The real meaning of Bitcoin's block reward

The thought behind the numbers

The reward miners get for adding a new block to the chain is cut in half every 210,000 Blocks (~4 years).

When Satoshi started the network in 2009, the reward was 50 bitcoin per block. That's how he amassed his fortune of over one million coins.

Three halvings occurred since then, and the block reward shrank each time:

50, 25, 12.5 and 6.25

The question is: Why did it start with 50? Why not 70 or 15?

It might seem arbitrary, but there's a reason behind it.

The block reward tells you how much of Bitcoin's supply is left to mine.

The first 210,000 blocks had a reward of 50 bitcoin. This means after block 210,000 is added to the chain, 50% of Bitcoin's supply is still untouched. Today's reward is 6,25 bitcoin which tells us only 6.25% of Bitcoin's supply is left to be mined when we reach the next halving (block 840,000).

Here's a visual representation: