Methodology

Document processing

PDF to JPG renders selected static PDF pages as JPG or PNG images at an explicit resolution. Actual output previews, source page numbers and visible pixel dimensions help you inspect the export. PNG can preserve unpainted background transparency; JPG uses white. Images lose the searchable text and interaction of the original PDF.

JPG to PDF arranges images into paper-sized or image-sized pages, with explicit margins, orientation and optional smaller-file resampling. Independent synthetic images and exported-file checks cover layout, EXIF orientation, transparency and rendered appearance. It does not perform OCR.

Merge PDF structurally copies selected static pages in the displayed file order, with explicit page selection and rotation. Independent synthetic source PDFs and exported-file checks verify page counts, order, dimensions, text and rendered appearance. The supported files and features not preserved are explained on the tool page. It is not an archival, redaction or accessibility certification service.

Start with a defined question

Every calculator uses an explicit model: which figures belong in the calculation, which period they cover, how the answer is worked out and what it leaves out. The relevant formulas, assumptions and limits are published with the tool.

External sources support definitions where relevant. Our own choices, such as the timing of a cash scenario or how a minimum price rounds to cents, are described as model choices. A cited source does not endorse this site or its implementation.

The same inputs follow the same rules

Calculation rules are implemented separately from the interface. The same valid inputs produce the same result. Money uses whole minor units, such as cents, or exact ratios of those units, with explicit rounding and supported limits rather than hidden adjustments.

Currency symbols are display conventions; no currency conversion is performed. Use consistent currencies and periods. If a percentage is undefined or a projection reaches its limit, the tool explains that boundary instead of inventing an answer.

Check the examples and the boundaries

Automated checks compare results with independently specified expected examples, including zero values, undefined states, rounding boundaries and large supported inputs. Cash Runway also has a separately calculated monthly reference fixture. Browser checks cover interaction, responsive layout and accessibility.

Tests help detect errors and prevent known mistakes from returning. They cannot guarantee that every defect is found, establish forecasting accuracy or replace independent professional review. Engineering validation is not an audit or accounting certification.

AI assistance and responsibility

We use AI-assisted tools in research, development, drafting and testing workflows. AI output is not treated as a source: external definitions are linked where applicable, calculation rules are specified, and important examples and boundaries are checked.

Responsibility for what is published remains with BiznTools. We do not claim that these workflows provide independent human expert review. The published assumptions and examples let you check and challenge a result.

Review dates and corrections

A calculation-review date refers to an actual review of that model and its behavior. It is not refreshed simply because the site is deployed or its appearance changes. Source checks are recorded separately; any future time-sensitive rule must identify the period and source it relies on.

The Corrections page explains what makes a useful report and how issues are investigated. A material correction should identify what was wrong, the affected behavior and when it was corrected.