The short answer
Decimals are the number of places after the decimal point a token can have. On chain, every balance is a whole number of the smallest unit; wallets divide it by 10 to the power of the decimals to show you the amount. A token with 6 decimals stores 1 token as 1,000,000 units. Decimals are set when the token is created and can never change.
| Decimals | Smallest unit | Maximum supply in whole tokens |
|---|---|---|
| 0 | 1 | about 18.4 quintillion |
| 6 | 0.000001 | about 18.4 trillion |
| 9 | 0.000000001 | about 18.4 billion |
What common tokens use
Every Pump.fun coin, USDC and USDT use 6 decimals. SOL uses 9. BONK uses 5. See decimals and supply explained for how to choose.
Why it matters
- Maximum supply. Supply is a 64-bit count of smallest units, so more decimals means a lower possible supply.
- Display. Wallets, explorers and DEXs read decimals from the mint. A mismatch between raw units and displayed tokens is a common source of mistakes in scripts.
- Pools and pricing. Most traded tokens use 6 or 9 decimals; 0 makes small trades impossible.
How we checked
Maximum supplies from the 64-bit amount field of the SPL Token and Token-2022 mint layout; decimals of USDC, USDT, SOL and BONK read from their mints on Solana mainnet on 3 November 2026.