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Quarterly VAT calculator: output and input VAT

Enter the VAT you charged on your quarter's invoices (output VAT) and the VAT you paid on your expenses (input VAT). You will see whether it comes out to pay or to carry forward, as on modelo 303.

Free · No sign-upReviewed on 6 November 2026

No sign-up: what you type is not saved.

Sample data

To pay to the tax office€1,800.00
Output VAT
€3,000.00
Deductible input VAT
− €1,200.00
Difference
€1,800.00

How it was calculated

  1. Difference = output − input: €3,000.00 − €1,200.00 = €1,800.00
  2. Amount to pay: €1,800.00 − €0.00 (carried over from earlier quarters) = €1,800.00

Indicative result: it does not replace an advisor's advice.

Let your modelo 303 prepare itself from your invoices and expenses

Taxes adds up the VAT on every invoice and expense and prepares an indicative modelo 303 draft.

See the Taxes module Create a free account

How is quarterly VAT calculated?

Each quarter you subtract the VAT you paid on purchases and deductible expenses (input VAT) from the VAT you charged on your invoices (output VAT). If the result is positive you pay it; if negative it is carried forward to later quarters. With €3,000 output and €1,200 input, you pay €1,800.

Which input VAT can I deduct?

The VAT on expenses linked to your activity and backed by an invoice. Not every expense is deductible and not all VAT is either: it depends on the expense and your activity. Check the VAT Act or ask your advisor.

What if it comes out negative?

If input VAT exceeds output VAT, the result is carried forward to later returns; in some cases a refund can be requested. Check your case with your advisor or the Tax Agency.

From the calculation to modelo 303

This calculator summarises the result. Modelo 303 breaks down the bases by VAT rate and has other boxes. FlexiFlow adds up the VAT on your invoices and expenses and prepares an indicative draft of modelo 303.

Worked example

Quarter invoices with €3,000.00 of output VAT and expenses with €1,200.00 of deductible input VAT: 3,000 − 1,200 = €1,800.00 to pay. If you also had €300 carried over from earlier quarters, you would pay €1,500.00.

How to use this tool

  1. Add up the VAT on your quarter's issued invoices.
  2. Add up the deductible VAT on your expenses.
  3. Read whether it comes out to pay or to carry forward.

Frequently asked questions

What are output and input VAT?

Output VAT is what you charge on your invoices; input VAT is what you pay on your expenses.

How much VAT do I have to pay each quarter?

The difference between output VAT and deductible input VAT, minus anything carried over from earlier quarters.

Is it the same as modelo 303?

It is the same basic calculation, but modelo 303 has more boxes and is filed on the Tax Agency's electronic office.

Is it a final figure?

No. It is indicative: confirm it with your advisor before filing.

Official sources

Keep reading

Reviewed on 6 November 2026. Indicative result: it does not replace an advisor's advice.

Taxes with indicative drafts of modelos 303 and 130

From your invoices and expenses, no spreadsheets.

See the module Create a free account