This page explains how FreeToolBank tools and guides are made: where the facts come from, how the numbers are checked, and what happens when something is wrong.
It describes what we actually do today, including the parts we haven’t got to yet. If you find a page that falls short of it, please tell us.
Who makes the tools
FreeToolBank is a small, independent site. We don’t have a panel of outside reviewers, and we don’t claim professional qualifications we haven’t got. Every tool is built and checked by the FreeToolBank team using the process below. Where a subject calls for a professional, such as tax, health or building work, the page says so.
How a tool is chosen and planned
Before any code is written, each tool gets a written plan. It records:
- What people searching for it are trying to do, and what the tools already available do and don’t do.
- Something specific the tool will add. “Cleaner” or “faster” isn’t enough on its own. For example, our Arkansas salary calculator checks the low-income tax rates on the state’s withholding form, and our PA Turnpike calculator adds up trips with several legs.
- The sources for every rule and figure it will use, with the date each was read.
- Whether those rules are current. A tax table from last year, or a format the platform has replaced, would be worse than no tool.
Some ideas are dropped at this stage, because a good free tool already exists and we can’t name anything we’d add. We’d rather have fewer tools that are worth using.
Where our information comes from
We go to the source that sets the rule, not to another calculator or summary of it. In practice that means:
- Government and official bodies for tax, pay, benefits and regulations. For example, the IRS for federal withholding, state revenue departments for state formulas, the Consumer Financial Protection Bureau and Fannie Mae for mortgage rules, and the PA Turnpike Commission for tolls.
- Published codes and standards for building and safety figures, such as the International Residential Code.
- Manufacturers’ own data for product figures, such as the yield of a bag of concrete.
- Exam boards and governing bodies for scoring rules and official notices.
- Exact definitions for units: an inch is exactly 2.54 cm, a US gallon exactly 231 cubic inches.
Each tool page lists its sources and the date they were read.
When there is no official source
Some things have no official figure. Trade values in a video game, for instance, are set by players, and lists disagree. In those cases we say so plainly, name each source and the date we read it, show where sources disagree, and let you type in your own figures. We don’t present an estimate as fact.
Prices are another case. Material and labor costs vary by area and season, so where a tool needs a price, the number filled in is a labelled example for you to replace with a real quote. We don’t call an example an average.
How we check the numbers
Every calculator is covered by automated tests, written alongside the tool and run before it goes live. Tools that share an engine, such as our AP score calculators, share its tests. The tests compare the tool’s results with figures worked out separately, not with the tool’s own output. Depending on the tool, those figures come from:
- Worked examples published by the source itself. Our Arkansas calculator reproduces the state’s own worked example to the cent.
- Printed tables from the source. The same calculator was compared with every cell of the state’s printed withholding table.
- Sums worked by hand, and known results from mathematics, such as how full a round tank on its side is at a quarter of its height.
- Edge cases: zero, negative and empty inputs, very large values, units that don’t match, and the boundaries between tax brackets.
On our newer tools, the tests also check every figure quoted in the page’s text and frequently asked questions, so the page can’t say one number while the tool gives another. We’re adding the same checks to older tools as we update them.
Before a tool is published we also use it in a real browser: entering a second set of values over the first, checking that error messages appear and old results disappear, and checking the page on a phone-sized screen and in dark mode. We have not yet tested every tool in every browser or with a screen reader, and we don’t claim to have. That work is ongoing.
For more on formulas, units, rounding and tax, see our calculator methodology.
How we write
- The answer first. Each page starts with a sentence saying what the tool does.
- Real examples. Worked examples use real numbers you can check.
- Plain limits. Each tool says what it can’t do, and when you should ask a professional.
- No copied text. We read other tools to see what’s missing, and write our own.
- No hidden selling. We don’t take payment to include or rank a product. If that ever changes, the page will say so where it happens.
Estimates, not advice
Our tools give estimates. A paycheck calculator estimates withholding; your return settles your tax. A loan calculator estimates a payment; your lender’s documents have the real figures. Health and building tools are for information and planning. None of them is legal, tax, medical, financial or engineering advice, and each page says so where it matters.
Keeping pages up to date
- Every tool page shows the date it was last updated.
- Yearly figures are updated when the new ones are published. Tax tables, toll schedules and exam curves change, usually once a year. The tool’s text names the year it covers.
- Dated data says how old it is. Where values change often, the tool shows the date they were read and warns you when they’re getting old.
- When we update a figure, the tests are updated with it, so an old number can’t linger in the text.
Corrections and feedback
If a result looks wrong, a rule has changed, or something is hard to use, email support@freetoolbank.com. It helps to include the page, what you entered, what you expected and, if you have it, the source that shows the right answer.
When a report is right, we fix the tool, add a test so the mistake can’t come back, and update the page’s date. We don’t hide a correction by quietly changing a number. If an error could have affected a decision, such as a wrong tax figure, we say on the page what changed.
Privacy
Our tools run in your browser, and what you type stays on your device. A few tools look something up only when you ask them to, and our privacy policy lists those.