My goto for any kind of arbitrary precision math in JavaScript is https://github.com/MikeMcl/big.js https://github.com/MikeMcl/big.js As others have noted, if

My goto for any kind of arbitrary precision math in JavaScript is https://github.com/MikeMcl/big.js https://github.com/MikeMcl/big.js As others have noted, if you're doing any kind of math that involves floating point numbers and you will displaying them to a user, you'll almost certainly want something like this. While it's not specifically a "Money" class it can form an excellent base for one.