Key takeaways
- Planomy's projection engine runs in your browser, not on a server, so the arithmetic never needs a round trip.
- After the first visit the app installs to your device and keeps working with no connection — you can add it to a home screen or dock and open it like any other app.
- Your plan lives in your browser's storage on that device, so it is there whether or not the network is.
- What genuinely needs a connection: the first load, the AI assistant, bank sync, cloud sync and sharing, and refreshing the published tax dataset. Everything else does not.
- Tax brackets ship with the app as a bundled dataset and are upgraded from a published file when you are online, so an offline projection still uses real brackets rather than failing.
Why almost nothing in this category works offline
It is an architectural consequence, not laziness. If the projection is calculated on a server and your plan is stored in a database behind an account, then absolutely everything — including looking at a chart you generated last week — requires a request to that server. No connection, no product. Aggregation dashboards have it worse still: their core value is a live feed from your institutions, which is definitionally online.
That architecture is a fine choice with real benefits: it makes cross-device sync trivial and lets the vendor ship changes instantly. It just means the tool is unusable on a plane.
What makes a planner work offline
Three properties have to hold at once, and Planomy holds all three.
1. The engine runs on your device
Every projection — year-by-year balances, federal and state tax, Social Security, Medicare and IRMAA, RMDs, Monte Carlo across up to 10,000 trials, and the historical backtest over rolling windows from 1928 to 2024 — is computed in your browser. Monte Carlo runs in a background worker so a large pass does not freeze the page. None of it calls out to a server.
2. The app itself is cached on your device
On its first load in a modern browser, Planomy registers a service worker that keeps a copy of the application on your device. On later visits the app opens from that copy. You can also install it — "Add to Home Screen" on a phone, or the install action in a desktop browser — and launch it as a standalone window.
3. Your data is already local
The plan is written to your browser's storage on that device, so there is nothing to fetch. This is the same property that lets the planner work with no account at all; offline capability is the second thing you get from it.
What still needs a connection — and what doesn't
| Capability | Works offline | Notes |
|---|---|---|
| Year-by-year projections and charts | Yes | Computed in your browser |
| Federal and state tax, RMDs, IRMAA | Yes | Brackets ship bundled with the app |
| Monte Carlo and historical backtest | Yes | Runs in a local background worker |
| Scenarios, life events, goals, budgeting | Yes | All local |
| Editing and saving your plan | Yes | Written to on-device storage |
| Downloading a plan export | Yes | The file is generated locally |
| The very first load | No | You have to download the app once |
| Refreshing the published tax dataset | No | Falls back to the bundled copy |
| AI plan assistant | No | The model runs remotely |
| Bank sync, cloud sync, sharing | No | All are network features by definition |
Who this actually matters for
- People who plan on planes and trains. Long-haul flights are when a lot of people finally sit down with this stuff.
- Rural and intermittent connections. A tool that half-loads is worse than one that just opens.
- Anyone who dislikes their financial data being a network round trip. Offline capability and privacy come from the same architecture here.
- People who want the plan to outlive the vendor. An exported plan file and a local copy do not stop working if a company does.
The costs of offline, stated plainly
Every one of these is the mirror image of a benefit above. Offline capability is not free; it is bought with exactly these four things, and if any of them matters more to you than working on a plane, a cloud planner is the better buy.
- The plan is only as safe as the device. This is the big one, and it is not a caveat — it is the deal. Local storage means clearing your browser data, losing the laptop or wiping the phone takes the plan with it. There is no server-side copy to restore from, because not having one is the entire point. Two mitigations exist — download a plan file, or use a free account that syncs one plan — and both are things you have to remember to do. An offline-capable tool cannot protect you from this; only the habit can.
- Nothing updates itself. No market-price feed and no holdings feed. Balances are what you type, or what a Plaid connection imports on Plus — and bank sync is, obviously, one of the features that needs the network. A planner that works offline is a planner whose numbers you maintain by hand.
- The tax dataset refreshes online, not off. Federal brackets ship as a dated, versioned data file rather than as constants in the code, which is what lets them be corrected without shipping a new build — but picking up a corrected file needs a connection. Offline you are running whatever version was cached on your last online visit. It will not go stale mid-flight, and it will not quietly update either.
- Anything genuinely server-side stays unavailable. The AI plan assistant runs on a server and cannot answer with the network off. Neither can plan sharing, cloud sync or bank sync. Offline covers the whole projection — it does not cover the features that are, by definition, someone else's computer.
Two further limits unrelated to connectivity, so you do not discover them later: Planomy sells no advice and has no advisers attached to it, and the tax engine is US-only — federal brackets, state income tax, Social Security, Medicare, IRMAA and RMDs.
One more, specific to this page: if you want the plan on three devices without thinking about it, local-first is working against you. That is exactly what an account is for, and a free account syncing one plan may be all you need.
Try it, then turn your Wi-Fi off
It is a thirty-second test. Open the planner, build a rough plan, install it if your browser offers to, then disconnect and reload. The projection will still be there. While you are at it, the sequence of returns risk guide pairs well with a long flight.
Frequently asked questions
Can a retirement planner really work without an internet connection?
Yes, if the projection engine runs in your browser and your plan is stored on your device. Planomy caches the application with a service worker on the first visit, so later visits open from that local copy and every projection, chart, Monte Carlo run and edit works with no connection. Server-based planners cannot do this, because the calculation itself lives on their servers.
Do I need to install anything?
No. It runs in a normal browser tab. You can optionally install it — Add to Home Screen on a phone, or the install action in a desktop browser — which gives you a standalone window and makes the offline behaviour more obvious, but nothing about the planning requires it.
Are the tax brackets still correct offline?
A versioned tax dataset is bundled into the app, so an offline projection uses real brackets rather than failing. A published file refreshes that dataset when you are online. If you have been offline for a long time, reconnect once so the data can update before you lean on the tax figures.
What happens to my plan if I clear my browser data?
It is deleted, because that is where it lives when you are not signed in. This is the genuine cost of the local-first model. Download a plan export after your first real session and keep it somewhere you back up, or create a free account so one plan is synced.
Does the AI assistant work offline?
No. The assistant sends your question to a model running remotely, so it needs a connection. Nothing else does — projections, taxes, Monte Carlo, scenarios and editing all keep working, and running out of assistant messages or connectivity never blocks the planner itself.
Open it once. It works from then on.
Planomy loads into your browser, keeps your plan on your device, and keeps projecting whether or not you have a connection. Free, no account, nothing to install unless you want to.