Ratio (threshold math)

Governance thresholds, support percentages, and quorums are fractions, but Solidity has no fractions. OSx represents them as fixed-point integers with a shared base:

uint256 constant RATIO_BASE = 10 ** 6;   // 1_000_000 == 100%

So 500_000 means 50%, 750_000 means 75%. Every voting/approval threshold in the protocol (token voting, multisig, …) uses this unit, learn it once here.

Applying a ratio, and why it rounds up

_applyRatioCeiled(value, ratio);   // ceil(value * ratio / RATIO_BASE)

The ceiling is deliberate. When a ratio expresses a minimum requirement ("at least X% must approve"), rounding up ensures integer truncation never silently weakens it. Example: 50% of 3 members should require 2 approvals, not 1, floor division would wrongly allow passing with 1. Any plugin author computing a required count from a ratio should ceil, never floor. A ratio above RATIO_BASE reverts (RatioOutOfBounds).

Keep in mind

• Round up, never down, for a minimum requirement. Use _applyRatioCeiled; floor division silently weakens a threshold, letting a proposal pass with fewer approvals than the percentage implies.

See also

• Membership and the address list — the member count a ratio is applied to.
• Proposals — where thresholds decide hasSucceeded.