Direct answer: inputs you need
To work out a lot size and pip value, you need to know (1) how big your position is, (2) what a “pip” means for the specific instrument, (3) the contract size that converts lots into units, and (4) the currency conversion path from the pip’s value currency into your account currency. In practice, you also need any variable exchange rates involved in conversions, and you must keep the units consistent (lots, base units, price decimals).
If you are trying to explain “lot size and pip value” to someone else, the minimum reliable input set is:
- Your position size expressed as lots (or directly in base units).
- The pair/instrument definition that determines the pip size.
- The contract size per 1 lot.
- The pip value currency implied by the pair.
- The account currency and the conversion rate(s) needed to express the pip value in that currency.
Mechanics and definitions: what each input is
1) Lot size (position size)
Lot size is your position size expressed in standard “lot” units rather than raw share/coin counts. Many forex calculations start by converting lots into base units using a known contract size per lot. If your input is already in base units, you can skip the conversion step, but you still need contract-size context to interpret how those units map to “1 pip.”
Stable mechanic: “Lot size → base units” is a unit conversion based on contract size.
2) Contract size per lot (units per lot)
A contract size tells you how many base units one lot represents for that instrument. This is a core input because pip value is ultimately a value of a price move per unit held.
Stable mechanic: base units per lot multiplied by position direction/size determines how much exposure you have.
3) Pip definition for the instrument (pip size)
A pip is a standardized price increment, but the standardized increment depends on the instrument’s quoting format. For many forex pairs, the pip is tied to a specific decimal place (often the 4th decimal in quotes, with special cases for instruments quoted differently). You must use the pip size that matches the instrument you are trading and the exact quoting convention your provider uses.
Stable mechanic: pip size is the smallest price increment you treat as 1 pip.
4) Pair orientation and the implied pip value currency
In forex pair quotes, one currency is the base currency and the other is the quote currency. The pip value currency depends on which side the pip move effectively “lands” on and how your exposure is measured (your position is in the base currency’s units, while the quote currency is involved in price). Therefore, you need to know:
- the base currency and quote currency for the pair, and
- which currency your pip value should be expressed in (usually your account currency).
Stable mechanic: pair orientation determines the currency that the pip move translates into before conversion.
5) Account currency (what currency you want pip value in)
Your pip value often needs to be expressed in your account currency. That means you need to know the account currency and whether it matches the pip value currency.
Stable mechanic: if account currency equals pip value currency, you may avoid conversion; otherwise you need conversion.
6) Exchange rate(s) for any conversions (variable inputs)
If your account currency differs from the pip value currency, you must convert. That requires one or more exchange rates. These rates are variable and change with market conditions.
Variable input: the conversion exchange rate(s) used at the time you compute or estimate pip value.
Evidence or example: assembling the inputs (assumptions made explicit)
Here is a framework example with clear assumptions, without assuming any live price data.
Assumptions (you must fill in the blanks):
- You trade a forex pair with known base currency and quote currency. 2) You know your position size as either lots or base units. 3) You know the pip size used for that pair (e. g. , 0. 0001 for the “standard” 4-decimal quote convention, if applicable). 4) You know the contract size per lot (units per lot). 5) You know your account currency.