Of course it changes.
If I have $1000 in my account, I can buy one contract, or two contracts. If I buy one, I use 200:1 leverage. If I buy two, I use 400:1 leverage.
Broker offers me permission to use leverage, but until I use it, there is no leverage.
It permit me to use from 1:1 to 400:1 leverage, whichever I choose.
So the leverage dose change as each trade occur, but the permission doesn't change.
https://en.wikipedia.org/wiki/Leverage_(finance)
In
finance,
leverage (or
gearing in the United Kingdom and Australia) is any technique involving using
debt (borrowed funds) rather than fresh
equity (value of owned assets minus liabilities) in the purchase of an asset, with the expectation that the after-tax profit to equity holders from the transaction will exceed the borrowing cost, frequently by several multiples — hence the provenance of the word from the effect of a
lever in physics, a simple machine which amplifies the application of a comparatively small input force into a correspondingly greater output force. Normally, the lender will set a limit on how much risk it is prepared to take and will set a limit on how much leverage it will permit, and would require the acquired asset to be provided as collateral
security for the
loan.
As you can read, leverage is the amount of debt you borrow to purchase an asset. If no purchase happen, there is no leverage.
What broker offers you is "how much leverage it will permit". it is the permission that doesn't change.
Who decides leverage? Brokers? Joke.
Only traders can decide how much money they want to borrow.
Brokers decide permission.
Traders decide actual leverage they want to use, which is the same as what amount of fund they want to borrow.
It is like you borrow from credit card.
Card limit=leverage permission broker offer
Each transaction that you borrow from your credit card=actual leverage you choose for each trade
The permission to use leverage doesn't change, but the actual leverage you use change all the way.