The full calculator library: 17 categories, 206 tools, formula shown
Every tool here is a calculator with formula shown: the working, the assumptions and dated sources sit under the result. Calculations run in your browser. No account, no paywall, no email wall before the answer.
How a tool works
Four steps from your question to a number you can check
The same pattern runs on all 206 tools, whether you are sizing a slab or working out take home pay in Australia.
Search or open a category
Type what you need, or pick one of the 17 categories further down this page. Everything is public. Nothing is held back behind a sign-up.
Enter the numbers you have
Inputs are the figures you already know: a loan amount, a paddock size, a payslip line. The sums run in your browser, so nothing is sent to us while you type.
Read the result, then the working
Under every answer sits the formula, the assumptions it used, and dated sources where a rate or rule comes from an issuing body. AU tax, super and study loan figures are reviewed each July.
Share the worked result as a URL
After you press Calculate, your inputs sit in the query string, so the whole worked example can go to a client, a builder or a classmate. Nothing is stored on our server from that step beyond what the URL itself carries.
03
How we work
A clear path from first conversation to finished work.
Australian tax and money calculators
Eighteen australian-finance tools covering super, HECS-HELP, take-home pay and stamp duty, with the figures and their review dates shown on each calculator page. Reviewed each July. General information only, not tax or financial advice.
Finance and loan calculators
Thirty-eight finance tools for loans, mortgages, compound interest and debt payoff. Each one shows the formula and the assumptions behind the result, so the working can be checked rather than taken on trust.
Health and fitness calculators
Twenty-four health tools including BMI, TDEE, calories and macros, reviewed when the issuing body updates its guidance. General information only, not medical advice.
Trade, construction and farming calculators
Thirteen trade-construction tools and nineteen farming tools for concrete, load, stairs and agricultural quantities. Useful for estimating, not a substitute for engineering sign-off.
A working reference library, not a lead-generation funnel.
17 categories, 206 tools
Every category, with counts, and every calculator with formula shown
Counts are live. Where a tool depends on a jurisdiction, the region is marked on the tool page and the figures carry their review date.
Everyday
Percentage and tip tools plus the quick sums you do most days. The working stays on screen, so you can check it before you act on it.
Finance
The biggest set: loans, mortgage repayments, compound interest, debt payoff and home affordability. Every result names its formula and its assumptions.
Australian finance
AU only. Super, HECS-HELP, take home pay and stamp duty. Rates and thresholds live on each calculator page with the date they were last reviewed.
Health and fitness
BMI, TDEE, calories and macros, reviewed when the issuing body updates its guidance. General information only, not medical advice.
Education
Two study tools, including the GPA calculator, with the grade maths written out rather than hidden.
Home and garden
Eleven tools for measuring up a room, a bed or a job around the house before you buy materials.
Farming
Nineteen tools for agricultural quantities and paddock maths. Good for estimating, not a substitute for professional sign-off.
Auto and travel
Four tools for trip and running-cost maths, with the conversion shown next to the answer.
Trade and construction
Concrete, load and stairs among thirteen tools. Useful for estimating quantities, not a substitute for engineering sign-off.
05 — Common questions
What the library does, and what it deliberately doesn't
The questions we get most about the tools, the numbers you type and the limits of a general-purpose calculator.
Frequently Asked Questions
- Is the whole library free?
- Yes. All 206 calculators, the 17 category pages, the A-Z listing and the search are free to use with no account and no paywall. If that ever changed, it would be stated on the About page first.
- Do you store the numbers I type in?
- The calculation runs in your browser, so your inputs are not sent to us to get a result. When you press Calculate, the inputs are written into the page URL so you can share the worked example. Nothing is stored on our server from that step beyond what the URL itself carries.
- Can I get tax, financial or medical advice from these tools?
- No. The money, health, legal and employment tools are general information only. They are not financial, tax, medical, legal or engineering advice, and we cannot advise on individual circumstances. Trade and farming results are for estimating and do not replace engineering sign-off.
- How current are the Australian figures?
- AU tax, super and study loan tools are reviewed each July. US federal tools are reviewed when inflation adjustments publish, health tools when the issuing body updates its guidance, and everything else at least annually. The figures and their review date sit on the calculator page, not in marketing copy.
- I think a result is wrong. What do I do?
- Send it through the contact form with the calculator name or link, the result you got, the result you expected, and a source if you have one. Corrections are made as a code change plus a test, so the same mistake cannot come back.
- Which jurisdiction does a tool use?
- Anything that depends on local rules is labelled by region: AU, US, UK or global. Super, HECS-HELP, stamp duty and Fair Work entitlement tools are AU. If a tool carries no region badge, the maths is the same anywhere.
Start with a tool, or start with the theory
There are 27 guides and 10 articles that explain the maths behind these tools, so you can learn the method and then run your own numbers. If a result looks off, tell us and we'll fix the code.