Satoshi is simply a denomination, not a different currency.

1 BTC is comprised of 100000000 Satoshi, similarly to how 1 dollar is 100 cents.

To convert between them, all you need to do is multiply or divide by 10^8.

For example, 1 BTC is 10^8 * 1 Satoshi. Similarly, 10000 Satoshi is equivalent to 10000/10^8, or 0.0001 BTC.

1 bitcoin = 100 million satoshis