Futures Calculator Stone: How to Estimate Profit

This futures calculator works out the profit or loss on a stone (a unit of weight) of a commodity futures contract. You enter the contract size, the number of contracts, the entry price, the exit price, and the price tick size, and it returns the total dollar gain or loss, the gain or loss per unit, and the number of ticks. The result helps you quickly see whether a trade meets your risk or reward target before you place it.

Formula

The core formula is straightforward:

Total Profit/Loss = (Exit Price – Entry Price) × Contract Size × Number of Contracts

Where:

• Exit Price – the price per stone when you close the position (in dollars)
• Entry Price – the price per stone when you open the position (in dollars)
• Contract Size – the number of stone units in one futures contract (e.g., 100 stone)
• Number of Contracts – how many contracts you traded

If the exit price is lower than the entry price, the result is negative, meaning a loss. The tick size is used to convert the price difference into ticks, which is how futures traders often measure moves.

Worked Example

Using the default values from the calculator above:

• Contract size = 100 stone
• Number of contracts = 1
• Entry price = $50.00 per stone
• Exit price = $55.00 per stone
• Tick size = $0.01

First, find the price difference:

$55.00 – $50.00 = $5.00 per stone

Then multiply by the contract size and number of contracts:

$5.00 × 100 stone × 1 contract = $500.00

So the total profit is $500.00. The profit per stone is $5.00, and the number of ticks is $5.00 / $0.01 = 500 ticks.

What Is a “Stone� in Futures Trading?

In commodity futures, a “stone� is a unit of weight equal to 14 pounds (about 6.35 kilograms). It is used primarily in the UK and Ireland for agricultural commodities like potatoes, wool, and some livestock. In the US, most futures contracts use pounds, hundredweight (cwt), or metric tons, but a few contracts—especially those traded on UK exchanges—still quote in stone. For example, a potato futures contract might be sized at 100 stone, meaning each contract covers 1,400 pounds of potatoes.

When you use a futures calculator with stone, you are working with the contract’s actual unit, so you don’t need to convert to pounds or kilograms yourself. The calculator simply uses the stone as the base unit for the price and the contract size.

How to Use the Calculator Correctly

To get an accurate result, you need to know three things:

1. The contract specification – check the exchange’s contract details for the exact size in stone (or convert from pounds if needed).
2. Your entry and exit prices – these are the actual prices you paid and received, not the current market price.
3. The tick size – the minimum price increment for that contract, which is also listed in the contract specs.

Once you have those, enter them into the calculator. The result is your gross profit or loss before commissions and fees. If you trade multiple contracts, enter the number of contracts to scale the result.

Common Mistakes and How to Avoid Them

• Mixing units – Make sure the contract size is in stone. If the spec says “100 hundredweight,â€� that’s not the same as 100 stone. Convert first.
• Forgetting the contract multiplier – Some contracts quote in stone but the price is per pound or per ton. Always verify the price unit.
• Using the wrong tick size – A tick might be $0.01, $0.10, or even $1.00 depending on the contract. Using the wrong tick size gives a wrong tick count.
• Ignoring commissions – The calculator gives gross profit. Subtract your broker’s commission and any exchange fees to get net profit.
• Rounding too early – When doing the math by hand, keep full precision until the final step to avoid rounding errors.

Limitations of the Formula

The formula assumes you enter and exit at exact prices, with no slippage. In real trading, your fill price may differ from the quoted price, especially in fast markets. The formula also ignores holding costs, such as storage or financing charges, which can affect the net result for physical commodities. Additionally, it does not account for margin requirements or leverage—those are separate calculations. For a complete risk assessment, you should also consider the maximum adverse price movement you are willing to tolerate.

Frequently Asked Questions

What is a stone in weight?

A stone is a unit of weight equal to 14 pounds (about 6.35 kilograms). It is used in the UK and Ireland for body weight and some agricultural commodities. In futures trading, a contract might specify a size in stone, such as 100 stone, which equals 1,400 pounds.

How do I convert stone to pounds for a futures contract?

Multiply the number of stone by 14. For example, 100 stone × 14 = 1,400 pounds. If the contract price is quoted per pound but the size is in stone, you would need to convert the size to pounds to get the total value.

Does the calculator work for any commodity?

Yes, as long as the contract size is expressed in stone and the prices are in the same currency. The calculator is unit-agnostic—it just multiplies the price difference by the size and number of contracts. You can use it for potatoes, wool, or any other stone-denominated contract.

What if I trade more than one contract?

Simply enter the number of contracts in the “Number of contracts� field. The calculator multiplies the per-contract profit or loss by that number, giving you the total for the entire position.

Is the result the same as my broker’s profit/loss?

Not exactly. The calculator gives the gross profit/loss based on price movement alone. Your broker will also deduct commissions, exchange fees, and possibly financing charges. The net figure will be slightly lower (or higher if you have rebates). Always check your broker’s statement for the final amount.

What is a tick in futures trading?

A tick is the smallest price increment a futures contract can move. For example, if the tick size is $0.01, the price can move from $50.00 to $50.01, but not to $50.005. The number of ticks is the price difference divided by the tick size, which is useful for calculating risk and setting stop-loss orders.

Related

• Increase Calculator UK: How to Work Out a Rise
• Increase Decrease Calculator: Percent Change
• EaseUS Data Recovery Wizard Free: What You Get

in cs | Contract size (stone) | stone | 100 | 0
in nc | Number of contracts | - | 1 | 1
in ep | Entry price (per stone) | $ | 50.00 | 0
in xp | Exit price (per stone) | $ | 55.00 | 0
in ts | Tick size (price) | $ | 0.01 | 0
out pl | Total profit/loss | $ | (xp - ep) * cs * nc | 2
out pps | Profit per stone | $ | xp - ep | 2
out ticks | Ticks moved | - | (xp - ep) / ts | 0