The reverse VAT formula
Adding VAT multiplies the net by (1 + rate). Removing it does the opposite: divide the gross by (1 + rate). At the 23% standard rate the divisor is 1.23, at 13.5% it is 1.135, at 9% it is 1.09 and at 4.8% it is 1.048. The zero rate has a divisor of 1, so the net and gross are the same number.
net = gross ÷ (1 + rate), then VAT = gross - net.
There is a shortcut for the VAT alone. The VAT fraction is rate ÷ (100 + rate). At 23% that is 23/123, which is about 0.187. Multiply any 23% gross price by 0.187 and you have the VAT inside it, give or take a cent. Accountants have used the fraction for decades because it works on a desk calculator without a second step.
The mistake that costs people money
Taking 23% off the gross does not work. Try it on €123: 23% of €123 is €28.29, which leaves €94.71. The true net is €100. The error is €5.29 on a small invoice and hundreds of euro on a van. The reason is simple. The 23% was charged on the net, so it is 23% of a smaller number than the gross. Divide, never subtract.
Worked examples: €100 gross at every Irish rate
The same €100 receipt contains a different amount of VAT depending on what was sold. Here is €100 gross worked at each rate Revenue publishes for 2026.
| Rate | Net | VAT | Gross |
|---|---|---|---|
| 23% | €81.30 | €18.70 | €100.00 |
| 13.5% | €88.11 | €11.89 | €100.00 |
| 9% | €91.74 | €8.26 | €100.00 |
| 4.8% | €95.42 | €4.58 | €100.00 |
| 0% | €100.00 | €0.00 | €100.00 |
Notice the 23% row. €100 with standard-rate VAT inside is €81.30 net and €18.70 VAT. That €18.70 is the VAT fraction at work: 23/123 of €100.
Worked examples: a real receipt
A tradesperson quotes €1,850 including VAT for repair work on a house. Repair services are at the 13.5% reduced rate, so the divisor is 1.135. €1,850 ÷ 1.135 = €1,629.96 net, and the VAT is €220.04. If the same job had been quoted at 23% by mistake the net would have shown as €1,504.07, understating the tradesperson’s income by almost €126.
| Rate | Net | VAT | Gross |
|---|---|---|---|
| 23% | €1,504.07 | €345.93 | €1,850.00 |
| 13.5% | €1,629.96 | €220.04 | €1,850.00 |
| 9% | €1,697.25 | €152.75 | €1,850.00 |
A restaurant bill of €86.50 is at 9% for the food (since 1 July 2026). €86.50 ÷ 1.09 = €79.36 net and €7.14 VAT. If the bill includes wine or a soft drink, those lines are at 23% and need to be split out first. See VAT on restaurants for how the split works.
When you need reverse VAT
- Expenses and VAT3 returns. Receipts show gross totals. To reclaim the VAT on a fuel bill or a hardware receipt you need the VAT figure, which means backing it out of the total. Our VAT3 guide covers where it goes.
- Pricing for consumers. Shops set a shelf price and then need to know what they actually keep. €49.99 at 23% is €40.64 net; the other €9.35 belongs to Revenue.
- Quotes from unregistered suppliers. If a supplier is below the registration threshold they charge no VAT, so there is nothing to remove. Check the invoice for a VAT number before you back anything out; our VAT number check validates the format.
- Comparing quotes. One quote says “plus VAT”, another says “inclusive”. Bring both to net before you compare.
Which rate to divide by
The rate depends on what was sold, not on who sold it. Most goods and services are at 23%. Building work, repairs, hotel stays and heating oil are at 13.5%. Restaurant meals, hot takeaway food, hairdressing, electricity and gas are at 9%. Most food, books and children’s clothes are at 0%, so there is no VAT to remove. The full list with examples is on the VAT rates page, and Revenue keeps a searchable database of specific items. If the receipt shows the rate, use that.
Need to go the other way and add VAT to a net price? The main VAT calculator starts in Add VAT mode. For a rate-specific tool try the 13.5% calculator or the 9% calculator.