TL;DR: If you’re VAT-registered or pay Corporation Tax, the safest habit is to treat tax money as already spent. A simple system is to estimate what you owe, ring-fence it into a separate pot, review it regularly, and then finalise it as you get closer to payment dates. Only then can you confidently define what cash is genuinely surplus.
Why businesses get caught out by tax
Tax bills often arrive long after the trading activity that created them. You might have a strong quarter, see a healthy bank balance, and assume you’re doing great, only to find that a VAT payment or Corporation Tax bill lands and the “spare” cash was never really spare.
The fix is boring but effective: make tax a routine. When you set aside tax steadily, you avoid the end-of-quarter or end-of-year scramble that forces tough decisions like delaying supplier payments or draining buffers.
VAT: the simplest way to stay safe
If you charge VAT on sales, the VAT you collect isn’t really yours. You’re just holding it for HMRC until it’s paid. That’s why many small businesses find it easiest to ringfence VAT as soon as it is received, rather than trying to rebuild the amount later.
If you reclaim VAT on costs, that can reduce what you owe, but it is safer to treat reclaims as a bonus rather than a guarantee. The exact calculation also depends on your VAT scheme, but the core principle is consistent: know your reporting periods, plan for the payment date, and keep the money separate from day-to-day spending.
Corporation Tax: plan throughout the year
Corporation Tax is based on taxable profit for your accounting period. That means it is driven by your accounts and tax rules, not by how much cash is sitting in the bank. The important part is timing: the profit may have happened months ago, but the payment is usually due later, when the cash may have already been used.
A practical way to avoid that stress is to review your profit-to-date regularly and set aside an estimated amount as you go. You can then adjust the estimate as the year progresses and you learn more about your true profitability.
A “tax pot” system you can actually stick to
You don’t necessarily need a complicated spreadsheet to get started (though many choose to make one). What matters most is a simple habit that you stick to, even in busy weeks.
Most businesses keep two separate pots: one for VAT and one for Corporation Tax. Those pots can be separate accounts or clearly labelled internal buckets. The point is to remove temptation and confusion, so tax money doesn’t get mixed into working capital.
Once the pots exist, consistency matters more than precision. Weekly or monthly transfers tend to work better than doing it “when you remember”, because they smooth the impact and make the numbers predictable.
It also helps to do a short monthly check, mainly to confirm:
- The pots still broadly match what you expect to owe
- You have not missed any key upcoming payment dates
- There are no big one-off costs likely to squeeze cash flow
Don’t forget the cash-flow pinch points
Tax rarely arrives alone. Cash-flow issues usually happen when tax payments coincide with other timing pressures like payroll, supplier runs, annual insurance renewals, and other lumpy costs. If you list those costs out for the next 12 months, you will often see exactly where the pressure points are before they happen.
The surplus cash bridge
Once VAT is ringfenced, Corporation Tax is realistically provided for, and you have covered near-term bills and held an operating buffer, it becomes much easier to define what cash is genuinely surplus. That is the cash that may be suitable for longer-term goals, including investing retained profits, depending on your time horizon and risk tolerance.
FAQs
Should I invest money I’ve set aside for VAT or Corporation Tax?
Only consider this if you’re confident you won’t need the cash before it’s due, and you’re comfortable with investment risk and the time it can take to sell and withdraw.
What’s the easiest “low-admin” approach?
Automate transfers into tax pots and do one monthly review. Consistency beats perfect accuracy.
What if my business is seasonal?
A rolling forecast helps. In high-revenue months, increase what you set aside so you are not caught out in quieter periods.
Is Corporation Tax based on invoices or cash received?
It depends on your accounting method and circumstances. Your accountant can confirm the basis used for your accounts and tax calculations.
What if I’m on the VAT Flat Rate Scheme or cash accounting?
Your VAT calculation changes, but ringfencing and planning around payment dates still matters just as much.
Important information
Capital at risk. The value of investments may go down as well as up, and you may get back less than you invest. Past performance is not indicative of future performance. ETF costs apply. Tax rules can change and any benefits depend on individual circumstances. If in doubt, consider professional advice.