About ApexConverter
We build the calculation layer that professionals rely on when the number actually matters — documented, auditable, and computed entirely on your own device.
1. Our Mission
ApexConverter exists to remove ambiguity from consequential arithmetic. A mortgage decision compounds over 360 months. A structural load calculation carries physical risk. A paediatric dose has no margin for error. Yet the majority of free calculators on the open web present a number with no formula, no source, no named reviewer, and no indication of when the underlying parameters were last verified.
We took the opposite position. Every one of our 1,000 engines publishes the closed-form formula it applies, defines each variable, works through a numeric example by hand, names the specialist who reviewed it, and states when it was last checked. If you cannot independently reproduce our output with a pencil, we consider the page incomplete.
2. The Zero-Server Client-Side Execution Model
This is the architectural commitment that defines the platform. Every calculator on ApexConverter is written in plain JavaScript that executes inside your browser tab. When you enter a salary, an outstanding loan balance, a body-fat measurement or a clinical value, that figure is held in your device's memory, computed locally, and discarded when you close the tab.
No transmission
Calculator inputs are never sent to our servers. There is no API endpoint receiving your numbers and no request body to intercept in transit.
No storage
We operate no database of user calculations. There is no record to subpoena, leak, or sell, because the record was never created.
No accounts
No sign-up, no email gate, no password to breach. Full functionality is available to anonymous visitors on first load.
Works offline
Once a tool page has loaded, it continues to calculate without any network connection, which is direct proof that no server round-trip occurs.
You can verify this yourself in about fifteen seconds: open any calculator, open your browser's developer tools, switch to the Network tab, and change your inputs. No requests will be issued. Our Security Policy documents the controls that protect this guarantee.
3. Editorial & Review Standards
Every calculator passes a five-stage gate before it is published, and re-enters the gate whenever its underlying standard or statutory parameters change.
| Stage | Requirement | Owner |
|---|---|---|
| 1. Sourcing | Formula traced to a primary standard, statute, or peer-reviewed publication — never a competitor page | Domain Lead |
| 2. Implementation | Double-precision engine written with explicit handling of edge cases and division-by-zero | Engineering |
| 3. Reconciliation | Output matched against an independent reference implementation across a bounded test matrix | QA Analyst |
| 4. Manual verification | At least one worked example computed by hand and published on the page | Domain Lead |
| 5. Annual review | Statutory parameters re-verified each fiscal year against the issuing authority | Editorial |
Where a calculation has legitimate methodological variants — body-fat estimation, for example, or goodwill valuation — we state which convention we implement and why, rather than silently selecting one.
4. The Team
Eighteen years across corporate treasury and institutional real-estate finance. Owns the finance, mortgage, tax and business verticals and authored the amortisation core.
Registered clinician and biostatistician. Reviews every health, chemistry and biology engine, with particular scrutiny applied to any dosing calculation.
Chartered structural engineer. Validates load, material take-off and mechanical tools against current design codes and published safety factors.
Owns the Vanilla JavaScript performance budget, accessibility conformance, and the client-side privacy architecture across all 1,000 pages.
5. Performance Engineering
Speed is a correctness issue, not a cosmetic one: a calculator that takes four seconds to become interactive has already failed the user who needed an answer during a phone call with their lender.
- No frameworks. No React, Angular, Vue or jQuery anywhere on the platform. Every engine is hand-written Vanilla JavaScript, typically under 6 KB before compression.
- Critical CSS inlined. Stylesheets are embedded in the document head, eliminating render-blocking network requests entirely.
- Zero third-party JavaScript in the critical rendering path.
- System font stack. No web-font downloads, therefore no layout shift from font swapping and no flash of invisible text.
- Reserved layout space. Output regions are dimensioned before results render, holding Cumulative Layout Shift at zero.
The standing target is 100/100 on Google PageSpeed Insights for both mobile and desktop, with Core Web Vitals in the green across the field data set.
6. Corrections & Contact
We publish mathematics, so we accept the obligation that comes with it. If you find an error, report it and we will fix it publicly.
apexconverter.praxiscalc@gmail.com
General enquiries & licensing
Partnerships, embedding and mediaContact page →
Frequently Asked Questions
5 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
Who is behind ApexConverter?
ApexConverter is operated by ApexConverter Quantitative Systems, a small specialist team of financial analysts, engineers, clinicians and front-end performance specialists. Every calculator is assigned a named reviewer with credentials in the relevant discipline, and that reviewer is displayed on the tool page.
How does ApexConverter make money if the tools are free?
Revenue comes exclusively from contextual display advertising served alongside content. We do not sell, rent, broker or share user data, and we do not operate a behavioural profiling business. Because computation is client-side, we do not possess the calculation data that would make such a business possible.
How are new calculators prioritised?
We rank candidate tools by three factors: aggregate search demand, the error cost of getting the calculation wrong manually, and whether existing free tools already document their methodology transparently. High-stakes and poorly-served calculations are built first.
What qualifies ApexConverter to publish financial and health calculations?
Each vertical is owned by a practitioner with domain credentials — CFA charterholders for finance, chartered engineers for structural and mechanical tools, and registered clinicians for health engines. No calculator ships without a documented formula source, a hand-verified worked example, and a named reviewer.
Can I report an error in a calculation?
Yes, and we treat it as a priority. Email apexconverter.praxiscalc@gmail.com with the tool URL, your inputs, the output received, and the output you expected. Verified mathematical errors are patched within 72 hours and the tool's revision history is updated accordingly.