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.
Who Planomy is not for
Local-first has real costs, and they are the mirror image of its benefits. If any of the following describes you, a cloud planner is the better buy — and we would rather say so.
- You want balances and prices to update themselves. Planomy has no live market-price or holdings feed. Balances are what you enter, or what an optional bank connection imports. That is a deliberate local-first trade-off, and if you want a portfolio that refreshes on its own it is the wrong tool.
- You want a person to look at your plan. Planomy does not sell advice and has no advisors attached to it. If what you actually want is a fee-only CFP to review your situation, hire one — a projection is an input to that conversation, not a replacement for it.
- You are planning outside the US. The tax engine models US federal brackets, Social Security, Medicare and IRMAA, and RMDs. None of that transfers.
- You need exact state tax in every state. 29 states plus DC carry full progressive brackets; the rest are modelled at a flat effective rate. The app tells you which kind your state is using rather than hiding it, but if you live in a flat-rate-approximated state and the state bill is the crux of your decision, treat that line as an estimate.
- Day-to-day budgeting is the whole job. Planomy compares your actual spending against your plan, but it is a long-horizon planner first. If you want envelope budgeting, receipt splitting and bill reminders, a dedicated budgeting app will serve you better.
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.