Decimal Calculator

Official Reference Table

Token / Chain	Standard Decimals	Authoritative Source
USDC	6	https://developers.circle.com/stablecoins/quickstart-transfer-10-usdc-on-chain
USDT (Ethereum)	6	https://etherscan.io/address/0xdac17f958d2ee523a2206206994597c13d831ec7#code
Toncoin (TON)	9	https://docs.ton.org/v3/guidelines/dapps/cookbook
Bitcoin (BTC)	8	https://developer.bitcoin.org/glossary.html#satoshis
Ether & most ERC-20s	18	https://docs.openzeppelin.com/contracts/5.x/erc20
ERC-20 spec	variable	https://eips.ethereum.org/EIPS/eip-20
Solana (SOL)	9	https://docs.solana.com/terminology#lamport

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FAQ — Decimals & Unit Conversion

1. What does the decimals field actually represent?

It defines how many base units compose one token unit.
If decimals = 18, an on-chain integer of 1_000_000_000_000_000_000 equals 1 token.
https://docs.openzeppelin.com/contracts/5.x/erc20

2. Why does USDC use only 6 decimals?

Circle chose 6 to mirror fiat “cents” UX and keep raw numbers small; every official USDC contract on every chain follows this.
https://developers.circle.com/stablecoins/quickstart-transfer-10-usdc-on-chain

3. Does USDC ever use 18 decimals?

Any 18-decimal variant is a bridged / wrapped token (e.g., Binance-Peg).
Always call the contract’s own decimals() before scaling.
https://developers.circle.com/stablecoins/quickstart-transfer-10-usdc-on-chain

4. I see both 6- and 18-decimal USDT contracts—what’s correct?

The canonical Ethereum USDT contract locks _decimals = 6.
18-decimal versions are redeployed bridge tokens; verify each chain’s contract.
https://etherscan.io/address/0xdac17f958d2ee523a2206206994597c13d831ec7#code

5. Can a token change its decimals after deployment?

No. decimals is an immutable constant in the bytecode.
Changing precision requires a brand-new contract.
https://eips.ethereum.org/EIPS/eip-20

6. What is the smallest transferable unit of Bitcoin, and how many decimals is that?

A satoshi – 1 BTC = 100 000 000 satoshis, i.e. 8 decimals.
https://developer.bitcoin.org/glossary.html#satoshis

7. How many decimals does Toncoin (TON) use, and what about Jettons?

Toncoin uses 9 decimals (1 TON = 1 000 000 000 nanoTON).
Most Jettons follow the same rule unless explicitly configured (e.g., 6 for TON-USDT).
https://docs.ton.org/v3/guidelines/dapps/cookbook

8. Where does the 9-decimal rule for Solana come from?

Solana’s smallest unit is a lamport; 1 SOL = 1 000 000 000 lamports (9 decimals).
https://docs.solana.com/terminology#lamport

9. How do I convert raw on-chain balances to human-readable numbers?

Use human = raw / 10**decimals.
For user input, multiply back (raw = human * 10**decimals).
Employ arbitrary-precision libraries—never JS Number for big values.
https://docs.openzeppelin.com/contracts/5.x/erc20

10. Is decimals mandatory in the ERC-20 standard?

No. It’s an optional function in EIP-20; clients must not assume it exists.
https://eips.ethereum.org/EIPS/eip-20

Tip for developers: cache each token’s decimals() value per network, and always verify bridged or wrapped assets individually to avoid scaling errors.