About Us

Core Logic is a free online calculator platform. Everything here exists to answer one question quickly: what does the number actually come out to? No sign-up, no fees, no paywall, nothing to install — just the tool, the formula behind it, and the result.

Core Logic is an independent reference site written and maintained by Nathan Cole.

Who writes and maintains Core Logic

Core Logic is built and run by Nathan Cole, a developer who makes free reference tools for small businesses, freelancers, growers and students. Every calculator on the site is built from a published formula and checked against a second independent reference before it goes live. Where a result depends on a rate, a standard or a rule — a tax bracket, a freight-class threshold, an EPA emissions factor, a USDA irrigation figure — the source is named on the page so you can trace it yourself.

Nathan is not a licensed accountant, tax adviser, financial adviser, attorney, engineer or medical professional. The calculators here are estimation and planning tools. They are not professional advice and they are not a substitute for a qualified professional who knows your circumstances.

What is actually on the site

221 live calculators across ten categories. Every tool listed below exists, works, and is one click away — this is the real library, not a wish list.

Business & Trade (59 tools)

Margin, pricing, freight and landed-cost arithmetic for importers, sellers and small operators.

Finance & Tax (20 tools)

Take-home pay, VAT and tax-bracket estimators. These are estimation tools — they apply published rate tables to what you type in, and nothing more.

Agriculture (21 tools)

Irrigation, spacing, soil amendment and livestock timing calculators, built from published agronomic formulas and extension-service figures.

Environment (19 tools)

Carbon, emissions and resource-cost estimators for buildings, fleets and land use.

Education (20 tools)

Grade, ranking and mathematics calculators for students and teachers.

Lifestyle & Everyday (45 tools)

Kitchen, home and everyday measurement conversions that come up in the middle of a task.

Gaming & Virtual Economy (19 tools)

Calculators for players and designers working with in-game economies, drop rates and progression maths.

Automotive (9 tools)

Vehicle specification and running-cost arithmetic.

Health & Fitness (5 tools)

Pace, session-length and habit-cost arithmetic only. Core Logic deliberately does not offer diagnostic, dosage, treatment or condition-risk calculators — those questions belong with a qualified clinician, not a web form.

Legal Costs & Notice Periods (4 tools)

Date and cost arithmetic around contracts and screening fees. Core Logic does not provide legal documents, legal interpretation or legal advice.

How the calculators work

  • You supply the inputs. Each tool has labelled fields and a short note on what each input means. The result depends entirely on what you type in.
  • The formula is stated, not hidden. Most pages spell out the equation and the assumption behind each variable, so you can sanity-check the output by hand.
  • Results are reference estimates. They are rounded, simplified, and blind to anything the tool is not told — your jurisdiction, your contract, your local rates.
  • Nothing you enter is stored. All calculations run in your browser. Inputs are never transmitted, logged or saved on our servers.
  • Where a rate can change, we date it. Tax, fee and standard-dependent tools are reviewed whenever the underlying published figure changes.

What Core Logic is not

  • Not professional advice. Nothing on this site is accounting, tax, legal, financial, engineering or medical advice, and no calculator output creates a professional relationship of any kind.
  • Not a filing or submission service. We do not file returns, lodge documents, submit applications or act on your behalf.
  • Not a guarantee of an outcome. Real results depend on rules, contracts and conditions that no calculator can see.

If a decision matters and you will act on it — a tax position, a contract, a loan, a structural or safety question, anything about your health — take the number you got here to a licensed professional in your own jurisdiction and have it checked before you rely on it. That is exactly what these tools are for: getting you a fast first estimate, and telling you precisely what you asked for.

Corrections and updates

If a source has changed, a rate is out of date, or a tool gives you a number you believe is wrong, tell us through the contact page with the tool name and the inputs you used. Corrections take priority over new tools.

Ready to get your answer?

Browse the full library at all 221 tools, enter your own numbers, and see the working for yourself. The scope limits and disclaimers above are also set out in our Disclaimer, which records the date of the most recent review.

Last updated: September 14, 2026