You are about to send an invoice, check a supplier bill, or total a VAT return quarter, and you need the VAT number fast. A VAT ready reckoner is a lookup table of VAT due on common amounts at the UK rates of 20 percent and 5 percent. Below are the tables for adding and removing VAT at both rates, the shortcut maths behind them, and a worked quarter check that shows how the tables fit real bookkeeping.
What is a VAT ready reckoner?
A VAT ready reckoner is a reference table that shows the VAT due on common amounts without a calculator. You find your amount in the table, read across to the VAT column, and you have the answer in seconds. Ready reckoners come in two directions: adding VAT to a net price, and removing VAT from a gross price that already includes it, each at the 20 percent standard rate and the 5 percent reduced rate.
These tables suit quick checks: quoting a client, reviewing a supplier invoice, or sanity-checking software totals before you file. They do not replace your VAT return, but they catch the small errors that creep in when you type numbers by hand. Searchers usually arrive here with one job: to check the VAT due on a specific amount at 20 percent or 5 percent right now, so this guide answers that job first and explains the maths after.
How much VAT do you add at 20 percent?
To add 20 percent VAT, multiply the net amount by 0.20 to get the VAT, and multiply by 1.20 to get the gross total. The table below does that for the amounts freelancers and small businesses look up most, so you can read the answer straight off.
| Net price (ex-VAT) | VAT at 20% | Gross price (inc-VAT) |
|---|---|---|
| £5.00 | £1.00 | £6.00 |
| £10.00 | £2.00 | £12.00 |
| £15.00 | £3.00 | £18.00 |
| £20.00 | £4.00 | £24.00 |
| £25.00 | £5.00 | £30.00 |
| £50.00 | £10.00 | £60.00 |
| £75.00 | £15.00 | £90.00 |
| £100.00 | £20.00 | £120.00 |
| £150.00 | £30.00 | £180.00 |
| £250.00 | £50.00 | £300.00 |
| £500.00 | £100.00 | £600.00 |
| £1,000.00 | £200.00 | £1,200.00 |
| £2,500.00 | £500.00 | £3,000.00 |
| £5,000.00 | £1,000.00 | £6,000.00 |
| £10,000.00 | £2,000.00 | £12,000.00 |
Notice the pattern at 20 percent: the VAT is always exactly one fifth of the net. A £100 invoice carries £20 of VAT, a £1,000 invoice carries £200. Once you see that, you can estimate any amount in your head: take the net, divide by 5, and that is the VAT to add.
Tip: when your amount is not in the table, split it. VAT on £350 is VAT on £250 (£50) plus VAT on £100 (£20), which is £70. Two lookups beat one calculation, and you are less likely to mistype.
How do you remove 20 percent VAT from a gross price?
To remove 20 percent VAT, divide the gross price by 1.20 to get the net, or divide the gross by 6 to get the VAT directly. Subtracting 20 percent from the gross gives the wrong answer, because the 20 percent was added to the net, not the gross. The table below gives the correct figures for common gross amounts.
| Gross price (inc-VAT) | VAT at 20% | Net price (ex-VAT) |
|---|---|---|
| £12.00 | £2.00 | £10.00 |
| £60.00 | £10.00 | £50.00 |
| £120.00 | £20.00 | £100.00 |
| £240.00 | £40.00 | £200.00 |
| £300.00 | £50.00 | £250.00 |
| £600.00 | £100.00 | £500.00 |
| £1,200.00 | £200.00 | £1,000.00 |
| £6,000.00 | £1,000.00 | £5,000.00 |
The divide-by-6 trick is the heart of reverse VAT at 20 percent. Because VAT at 20 percent is one sixth of the gross total, a £600 supplier invoice contains exactly £100 of VAT (£600 / 6), leaving £500 net. If you want the full method behind this, our guide to calculating VAT walks through adding, removing and reversing VAT with every formula. Use the table above when you are checking receipts and supplier invoices that arrive with VAT already included.
What does VAT look like at the 5 percent reduced rate?
At the 5 percent reduced rate you multiply the net by 0.05 to add VAT, or divide the gross by 21 to extract it. The reduced rate applies to domestic energy, children’s car seats, and certain energy-saving materials, so freelancers meet it mostly on home office energy bills and a handful of supplies. Both directions are below.
| Net price (ex-VAT) | VAT at 5% | Gross price (inc-VAT) |
|---|---|---|
| £10.00 | £0.50 | £10.50 |
| £20.00 | £1.00 | £21.00 |
| £50.00 | £2.50 | £52.50 |
| £100.00 | £5.00 | £105.00 |
| £200.00 | £10.00 | £210.00 |
| £500.00 | £25.00 | £525.00 |
| £1,000.00 | £50.00 | £1,050.00 |
| £5,000.00 | £250.00 | £5,250.00 |
| Gross price (inc-VAT) | VAT at 5% | Net price (ex-VAT) |
|---|---|---|
| £10.50 | £0.50 | £10.00 |
| £21.00 | £1.00 | £20.00 |
| £52.50 | £2.50 | £50.00 |
| £105.00 | £5.00 | £100.00 |
| £210.00 | £10.00 | £200.00 |
| £525.00 | £25.00 | £500.00 |
| £1,050.00 | £50.00 | £1,000.00 |
| £2,100.00 | £100.00 | £2,000.00 |
The 5 percent fraction works like the 20 percent one: the VAT element is one twenty-first of the gross. A £105 energy bill contains £5 of VAT (£105 / 21), leaving £100 net. If the rate feels unfamiliar, that is because most freelance work is standard-rated; the reduced rate shows up in the margins of your expense receipts.
Watch out: from 1 October 2026 to 31 March 2027, VAT on domestic electricity is temporarily cut from 5 percent to 0 percent as a cost-of-living measure, while domestic gas stays at 5 percent. If a home electricity bill in this window shows no VAT, that is why. Do not use the 5 percent table for bills charged at the temporary 0 percent rate.
What is the shortcut maths behind these tables?
Every cell in the tables above comes from four short formulas. Learn them and the tables become a memory aid rather than a crutch. At 20 percent, adding VAT means multiplying by 1.20, and extracting VAT means dividing by 6 (the VAT fraction is one sixth). At 5 percent, adding VAT means multiplying by 1.05, and extracting VAT means dividing by 21 (the VAT fraction is one twenty-first).
Two details trip people up. First, rounding: VAT fractions can produce fractions of a penny. A £100.01 receipt at 20 percent gives VAT of £100.01 / 6 = £16.6683, which you round to the nearest penny: £16.67 VAT, £83.34 net. HMRC accepts rounding to the nearest penny on invoices, so round once, at the end, not at every step. Second, the zero rate and exemption are not the same as 5 percent: a zero-rated supply (most food, children’s clothes) is still taxable at 0 percent and counts toward the £90,000 VAT registration threshold, while exempt supplies (insurance, health services) sit outside VAT entirely and do not. Check which one your work falls under in our UK VAT rates guide before you use any table.
Tip: if you only remember two numbers, remember 6 and 21. Gross divided by 6 pulls out 20 percent VAT, gross divided by 21 pulls out 5 percent VAT. These two divisions answer almost every reverse-VAT question you will ever face.
How do you check one quarter of invoices against these tables?
This is where a ready reckoner earns its keep: spot-checking a quarter’s figures before you file your VAT return. Work through the example below with the tables above and see how fast it goes. Assumptions: UK freelancer, VAT-registered, quarterly return, all sales standard-rated at 20 percent, and the two purchase receipts as stated.
Three sales invoices went out in the quarter. The £1,200 invoice contains £200 of VAT (£1,200 / 6). The £600 invoice contains £100 of VAT (£600 / 6). The £300 invoice contains £50 of VAT (£300 / 6). Total output tax for the quarter is £200 + £100 + £50 = £350. That is your Box 1 figure.
Two purchase receipts qualify as business expenses with VAT. A £120 receipt at 20 percent contains £20 of VAT (£120 / 6). A £63 home office electricity bill at 5 percent contains £3 of VAT (£63 / 21). Total input tax is £20 + £3 = £23. That is your Box 4 figure.
The VAT due is output tax minus input tax: £350 – £23 = £327. If your accounting software says anything different, one of its line items is wrong, and the reckoner tables just told you which direction to look. A mismatch on output tax means a sales invoice is miscoded; a mismatch on input tax means a receipt got the wrong rate.
Tip: run this five-minute reckoner check the day before every return is due. Most VAT-registered sole traders file quarterly under Making Tax Digital, and the penalty for a late or inaccurate return costs far more than five minutes of table lookups.
What are the five mistakes that make ready-reckoner checks wrong?
The tables are exact, but the way people use them is not. These five errors account for almost every wrong figure seen in practice, and each one is easy to avoid once you have named it.
1. Subtracting 20 percent from the gross. A £120 gross is not £96 net plus £24 VAT. The VAT is £20 and the net is £100. Always divide by 6 or 1.20, never subtract 20 percent.
2. Using 20 percent on a reduced-rate supply. Home energy, children’s car seats and energy-saving materials are 5 percent, not 20. Check the rate before you reach for a table.
3. Rounding at every step. Round once, at the end, to the nearest penny. Rounding each line of a long invoice accumulates small errors that turn into a real mismatch on the return.
4. Treating zero-rated and exempt as the same thing. Zero-rated sales still count toward the £90,000 VAT registration threshold and go on your return; exempt sales are outside VAT altogether. Confusing them affects registration decisions, not just the tables.
5. Mixing tax points across quarters. The reckoner tells you the VAT on an invoice, but the VAT return cares about the tax point date, not when you paid or were paid. An invoice dated in the old quarter belongs to the old quarter’s return even if the money arrived in the new one.
If an amount you need is not in any table, LancerBill’s VAT calculator adds or removes VAT at 20 percent, 5 percent and zero in one click, and it handles the rounding for you. When you are building the invoice itself, our free invoice generator applies VAT per line item, and if you are checking what a supplier charged you, the receipt generator is the matching tool for receipts.
Key takeaways
- Adding 20 percent VAT: multiply the net by 1.20. Removing it: divide the gross by 6 or 1.20.
- Adding 5 percent VAT: multiply the net by 1.05. Removing it: divide the gross by 21 or 1.05.
- Never subtract the rate from the gross: £120 at 20 percent is £100 net plus £20 VAT, not £96 plus £24.
- Round once, at the end, to the nearest penny; rounding every line creates return mismatches.
- Spot-check one quarter of invoices against the tables before filing; a mismatch tells you which line to investigate.
- Rates last reviewed: October 2026.
Frequently asked questions
What is the VAT on £100 at 20 percent?
£20 of VAT, making the gross total £120. Multiply the net by 0.20 for the VAT (£100 x 0.20 = £20) or by 1.20 for the gross (£100 x 1.20 = £120). If the £100 already includes VAT, the VAT element is £100 / 6 = £16.67 and the net is £83.33.
How do you quickly calculate 20 percent VAT in your head?
For adding VAT, divide the net by 5: £250 / 5 = £50 of VAT. For removing VAT from a gross, divide the gross by 6: £300 / 6 = £50 of VAT, leaving £250 net. These two mental shortcuts cover the most common checks.
What is the VAT fraction at 5 percent?
One twenty-first (1/21). Divide a VAT-inclusive amount by 21 to find the VAT element: £210 / 21 = £10 of VAT, leaving £200 net. This is the 5 percent equivalent of the well-known divide-by-6 trick at 20 percent.
Does the ready reckoner replace a VAT calculator or accounting software?
No. The tables are for quick lookups and spot checks. Use LancerBill’s VAT calculator for exact figures on arbitrary amounts, and accounting software such as Xero, FreeAgent, QuickBooks or Sage for your actual VAT return figures, which you file quarterly under Making Tax Digital.
Why does my electricity bill show 0 percent VAT instead of 5 percent?
VAT on domestic electricity is temporarily cut to 0 percent from 1 October 2026 to 31 March 2027 as a cost-of-living measure; domestic gas stays at 5 percent. Suppliers apply the change automatically, so bills in this window legitimately show no VAT on electricity.
Do zero-rated sales count toward the VAT registration threshold?
Yes. Zero-rated supplies (such as most food and children’s clothes) are still taxable supplies at 0 percent, so they count toward the £90,000 VAT registration threshold. Exempt supplies (such as insurance and health services) are outside VAT and do not count.
Rates last reviewed: October 2026, verified against HMRC’s published VAT rates (20 percent standard, 5 percent reduced, £90,000 registration threshold) and GOV.UK guidance on the temporary 1 October 2026 to 31 March 2027 domestic electricity cut. This guide is for general information only and is not financial, tax or legal advice.