How to calculate it
You do not need a buy price to estimate a percentage move: multiply your capital by the change to get the profit, and by (1 + change) to get the resulting value.
If you know the current price, you can also derive the target price: target price = current price × (1 + change).
Comparison across capital levels
100 USDT at +20% → +20 USDT, position 120 USDT.
1,000 USDT at +20% → +200 USDT, position 1,200 USDT.
10,000 USDT at +20% → +2,000 USDT, position 12,000 USDT.
Notes
Fees are excluded above. Including a fee on both sides makes the realised return slightly below 20% — the smaller the move, the larger the fee drag.
With leverage the P&L is multiplied and liquidation risk appears. That requires contract-specific math, not the spot formula.
FAQ
How many dollars is a 20% BTC move?
It depends on the current price: 20% is 0.2 × current price. At 60,000 USDT, that is a 12,000 USDT move to 72,000 USDT.
Why does the result differ from the profit calculator?
This price-change tool excludes fees by default, while the profit calculator charges your fee rate on both the buy and the sell. Different conventions.