Methodology
Calculations should be inspectable.
EasyTry separates fee rules, arithmetic, interface, and explanatory content so every estimate can be traced and tested.
Official sources first
Default rates come from platform-owned help centers or pricing pages. Competitor calculators are used for product research, never as the authority for a fee rule.
Versioned rules
Every production ruleset records its platform, market, category, effective period, source URL, and last verification date. If a rule cannot be confirmed, it is not silently used as a default.
Money and rounding
Core calculations use integer cents and basis points. Individual fee components are rounded to the nearest cent before totals are added. Reverse calculations search integer-cent values and verify the lowest supported amount that reaches the requested target.
Tests before publication
We test zero values, negative profit, threshold boundaries, progressive rate tiers, per-order fees, international exceptions, and reverse-price minimality. Display code does not own the fee formula.
Limits of an estimate
Marketplace statements can include taxes on fees, refunds, credits, optional services, negotiated rates, or account-specific adjustments that are not known to this calculator. EasyTry is a planning tool, not an invoice or accounting record.