Calculators built by hand, that show their work.
I’m Umer Farooq, founder and developer of CalcsDone. I built this site to make practical calculations easier to use and easier to understand — with clear inputs, useful explanations, and transparent calculation methods that you can review instead of treating the result as a black box.
Browse the calculator library →Why I built this site
CalcsDone was created around a straightforward goal: make useful calculators easy to access while also giving visitors enough context to understand what a result means and how it was produced.
The library covers practical topics including finance, business, education, construction, health, science, sports, and everyday calculations. Calculator pages are designed to present the calculation method, important assumptions, explanatory context, relevant sources, and update information where those elements are useful to understanding the result.
Read our methodology →Privacy-conscious tools
Calculator inputs are designed to be processed in the browser rather than submitted as form data. Other site features, such as contact or review submissions, are covered separately in our Privacy Policy.
Practical results
Calculators are designed to return results quickly and present the output in a form that is useful for the task at hand.
Transparent methodology
Calculator pages document the formula or calculation method, important assumptions, and relevant sources where they materially help visitors understand or verify the result.
Free to use
CalcsDone calculators can be used without creating an account or purchasing a subscription.
Meet the founder
CalcsDone identifies the person responsible for building and maintaining the site so visitors can see who stands behind its content and contact the site when something needs attention.
Umer Farooq
Founder & developer, CalcsDone · About page updated
I design, develop, and maintain CalcsDone and oversee the ongoing review of its calculator pages. My role includes implementing calculation logic, improving usability, checking formulas and examples against appropriate references where available, and correcting pages when an issue is identified. CalcsDone is not a substitute for qualified professional advice, particularly for decisions involving health, finance, legal matters, or other high-impact topics.
The principles behind every calculator
These principles guide how calculator pages are researched, built, explained, and maintained across CalcsDone.
Clarity first
Plain language throughout — no jargon you have to decode before you can use a result.
Show the formula
Where a calculation is formula-based, the goal is to explain the underlying method and the important assumptions behind the result.
Privacy-conscious design
Calculator inputs are intended to stay within the calculation experience. Data intentionally submitted through other site features is handled according to the Privacy Policy.
Open to corrections
If you notice a calculation issue, unclear explanation, outdated reference, or other problem, you can report it through the contact page so it can be reviewed.
Same three steps, every time
Research the method
Identify the calculation method, definitions, assumptions, and suitable references for the topic. The appropriate source depends on the calculator and subject area.
Build and check it
Implement the calculation logic and check the behavior, units, edge cases, and worked examples where suitable reference values or examples are available.
Publish and maintain
Maintain explanations, sources, assumptions, accessibility, and calculation behavior as information changes or issues are identified. Reported errors and material changes are reviewed for correction or update.
How corrections and updates are handled
Calculator pages can change when a formula, rule, source, implementation detail, or explanation needs correction. Where a topic depends on changing rates, standards, guidance, or policies, the page should identify the relevant assumptions or reference material rather than imply that one result applies universally.
Check the issue
Reported problems are reviewed against the calculator logic, worked examples, and relevant source material.
Correct the page
When a material problem is confirmed, the calculation, explanation, source, or limitation is updated as appropriate.
Keep limits visible
Higher-impact calculators retain topic-specific limitations so an estimate is not presented as professional advice or an official determination.
Useful calculations, with clear limits
Calculator results depend on the information entered and on the assumptions built into a particular method. Some topics also involve standards, rates, guidance, or rules that can change over time.
For high-impact decisions involving health, finance, legal matters, or safety, treat calculator results as informational estimates and verify important decisions with an appropriately qualified professional or authoritative source.
Found an error?
Send the calculator URL and describe what appears incorrect so the issue can be reviewed.
Need more context?
Our Privacy Policy and Disclaimer explain how site features, submitted information, and calculator results should be understood.
Have a calculator in mind?
Suggest a useful calculator, report an issue, or tell me where an existing page could be clearer.