input VAT, so the business must first establish which input VAT is eligible for recovery.

Output VAT, Input VAT and Net VAT Due

VAT TermWhat It Means
Output VATVAT due on taxable sales and other outputs.
Input VATVAT paid on eligible business purchases and expenses that can be reclaimed.
Box 3Total VAT due for the VAT Return period.
Box 4Total deductible VAT reclaimed on purchases and other inputs.
Box 5Net VAT to pay to HMRC or reclaim after subtracting Box 4 from Box 3.

A business cannot automatically reclaim every amount of VAT paid on its purchases. The amount entered for Box 4 needs to reflect the VAT that is actually deductible under the rules. Proper VAT records and supporting invoices may also be needed for the claim.

Output VAT and input VAT comparison for UK businesses

VAT Return Figures to Gather Before Calculating

Before working out the VAT balance, gather the figures that belong to the same VAT Return period:

  • VAT due on taxable sales and other outputs
  • VAT due on other transactions that need to be included
  • Deductible input VAT on eligible purchases and expenses
  • Credit notes and refunds
  • Import VAT and other relevant VAT adjustments
  • Purchase and sales invoices
  • The start and end dates of the VAT Return period
  • Any adjustments required under your VAT accounting scheme

Using figures from the correct accounting period helps prevent sales or purchases from being included in the wrong return. It also makes it easier to identify input VAT that cannot be reclaimed.

Businesses using special VAT schemes need to follow the rules that apply to their scheme. HMRC provides separate guidance for schemes such as cash accounting, annual accounting, flat rate and margin schemes.

VAT Return figures checklist including sales purchases invoices and adjustments

How Is VAT to Pay Calculated?

VAT to pay is calculated by subtracting the deductible input VAT from the total VAT due for the return period.

Formula:

VAT to Pay = Box 3 − Box 4

For example, suppose:

  • Total VAT due in Box 3 = £6,500
  • Deductible input VAT in Box 4 = £4,100

The calculation is:

£6,500 − £4,100 = £2,400

The Box 5 figure would therefore be £2,400 to pay.

When Box 4 is higher than Box 3, the calculation produces a negative difference. In that situation, the business may be due a VAT repayment rather than having VAT to pay. HMRC confirms that Box 5 is the difference between Boxes 3 and 4.

VAT to pay calculation showing Box 3 minus Box 4

VAT Return Calculator

A VAT repayment may arise when the deductible input VAT for a return period is higher than the total VAT due.

For example, a business has:

  • Box 3 = £2,000
  • Box 4 = £3,200

The difference is £1,200, so the business may have £1,200 to reclaim.

The final repayment still depends on the figures included in the VAT Return and any checks or adjustments that apply.

FAQs

Yes, but the figures need to follow the VAT Cash Accounting Scheme rules. Under cash accounting, output VAT is generally based on payments received rather than invoices issued, while input VAT is generally based on payments made rather than invoices received. There are also specific rules for imports and certain transactions.

Partial exemption can limit the amount of input VAT a business can reclaim. When a business makes both taxable and exempt supplies, it may need to calculate the recoverable portion of its input VAT before entering the amount used in the VAT calculation.

The calculator should use the recoverable amount rather than simply subtracting all VAT paid on purchases.

No. A calculator can help you check the VAT balance, but it does not submit a VAT Return to HMRC. The official return must contain the figures required for the relevant accounting period and follow the VAT rules that apply to your business.

HMRC’s guidance explains what needs to be entered in each VAT Return box and how the figures should be checked before submission.

The treatment depends on the VAT accounting method and the tax point for the transaction. Under normal VAT accounting, the relevant tax point helps determine which return includes the transaction. Businesses using cash accounting generally use payments received and made instead.

A late invoice should not simply be added to the current return without checking which accounting period it belongs to.

Yes. You can use the figures available so far to track your expected VAT position during the quarter. The balance can change as more sales, purchases, credit notes, refunds, and adjustments are recorded.

A running calculation is useful for monitoring the position, but the final figures should cover the complete VAT Return period.

A previous-return correction should be identified separately from the current period’s ordinary sales and purchase figures. The way an error is corrected depends on the size and type of the error and the applicable HMRC correction rules.

Once the correction has been worked out, include it in the appropriate calculation rather than changing unrelated current-period figures.

Yes. Import VAT can affect the VAT Return, depending on how the import is accounted for. For example, businesses using postponed VAT accounting include eligible import VAT in the relevant VAT Return boxes. HMRC provides specific rules for reporting and reclaiming postponed import VAT.

When Box 3 is higher than Box 4, the difference is the net VAT amount due to HMRC, subject to the other figures and rules applying to the return.

For example, Box 3 of £4,500 minus Box 4 of £3,000 gives £1,500 in Box 5 to pay.

Final Thoughts

A VAT Return Calculator gives you a simple way to check the VAT position for a return period. The key figures are the total VAT due in Box 3 and the deductible input VAT in Box 4. Subtracting Box 4 from Box 3 gives the Box 5 amount to pay or reclaim.

The result depends on using the correct figures for the same VAT period and applying the rules that affect your business. Credit notes, refunds, imports, partial exemption, corrections, and special VAT schemes can all change the final calculation.

Use the calculator as a checking tool before preparing the official VAT Return. Before submitting, compare the calculated balance with your VAT records and make sure the figures have been entered into the correct boxes.

Before submitting your next VAT Return, have you checked that your Box 3 and Box 4 figures give the correct Box 5 amount?