Best practice for handling percentages

[abcoathup]

If you were were using SafeMath, then your calculations would all be in integers, so you would need to be aware of rounding issues.

There is a discussion on designing a fixed point math library for OpenZeppelin Contracts that I suggest reading:

Designing Fixed Point Math in OpenZeppelin Contracts

Due to popular demand (including @albertocuestacanada, @asselstine and @BrendanChou), we've been exploring the space of fixed-point math libraries to come up with a robust yet flexible design that is appropriate for most use cases. The current plan is to include such a library in the v3.1 release of OpenZeppelin Contracts, a couple weeks from now. Regarding scope, our initial thoughts are to limit support to add, sub, mul and div. Implementation of functions such as pow, sqrt or log is often he…

I also recommend watching Austin's video on Computing and accumulating interesting on chain:

Computing and Accumulating Interest On-Chain (common patterns and their properties)

[Computing and Accumulating Interest On-Chain] Computing and Accumulating Interest On-Chain (common patterns and their properties) Many DeFi projects need to compute interest on chain, and they often need to accumulate interest over several different user accounts at the same time. In this presentation we look at the challenges of computing compound interest on-chain, and the two main approaches that DeFi projects use to overcome them. We discuss the pros and cons of each. We also discuss th…