A gilt is quoted per £100 of nominal value, so the pounds it actually costs are the dirty price multiplied by the number of £100 units bought.
A price per hundred, not a price per gilt
A gilt's price is quoted per £100 of nominal value, not per unit and not in total. A clean price of 98.50 means £98.50 for every £100 of nominal the buyer takes. Hold £1,000 of nominal and the clean cost is ten times that, £985.00; hold £2,500 and it is twenty-five times it. The quoted figure is a rate, and the cost is that rate applied to the size of the holding.
That is why a gilt list can compare gilts of very different sizes on one price column. The price is stated on a common denominator — £100 of nominal — so a £500 million gilt and a £40 billion gilt are both quoted as a number near 100 rather than as a total that says nothing about value.
Nominal, units and the arithmetic
The nominal value of a holding is what the gilt will repay at maturity, and it is the figure the price is applied to. Every £100 of nominal is one unit for pricing purposes, so the sum is always the price multiplied by the nominal divided by one hundred. A holding of £2,500 nominal is 25 units; a holding of £10,000 nominal is 100 units. The nominal stays fixed for as long as the gilt is held; the price does not.
The nominal value is not the amount paid and not the amount the holding is worth at that date. It is the £100-per-unit promise the price is quoted against and the amount the gilt returns at redemption.
Rounding matters at scale. The price is quoted to a limited number of decimal places, and the cash figure is the price applied across every unit. A small difference in the quoted price is multiplied by the number of units, which is why a contract note and a list figure can differ by pence on a small holding and by pounds on a large one.
From clean price to cash
The cash a buyer pays is based on the dirty price, not the clean price. The clean price is the gilt's own value; the dirty price adds the accrued interest the seller has earned since the last coupon. On the conventional gilts list the clean price, the accrued interest and the dirty price all appear on the row, so the cash can be worked out without leaving the list.
Take an illustrative gilt quoted at 98.50 clean with 1.23 of accrued interest per £100 nominal. The dirty price is 99.73. On £1,000 nominal — ten units — the buyer pays ten times 99.73, or £997.30. Of that, £985.00 is the clean price for the gilt and £12.30 is the accrued interest taken over from the seller, which returns as part of the next coupon. Every figure is illustrative, not a quote from any gilt.
| Nominal held | Units of £100 | Clean cost at 98.50 | Accrued at 1.23 | Cash at 99.73 |
| £100 | 1 | £98.50 | £1.23 | £99.73 |
| £1,000 | 10 | £985.00 | £12.30 | £997.30 |
| £2,500 | 25 | £2,462.50 | £30.75 | £2,493.25 |
| £10,000 | 100 | £9,850.00 | £123.00 | £9,973.00 |
The table is one illustrative price applied to four holdings, and each column scales with the units. A reader who already knows the nominal they intend to buy can read the cash straight off the row they need, and a reader working from a cash budget can divide it by the dirty price and multiply by one hundred to reach the nominal instead.
Why the price is quoted clean
If gilts were quoted on the cash figure, every gilt's price would jump each day by the interest that had accrued since the last coupon, and two gilts would be priced on different points in their coupon cycles. Quoting the gilt itself, and showing the accrued interest separately, keeps the price comparable between gilts and across dates. The cash is then the sum of the two, which is why a buyer has to add them rather than read a single figure.
This is also why a holding's value on a statement can differ from its price on a list. The list shows the clean price; a valuation may use the dirty price, or the bid or offer side of the dealer quote rather than the mid. None of those is wrong, but each answers a different question, and knowing which is which is what makes a figure checkable.
Where the site works it out
The record-a-trade form takes the clean price and the accrued interest and derives the dirty price and the cash for the nominal entered, so a purchase can be costed before it is booked. The trade is then held against the settlement date on the profile, which is the date the accrued interest is measured to. A trade booked at one price and settled a day later carries one more day of accrual, and the form's figure moves with the date.
The habit worth forming is to convert to pounds at the last step, not the first. Read the price per £100, add the accrued per £100, and only then multiply by the units. Converting early rounds a per-£100 figure into pounds and then scales the rounding up by the holding, which is how a cash figure drifts from the price it came from.
Background, not advice
This guide explains how a gilt's quoted price becomes the pounds paid; it is general background, not investment, tax or legal advice for any reader's circumstances. Every figure above is illustrative with its inputs stated, and the price of a gilt moves, so the cash paid on one day will differ from the cash paid on another. The gilt's own record and the day's market data are the primary sources for a real price, accrued amount or cost.