Leverage ratios get quoted like a badge of honour: 5:1 for the cautious, 30:1 for the serious. Strip away the marketing and a ratio is just a fraction in a suit. It tells you how much of a position's total value you must fund yourself, and almost everything else follows from that single number — how much a bad week costs, how much room a trade has to breathe, and how quickly your broker steps in when it doesn't.
What a leverage ratio actually measures
Start with the arithmetic, because it clears up most of the confusion. When a broker offers 5:1, it will let you control £5 of market exposure for every £1 of your own money posted as margin. Invert that and you get the margin requirement: one fifth of the notional position value, or 20%.
- 5:1 — 20% margin. A £30,000 position needs £6,000 of your capital.
- 10:1 — 10% margin. The same position needs £3,000.
- 30:1 — roughly 3.3% margin. The same position needs about £1,000.
Notice that "notional" does the heavy lifting here. Your £30,000 position is the total market exposure, not the cash you handed over. The margin is money set aside rather than spent, but it is still capital that can't do anything else while the trade is open.
There are also two different things hiding in the word leverage: the maximum your broker permits, and the leverage you actually use. An account with 30:1 available can be run at 2:1 if you size positions carefully. The cap is a permission, not an instruction.
Three ratios, one identical trade
Take a single trade worth £30,000 of notional exposure and look at what each ratio asks of you. At 5:1 you post £6,000 and keep £24,000 of your account free. At 10:1 you post £3,000. At 30:1 you post £1,000 and the remaining £29,000 of exposure is funded by the broker.
The position is the same in every case. The pounds per point are identical. What changes is how much of your account is committed, and therefore how much of your account is exposed to the next unexpected headline.
This is why traders who boast about high leverage are often telling you something they don't realise: the size of the trade relative to the account is what matters, and a high ratio quietly makes that size large.
Same profit, different pressure
Suppose the underlying moves 2% in your favour. On a £30,000 position you make £600. If it moves 2% against you, you lose £600. The market has no idea which leverage setting you chose.
Now compare that £600 with the money you tied up:
- At 5:1, £600 is a 10% return on £6,000 of margin — and a 10% hit if it goes the other way.
- At 10:1, £600 is 20% of £3,000.
- At 30:1, £600 is 60% of £1,000.
Same trade, same pounds, radically different consequences for the account. That is the whole story of leverage in one comparison.
Where the ratio bites: margin calls and close-outs
How much room the position really has
Because your margin is effectively your equity in the trade, the ratio also sets the distance between entry and wipeout. At 5:1 you have 20% of the position's value as equity, so a 20% adverse move would take you to zero. At 10:1 it's 10%. At 30:1 it's around 3.3%.
Those figures flatter reality. Brokers hold a maintenance margin — a minimum equity level, usually expressed as a percentage of the position — and will issue a margin call, then close positions, well before equity reaches zero. Add financing charges on anything held overnight, spreads on entry and exit, and the practical buffer is narrower than the headline number suggests.
Ordinary market behaviour supplies the rest. A 3% move in a major index or currency pair is unremarkable. It can happen in an afternoon, and it can happen while you are asleep or away from the screen. At 30:1, a move that a 5:1 trader absorbs with a shrug can end the position.
Risk of ruin is arithmetic, not attitude
Risk of ruin sounds dramatic, but it is simply the probability that a run of losses takes your account below the level at which you can keep trading. Leverage feeds it directly. At 30:1, two or three adverse moves of a percent or two each — entirely ordinary for a volatile instrument — can remove most of your equity. At 5:1, the same sequence leaves you bruised but solvent.
Gaps and slippage make this worse. A stop order is an instruction, not a guarantee. When markets jump, your order fills at the next available price, which may be some distance from the level you chose. The higher the leverage, the less room there is between a normal fill and a ruinous one.
Choosing a ratio that matches the trade
Higher leverage isn't automatically wrong. It's wrong for particular jobs. Work through these questions before you decide how much of your cap to use:
- How volatile is the instrument? A ratio that feels comfortable on a large index may be reckless on a single small-cap share.
- How long will you hold? Overnight and weekend positions carry gap risk plus financing costs that eat into thin margins.
- How many positions are open? Four correlated trades are one large trade wearing four hats.
- What do costs add? Spread, commission and daily financing all come out of the same pot as your margin.
- How would you actually react to a 25% drawdown? Answer honestly; sizing should reflect the trader you are, not the one you'd like to be.
Check your own account too. Leverage caps differ by regulator, by broker and by product, and some instruments carry fixed margin requirements regardless of the headline ratio on offer.
Size the position first, then check the ratio
Here's a sequence that keeps leverage in its proper place. Decide how much of your account you are willing to lose on a single trade — 1% is a common starting point. Measure the distance from entry to your stop. Divide the first by the second and you have your position size.
An example: a £10,000 account, £100 of risk per trade, and a stop 2% away from entry. £100 divided by 0.02 gives £5,000 of notional exposure. At 5:1 that requires £1,000 of margin, or 10% of the account. At 30:1 it requires about £167. The ratio changed the deposit; it didn't change the sensible size.
Two habits are worth building on top of that. Keep a cash buffer so a margin call never forces your hand at the worst possible moment, and avoid running near your cap for the sake of it — headroom is what lets a good trade survive a bad afternoon.
Treat the ratio as the ceiling on what you can do, never as a target. If your position sizing suggests using less than a quarter of the leverage available to you, that is not timidity. It is the whole point. And if you are unsure how much risk your circumstances can absorb, speak to a regulated financial adviser before you commit capital.
