Evm Token Decimals

If you've ever shipped a dashboard where USDC balances looked fine on Ethereum but were off by a factor of a million on Solana-bridged versions, this is for you. It walks through runtime decimal lookups, chain-aware caching, and safe normalization patterns in Python, TypeScript, and Solidity. The examples cover defensive fallbacks for non-standard tokens, normalization to 18-decimal WAD, and the critical rule of caching by chain ID plus address instead of symbol. It's a narrow skill but solves a class of bug that's silent until users notice their portfolio tracker is wildly wrong.

skills.sh installs: 5.4K
GitHub stars: 300.3K
last updated: Aug 21, 2026

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Install

$ npx -y skills add affaan-m/ecc --skill evm-token-decimals --agent claude-code

Installs into .claude/skills of the current project.

Files

EVM Token Decimals

Silent decimal mismatches are one of the easiest ways to ship balances or USD values that are off by orders of magnitude without throwing an error.

When to Use

Reading ERC-20 balances in Python, TypeScript, or Solidity
Calculating fiat values from on-chain balances
Comparing token amounts across multiple EVM chains
Handling bridged assets
Building portfolio trackers, bots, or aggregators

How It Works

Never assume stablecoins use the same decimals everywhere. Query decimals() at runtime, cache by (chain_id, token_address), and use decimal-safe math for value calculations.

Examples

Query decimals at runtime

from decimal import Decimal
from web3 import Web3

ERC20_ABI = [
    {"name": "decimals", "type": "function", "inputs": [],
     "outputs": [{"type": "uint8"}], "stateMutability": "view"},
    {"name": "balanceOf", "type": "function",
     "inputs": [{"name": "account", "type": "address"}],
     "outputs": [{"type": "uint256"}], "stateMutability": "view"},
]

SKILL.md on GitHub