Which FIRE calculators keep your data private?
You do not have to take anyone's word for it — including ours. Open your browser's developer tools, switch to the Network tab, and type your numbers into the calculator. If nothing new appears in that list, the arithmetic ran on your device and your figures did not leave it.
That check takes about thirty seconds, works on any tool, and is worth more than every privacy policy you will ever read, because it observes behaviour instead of promises.
Why we are not publishing a league table
The obvious article here would rank the well-known calculators by privacy. We are deliberately not doing that, for a reason worth stating plainly: a claim about someone else's product goes stale the moment they ship a change, and a stale accusation is worse than none. Tools add analytics, remove them, introduce accounts, change hosts. Anything we published today would be a snapshot presented as a fact.
There is a second reason, and it is the more interesting one. When we went looking (17 August 2026), several confident statements circulating about well-known planners' privacy behaviour could not be substantiated from those companies' own documentation — including a frequently repeated claim that one popular tool keeps your data in the browser. It may well be true. It was not something the vendor's pages said, and repeating it would have meant passing on a rumour with our name attached.
What does not go stale, and needs nobody's word, is the method. Below is how to check any tool — including this one — plus the vocabulary to interpret what you find.
The thirty-second check
- Open the calculator in a normal browser tab.
- Press F12 (or right-click → Inspect) and choose the Network tab.
- Click the clear button to empty the list, so you start from nothing.
- Now type your real figures — age, income, savings — and let the result update.
- Watch the list. Nothing new appearing means nothing was sent while you typed.
Two things that will confuse you the first time. Page load requests are normal and unavoidable — fonts, stylesheets, images. What matters is what happens after you clear the list and start entering figures. And a request appearing does not automatically mean your numbers were in it; it might be an analytics ping about the page view. Click the request and look at the payload if you want certainty.
The four levels of data handling
"Private" is not one thing. These are the four levels worth telling apart, from least to most exposure:
| Level | What it means | What you are trusting |
|---|---|---|
| 1. Computes locally, sends nothing | The arithmetic runs in your browser; your figures never travel | Nothing — you can verify it directly with the check above |
| 2. Computes locally, stores locally | Your plan is saved in the browser so it survives a reload, still without transmission | That the device is yours; browser storage is not encrypted by default |
| 3. Account-based, manual entry | You type your figures and the service stores them so they sync between devices | The provider's storage, staff access, retention policy and breach exposure |
| 4. Connects to your accounts | You link a real bank or brokerage, usually through an aggregator, and balances update automatically | All of level 3, plus the aggregator, plus a standing credential to your actual money |
None of these is wrong. Level 4 buys genuine convenience, and plenty of careful people accept the trade. The failure is not choosing level 4 — it is being at level 4 while believing you are at level 1.
Questions worth asking beyond the network check
- Does it work with the network off? Load the page, go offline, then use it. A tool that keeps working could not have been sending anything.
- Is there an export? A tool confident about your ownership of your data lets you take it out.
- What happens when you delete? "Delete account" and "delete my data" are not always the same operation.
- Who is the company, and how do they make money? A free tool with no visible revenue model is worth a second thought — especially in personal finance, where lead generation is lucrative.
- Does the policy mention selling or sharing with partners? Search the privacy page for "third part", "affiliate" and "sell".
Where Ember sits, in the same terms
It would be a poor article that applied this standard to everyone else and not to itself. Ember is two different tools, and they sit at different levels on purpose:
- The offline planner is level 1–2. Once the page has loaded it makes zero network requests — no analytics, no fonts fetched from anyone else, no calls home. Run the thirty-second check on it. This is also an automated test that runs on every change to the codebase, so it cannot quietly stop being true; the test asserts the browser recorded no resource requests at all.
- The optional account app is level 3. If you choose to sign in, your plan is stored so it can sync between your devices — encrypted in transit and at rest. That is a real trade and we are not going to describe it as anything else. You never have to use it; the planner works fully without an account, and Ember never asks to connect to a bank or brokerage.
Two surfaces, two honest answers. If a tool gives you one privacy answer for a product that has both shapes, that is itself a useful signal.
Check it yourself
Open the offline planner, press F12, and watch nothing happen.