Bitcoin users usually wait about an hour before treating a payment as settled. Algorand ($ALGO) takes a different approach: payments are final as soon as they land in a block, which arrive roughly every 2.8 seconds.
Why Bitcoin payments wait for confirmations
On Bitcoin ($BTC), miners work at the same time, so conflicting versions of the chain can briefly form. According to a University of Maryland paper, the shorter branch is orphaned and any conflicting transactions are invalidated. This is the fork problem, and it means a payment on the losing side can be undone.
The risk of a reversal falls as more blocks are added on top. The same paper notes that a transaction with six confirmations is widely accepted as secure against double-spending. At about 10 minutes per block, researchers note that six confirmations take roughly an hour, which makes payments slow.
How Algorand avoids forks
Algorand is built to stop those splits from happening. It uses Pure Proof-of-Stake, in which, per Spark's Bitcoin vs Algorand comparison, a verifiable random function selects block proposers and committee members. Selection odds are proportional to the amount of ALGO held. Each new block goes to a vote by randomly chosen voters, and it needs more than two-thirds of the votes to pass.
Because the chain does not split, there is nothing to roll back. Finst's Algorand explainer says there is no need for several more blocks to be built on top of a block before it gets extra confirmation. Spark lists Algorand's finality as deterministic, in a single block, against Bitcoin's probabilistic finality of about 60 minutes for six confirmations.
The trade-off in a crisis
The design has a cost when things go wrong. If the network splits, or too many voters act dishonestly, Algorand stops producing blocks. Payments then wait until enough honest voters can reach each other again to restart. The protocol tolerates bad actors only while more than two-thirds of the stake is honest, according to Spark.
In short, Algorand trades continuous availability under extreme stress for speed and certainty in normal operation. Bitcoin makes the opposite trade: the chain keeps moving, but users wait for added confirmations before they can rely on a payment.
Sources:
Algorand: Pure Proof-of-Stake technology
Spark: Bitcoin vs Algorand
Liao and Katz: Incentivizing Double-Spend Collusion in Bitcoin