Direct answer
To calculate forex price moves using ask price, take the change in the pair’s quoted ask price between two moments. The simplest measure is a difference: the later ask price minus the earlier ask price. If you need the move in pips, convert that price difference into pip units using the pip size for the quoted currency pair.
This gives you a historical move for the chosen time window. It does not predict future movement, and it depends on consistent inputs (same pair, same quoting convention, and the same ask-price definition).
How to calculate the move (mechanics)
1) Define the two ask prices
Let:
- A₁ = the ask price at the start time
- A₂ = the ask price at the end time
- ΔA = the price move in quote-price units
Then:
- ΔA = A₂ − A₁
If ΔA is positive, the ask price increased over the window; if negative, it decreased.
2) Convert to pips (if needed)
A pip is a standardized unit used to express forex price changes. The exact pip size depends on the market convention for the pair. In many common cases:
- For pairs quoted to 4 or 5 decimals, a pip is often the last decimal place (commonly 0.0001 for 4 decimals and 0.00001 for 5 decimals).
- For pairs quoted differently (for example, some JPY-related quotes), pip size conventions differ.
Use a general conversion:
- Pips = (A₂ − A₁) ÷ pip_size
To apply this reliably, you must use the pip size implied by the instrument’s quoting format you are using.
3) Simple percentage move (optional)
If you want a relative measure instead of an absolute one:
- Percent move = ((A₂ − A₁) ÷ A₁) × 100%
This expresses the same change as a proportion of the starting ask price.
Example and checks
Assume a quoted currency pair has ask prices:
- A₁ = 1.1000
- A₂ = 1.1015
- Absolute move in price units:
- ΔA = 1.1015 − 1.1000 = 0.0015
- Convert to pips (illustration): If the pip size for this quote format is 0.0001, then:
- Pips = 0.0015 ÷ 0.0001 = 15 pips
Checks to apply when you calculate:
- Confirm both values are the same currency pair and same quoting direction.
- Confirm both are ask prices (not mid, bid, or last trade).
- Confirm the pip size matches the instrument’s quote decimals.
Relevant limitations and risks
- No real-time guarantee: This method computes a move for whatever two time points and ask prices you choose; it does not provide current or future values.
- Convention sensitivity: Pip conversion is only correct if you use the correct pip size for that pair’s quoting format.
- Timing matters: Using different timestamps can change the result, especially in fast-moving markets.
- No certainty about outcomes: A calculated past move describes history for the selected window; it does not imply likely future price behavior.
- Spread effects: Ask price already incorporates the spread component at that moment. If you compare ask-to-ask, you are consistently tracking the ask side, but the spread may vary across time windows.
Notes on interpretation
Ask-price moves are best interpreted as changes in the cost to buy at that quote moment, relative to another time. If you change the measurement basis (for example, using bid, mid, or last), you change what “price move” means. For independent verification, always restate the inputs (pair, ask definition, timestamps, and pip size) alongside the computed change.