Numeraty Methodology

Last updated: February 27, 2026

Numeraty exists to help people make better decisions with clear, reproducible calculations. This page explains how we build calculators, where formulas come from, how we test changes, and what limitations users should keep in mind.

1. Scope and Purpose

Numeraty calculators are educational planning tools. They are designed to estimate outcomes quickly, compare scenarios, and surface tradeoffs. They are not financial, legal, tax, medical, or engineering advice.

If your decision has high legal or financial impact, verify outputs with official documents and a licensed professional.

2. Formula Selection

For each calculator, we prioritize formulas that are:

  • Standard in the domain (finance, lending, tax, health, engineering, conversion math)
  • Interpretable by non-specialists
  • Stable across common planning scenarios

When multiple conventions exist, we choose a default approach that is broadly recognized and document assumptions in field labels, helper text, or supporting copy.

3. Inputs, Defaults, and Assumptions

Default values are selected to provide a realistic starting point, not a recommended value for every user. Inputs are validated to reduce common errors (invalid ranges, impossible values, divide-by-zero conditions, and missing required fields).

Assumptions may include simplified tax handling, constant rates, or fixed contribution patterns. Real-world providers can produce different results due to underwriting rules, fees, penalties, and policy-specific logic.

4. Update and Review Process

We maintain calculators as versioned software and review updates when:

  • Users report unclear results or edge cases
  • We identify formula or UX issues
  • Regulations or market conventions materially change
  • We improve input handling, output clarity, or explanatory content

Each calculator page includes a review timestamp so users can see recency.

5. QA and Reliability Checks

Before release, we run a combination of:

  • Deterministic checks against known expected outputs
  • Edge-case validation for boundary inputs
  • Consistency checks for units and formatting
  • Build-time content/schema validation for metadata and structured content

Where practical, we compare outputs against independent references or hand-calculated samples.

6. Privacy and Data Handling

Core calculations run in the browser. Numeraty does not require user account creation for calculator use. For legal details, see our Privacy Policy and Terms of Service.

7. Known Limitations

All calculators are models. Outputs can deviate from real-world outcomes when conditions change or when institution-specific rules apply.

Common sources of variance include:

  • Regional taxes and fees
  • Credit score and risk-tier adjustments
  • Product-specific terms
  • Timing effects and compounding conventions
  • Rounding differences across systems

8. Feedback and Corrections

If you find an issue, ambiguous assumption, or missing use case, contact us at numeratyapp@gmail.com or via Contact. High-quality feedback helps us improve both accuracy and clarity.

Numeraty is developed and operated by Amrify LLC.

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