UK100 Lot Size Calculator
Indices
UK100 is an index — this calculator uses its own real contract size and point value rather than a one-size-fits-all forex formula, since point value and typical price steps vary a lot between instrument types.
How do I calculate lot size for UK100?
Say a trader has a $10,000 account and decides to risk 2% of it on a UK100 short (sell) at 10,713.78, with a stop 64 points away at 10,777.78.
Rounded to a size a broker will actually accept, that's 2.35 lots — a $199.88 loss if the stop is hit.
Using the same 64-point stop, here's how that scales at two common risk levels on a $10,000 account:
- Conservative (1% risk): $100.00 at risk, 1.18 lots
- Balanced (2% risk): $200.00 at risk, 2.35 lots
These are illustrative figures at a fixed example balance and stop — the calculator above uses live prices and your own real inputs. The percentage-risk model itself follows the position-sizing approach popularized by Van Tharp in Trade Your Way to Financial Freedom, among the most widely cited references for treating position sizing as its own risk-management discipline.
What is a standard, mini, and micro lot on UK100?
At UK100's stored contract size (1 units per lot), a "mini" position (0.1 lots) and "micro" position (0.01 lots) scale the point value down by the same factor — $0.13 and $0.01 per point respectively. Useful for sizing a position precisely rather than rounding to a full lot.
When should I adjust my lot size for UK100?
Consider sizing down around high-impact news events or major session overlaps, when volatility and slippage risk increase — a stop that normally holds can be jumped past entirely in a fast move. That risk is higher for an index like this one, which can gap on economic data releases than for a typically calmer major forex pair.
What drives UK100 and how that shapes your lot size
The FTSE 100 tracks the 100 largest companies listed on the London Stock Exchange, many of which earn most of their revenue outside the UK. Oil, mining and banking stocks, global demand, and the strength of the pound drive it. It is most active from the London open; the cash market is closed in the Asian session, so overnight moves follow other markets.
The index is priced in pounds, so its dollar point value moves with GBP/USD, and a weaker pound tends to lift it because overseas earnings are worth more in pounds. Intraday stops of 30 to 60 points are common.
Worked example: sizing a UK100 buy on a $10,000 account
The figures below are invented for illustration and use a rounded reference price, not a live quote. Assume a $10,000 account risking 1% on one buy trade with a stop 40 points below the entry.
- Risk amount: $10,000 × 1% = $100.00.
- Entry 10,700.0, stop 10,660.0: the distance is 40.0 in price, which is 40 points (distance ÷ 1).
- Value of one point: 1 × 1 = 1 GBP per point for 1 lot; assuming 1 GBP = $1.32, that is $1.32.
- Risk per 1.00 lot: 40 × $1.32 = $52.80.
- Lots before rounding: $100.00 ÷ $52.80 = 1.8939.
- Rounded down to the 0.01 lot step: 1.89 lots.
- Check: 1.89 × 40 × $1.32 = $99.79, inside the $100 budget.
If price reaches the stop, the loss is $99.79, about 1% of the account. A target twice as far away, at 10,780.0 (80 points), would pay 1.89 × 80 × $1.32 = $199.58. If you widen the stop to 80 points, the same $100 budget gives 0.94 lots, because lot size shrinks as the stop widens.
Margin check and effective leverage for this UK100 trade
- Position value: 1.89 lot × 1 contract × 10,700.0 × 1.32 GBP-to-USD = $26,694.
- Margin at 1:200 (0.5%): $26,694 × 0.5% = $133.47.
- Effective leverage: $26,694 ÷ $10,000 = 2.7×.
The leverage ceiling your broker allows did not enter the lot-size calculation at all. The risk amount and the stop distance set the size, and leverage only decides how much margin that size locks up. The UK100 margin calculator shows how that requirement changes with your own leverage.
Common UK100 sizing mistakes
- Copying a lot size from another instrument. One point on UK100 is worth $1.32 per lot here, so a 40 point stop risks $52.80 per lot; a pair or index with a different value per point would risk a different amount for the same count.
- Miscounting the point. The index is priced in pounds, so its dollar point value moves with GBP/USD, and a weaker pound tends to lift it because overseas earnings are worth more in pounds.
- Ignoring the spread. Spreads are wider at the open and in Asian hours.
- Rounding up. Adding even one 0.01 lot step (1.90 lots) would risk $100.32, above the $100 you set.
Verify UK100 against your broker before trading
This page starts from a contract size of 1 and a value of $1.32 per point per lot, which are reference values. Brokers differ, so open the contract specification for UK100 in your platform and confirm the contract size, the minimum and maximum volume, and the lot step before you rely on any lot size. A wrong contract size is the most common reason a calculated size is rejected or risks more than expected. For background on the instrument, see the FTSE 100 on Wikipedia, and for the leverage concept see leverage in finance.
More tools for UK100
- See how much margin that position ties up with the UK100 margin calculator.
- Check what one point is worth per lot with the UK100 pip value calculator.
- Work out the result of a finished trade with the UK100 profit and loss calculator.
- Compare risk and reward before entering with the UK100 risk reward ratio calculator.
- Mark support and resistance from yesterday's range with the UK100 pivot points calculator.
- Compare a similar instrument: GBPUSD lot size calculator.
- Compare a similar instrument: DJ30 lot size calculator.
Conclusion
This math only holds if 1 units per lot and $1.33 per point are actually your own broker's real numbers for UK100 — every broker can quote contract specifications slightly differently. Always confirm your own platform's UK100 specification (right-click the symbol in Market Watch, then Specification) before trusting a suggested lot size for a real trade. See how lot size is calculated step-by-step for the general method, Wikipedia's entry on contracts for difference for how brokers structure these contracts, and real MT4 order-ticket screenshots at different leverage settings for further reading.
Contract specification
Point value and minimum lot step vary by broker on index/CFD instruments — a mismatch here is a common, avoidable cause of an unexpectedly large loss. Confirm this instrument's contract specification in your platform before sizing a real trade.
Frequently asked questions
Can I risk the same percentage on every instrument?
Yes, the risk percentage itself is a decision about your account and stays consistent — what changes between instruments is point value and typical volatility.
Is lot size the same as position size?
Yes — on this site the two terms are used interchangeably; both mean the number of lots to trade.
Does leverage change the UK100 lot size I should trade?
No. Position size comes from your risk amount and your stop distance; leverage only caps how large a position you are allowed to open. In the example above a 1:200 account locks up $133.47 of margin for a $26,694 UK100 position, an effective leverage of 2.7×, while the lot size was set entirely by the $100 risk and the 40 point stop.
How many lots of UK100 can I trade with $1,000 and 2% risk?
With a $1,000 account risking 2% ($20) and the same 40 point stop, the risk per lot is $52.80, so $20.00 ÷ $52.80 = 0.3788 lots, which rounds down to 0.37 lots.
What stop distance is typical for UK100?
Intraday stops of 30 to 60 points are common. At $1.32 per point per lot, each extra point of stop distance adds that amount of risk for every lot you trade, which is why a wider stop always means a smaller lot size.