How pip value is calculated for GBP/AUD (and across account currencies)

Direct answer

Pip value is the change in money (in your account currency) caused by a one-pip move in an FX position. For GBP/AUD, you can compute it from a base formula using the pip size, the trade size (lot/units), and the pair’s quotation, then convert into the account currency if needed.

How the calculation works

Define “pip” and “pip size”

A pip is a standardized price increment used to express FX price changes. In most FX quoting conventions, one pip is the smallest “fourth decimal place” move for pairs quoted to 4 decimals; for a pair quoted with five decimals, the smallest quoted tick may be smaller than a pip, but the common “pip” still corresponds to the 4-decimal step.

For formulas, you need a clear assumption:

Assume the broker/platform defines 1 pip = 0.0001 in the pair’s quote currency units (AUD) per one GBP.
If your platform defines differently, use its pip size instead.

Base pip value for the pair

Let:

Pair: GBP/AUD
Price: P = AUD per 1 GBP
Pip size: Δpip = 0.0001 (assumption)
Position size: N_GBP = number of GBP units controlled by the trade
Money impact before account-currency conversion: in AUD (because GBP/AUD is quoted in AUD)

A one-pip move changes the pair price by Δpip, so the approximate monetary change in the quote currency is:

Pip value (in AUD) = N_GBP × Δpip

This works because you can treat the trade’s notional in GBP as the “multiplier,” and the pip size as the “per-GPB” quote-currency increment.

If instead you use standard FX lots, you can map lot size to units:

For many retail FX contracts, 1 standard lot = 100,000 units of the base currency (here, GBP).
Then N_GBP = lot_size × 100,000 under that common assumption.

Material limitation: contracts vary. Some platforms use different lot definitions (e.g., mini/micro), and you must use the contract’s actual “units per lot” for GBP.

Convert pip value into the account currency

If your account currency is not AUD, convert the pip value from AUD.

Let:

Account currency: C
Conversion rate: R expressed as “C per AUD” or “AUD per C,” depending on how you look it up

Two common approaches (choose the one matching your rate quote direction):

If you have R = C per AUD, then:

Pip value (in C) = Pip value (in AUD) × R

If you have R = AUD per C, then:

Pip value (in C) = Pip value (in AUD) ÷ R

Assumption requirement: you must apply the conversion rate in the correct direction so you don’t invert the result.

Evidence or example (with explicit assumptions)

Assume:

1 pip for GBP/AUD is 0.0001
A position controls N_GBP = 100,000 GBP (interpreting 1 standard lot as 100,000 units)

Then:

Pip value (in AUD) = 100,000 × 0.0001 = 10 AUD

Now convert to another account currency:

If your account currency is USD and you obtain an FX rate R = USD per AUD, then Pip value (USD) = 10 × R.
If you obtain R = AUD per USD, then Pip value (USD) = 10 ÷ R.

Material limitation: this is a calculation of “price move impact per pip” using static pip size and notional. Real fills, spreads, and margin rules affect the actual cash result.

Limitations and common failure modes

Wrong pip size assumption: Some platforms or instruments may define pips using different decimal steps. Using 0.0001 when the platform uses a different definition leads to incorrect pip value.
Ignoring contract units: Pip value depends on how many base units the trade controls. If “1 lot” is not the standard 100,000 GBP, scale the notional accordingly.
Account-currency conversion direction error: Converting using the inverse of the rate is a frequent mistake. Always confirm whether the displayed conversion rate is “C per AUD” or “AUD per C.”
Market execution effects: Pip value is theoretical per price movement. Actual profit/loss depends on entry and exit prices, commissions, swap/rollover, and the broker’s pricing/fees.
Pip value sign vs. direction: Pip value magnitude is based on the pip size and position size; whether the P/L is positive or negative depends on long/short direction.