Disclaimer

• The same decision can turn out differently. Two businesses can make the same cut, or two people the same purchase, and get different results. The site shows what follows from a set of figures. It cannot show what will happen.
• The answer is only as good as the figures. Most of what goes in is an estimate: a chance, a share, what something is worth to you. If the estimate is off, the answer is off by as much. Each answer shows its tipping point so you can see how far an estimate can be wrong before the answer changes.
• There are variables it cannot see. Every effort is made to show the effect of the things that are known to matter, and most calculators let you add your own costs and figures. Some things that matter will still be missing, and some cannot be put in numbers at all.
• The examples are illustrations. The figures in the worked examples were chosen to show how a sum behaves. They are not data about any real person, company, airline, employer or product, and they are not typical values you should assume.
• An average is not your outcome. Where a chance is involved, the result is an average over many tries. Any one case will land above or below it.
• Rates and rules change. Tax rates, mileage rates, fees and prices differ by place and by year. Where a figure of that kind is offered, check it against a current source. The tax and mileage figures assume the United States.

Nothing on this site is financial, investment, tax, accounting, legal, employment or other professional advice. It is general information and arithmetic. For a decision that matters, talk to someone qualified who knows your circumstances.

The site weighs decisions and processes. It is not meant for judging any one person, and it should not be used that way.

What it offers is a guide and not a rule. It does not say that any kind of decision is right or wrong. Many of its own examples come out in favour of the saving, the fee or the barrier being weighed.

This site is free to use and is provided as it is, with no warranty of any kind. The author accepts no responsibility for any decision made, action taken, or loss or damage arising from the use of the site or from reliance on anything it shows. You use it at your own risk, and the decisions you make remain your own.

The formulas are published and covered by automated tests, and care is taken to get them right. That is not a promise that they are free of error. If you find a mistake, please say so and it will be looked at.

The site may be changed, corrected or withdrawn at any time without notice.

• It never leaves your browser. Every sum is done on your own device by the page itself. Nothing you type into a calculator is sent to, stored on, or sold by any server, and there are no accounts and no cookies. Visits are counted, without cookies, by Cloudflare Web Analytics; what you type is never part of that.
• There is no login, because there is nothing to log in to. Each visit stands alone on your own computer or phone. The site does not know who you are and keeps no record of you.
• What is remembered is remembered by your device. The gig work log and a few of your last choices are kept in your browser's own storage so they are there next time. If your browser keeps a copy of a page, that copy is in your computer's cache, not on the server. Clearing the site's data in your browser removes all of it.
• The one exception is the feedback form. What you write there is sent to the author when you press Send, and only then.
• What a web host can see. As with any web page, the company that delivers the pages can see that a page was requested, and so can Google Fonts, which supplies the typefaces. Neither request contains anything you typed.

The full account is under Where your numbers go.

• There are no advertisements, nothing is for sale, and there are no paid or affiliate links.
• The site is not connected with any company, employer, airline, lender or product, named or implied.
• Links to other sites are given for reference. The author is not responsible for what is on them.

Last updated 6 October 2026.