This Editorial Policy sets out how PhysicsTool chooses, sources, builds, tests and rechecks its physics calculators. One person, Manoj Meena, M.Sc. in Physics, carries out every step below and is accountable for every result on the site.
Effective date: October 3, 2026
Last updated: October 3, 2026
What Gets Built
PhysicsTool publishes a calculator only when the physics behind it is established and the formula can be traced to a published source. Mechanics, thermodynamics, electromagnetism, optics, fluid mechanics, astronomy, relativity and quantum physics all qualify.
A calculator is not built when its method has no accepted physical basis or when no citable source for the formula can be found. Tools that touch design or safety work are published with their limits stated, and they are never presented as a substitute for a code or a qualified professional.
Where Formulas and Data Come From
| Type of content | Accepted source |
|---|---|
| Fundamental constants | CODATA recommended values published by NIST |
| Units, prefixes and exact conversion factors | The SI Brochure from BIPM |
| Planet, Moon and Sun data | NASA NSSDCA fact sheets |
| Standard formulas and derivations | University physics and engineering textbooks |
| Empirical correlations and fitted equations | The original paper or an engineering handbook, quoted with its stated range of validity |
| Material and fluid properties | Published reference tables from standards bodies, handbooks or the manufacturer |
Other calculator websites, unsourced web pages and forum posts are not accepted as sources. They can show how a problem is usually framed, but a formula is used only after it has been found in one of the sources above.
How a Calculator Is Built and Tested
- The formula is read in its source, and its assumptions and range of validity are written down before any code exists.
- The calculation is coded in SI units, with every constant entered at the full precision its source gives.
- The calculator is run against worked examples with published answers, and a mismatch stops publication until the cause is found.
- Edge cases are tried, including zero, negative values, very large values and inputs outside the valid range of the formula.
- The same problem is entered in SI and in US customary units, and both answers must agree after conversion.
- The layout is checked on a narrow phone screen, since most visitors use a phone.
- The calculator is published together with its formula, its assumptions and a link to the source.
What Every Calculator Shows
Each calculator displays the equation it uses and defines every symbol with its unit. The assumptions are stated in plain words, such as no air resistance, an ideal gas or a thin lens, so you can judge whether the model fits your problem.
Each one also names its source with a link, shows the author, and carries the date it was last updated. A result is always shown with its unit and never as a bare number.
Precision and Rounding
Calculations run at full precision from input to result. Rounding is applied only to the number shown on screen, so a rounded intermediate value never feeds into a later step.
Displayed results are rounded to a sensible number of significant figures for the problem. Exact definitions are used wherever they exist, such as 1 inch = 25.4 mm, 1 pound = 0.45359237 kg and standard gravity = 9.80665 m/s².
Review by One Person
PhysicsTool has no second reviewer, and it would be misleading to suggest otherwise. The checks above exist to stand in for one. Every result must match an independent published answer before it goes live, not only my own working.
Readers are the second line of review. Every error report is checked against the source, and confirmed errors are fixed and recorded on the Corrections page.
When Calculators Are Rechecked
- When its source changes, for example a new CODATA adjustment of the constants or a new version of the SI Brochure.
- When a reader reports a result that looks wrong.
- When the calculator’s code is changed for any reason, in which case the full set of test cases is run again.
The “last updated” date on a calculator changes whenever its formula, constants, code or explanation is revised.
Independence
No company or person can pay for a calculator, a result, a mention or a link on PhysicsTool. Outside links are chosen because the source is authoritative for that formula, and none of them are paid or sponsored.
Questions About This Policy
Questions about a source, a test or a method can be sent to Manoj Meena through the contact page. More about who runs the site is on the About page.