How SignLater’s tools and guides are built — the formulas, the sources, and the standards. If you can’t verify it, you shouldn’t trust it. So here’s everything.
Last updated: October 2026.
Calculator formulas (pp-1.1)
Our Payment Processing Cost Analyzer computes true monthly cost as:
True monthly cost = (volume × rate%) + (transactions × per-transaction fee) + monthly fees + (annual fees ÷ 12) + (equipment/lease costs ÷ months)
Effective rate = true monthly cost ÷ volume. This is the single number that lets you compare any two offers, and it’s the number salespeople least want you to compute.
What the formulas assume — and what they don’t:
- Constant ticket mix. Break-even projections assume your average transaction size stays roughly stable as volume changes. If your mix shifts dramatically, re-run the numbers.
- Illustrative vs. verified numbers. Worked examples in our guides are labeled either way. Verified numbers cite their source and verification date; illustrative numbers are realistic constructions for teaching the method.
- No hidden adjustments. The analyzer applies no vendor-specific tweaks, no sponsored weightings, no “adjustment factors.” Same inputs, same outputs, every time.
How guides are researched
- Primary sources first. Processor pricing pages, card-network rule documents, state statutes and attorney-general guidance. Secondary summaries are starting points, never citations of record.
- Rates verified at write time. Payment processing rates change. Every guide that cites a specific rate was verified against the provider’s published pricing in the month of publication, and the verification month is stated in the guide.
- Time-sensitive pages carry dates. Our surcharge law reference is stamped with its last-verification date, because that landscape moves with legislation and court decisions.
- No invented metrics. We don’t publish keyword difficulty scores, traffic estimates, or “average savings” figures we can’t source. If we don’t know, we say so.
Corrections
We correct errors publicly and promptly. Substantive corrections to numbers, formulas, or legal summaries are noted on the page with the correction date. Typos and formatting fixes aren’t logged — everything else is.
Spot something wrong? Contact us — corrections get priority handling.
What we don’t do
- We don’t accept payment for placement, ranking, or favorable coverage.
- We don’t publish sponsored guides disguised as editorial content.
- We don’t reuse other sites’ worked examples without doing the math ourselves. Every calculation on this site was computed here and can be reproduced from the inputs shown.
Related: About SignLater · How we make money