At a glance
Killion is planning and simulation software with read-only account linking. Monarch Money is described below in its own terms. Where a figure is quoted it comes from the vendor's published pricing and was checked on the date shown.
| Killion | Monarch Money | |
|---|---|---|
| Individual price | $14/mo, or $11/mo billed annually ($132/yr). Max tier $24/mo or $19/mo annually. | Core $99.99/yr or $14.99/mo. Plus $199/yr (annual only). 7-day trial on both. |
| Free entry point | Free interactive demo with no account. Simulations run on a sample household. | 7-day free trial; no permanently free tier. |
| Budgeting | Category budgeting on manually entered cash and bank balances, feeding the projection directly. Automatic bank linking is paused during a provider move. | Full budgeting system with rules, categories, goals and shared household access. |
| Investment linking | Read-only brokerage and crypto linking via SnapTrade. Cash and bank balances are entered manually while automatic bank linking moves to a new provider. | Investment account linking for balances and holdings. |
| Long-horizon simulation | 1,000-path regime-switching Monte Carlo with fixed seeds, so a run reproduces. | Longer-term planning is available on the higher tier; not the product’s focus. |
| Historical backtesting | Historical backtesting against real market data going back to 1928. | Not offered. |
| Withdrawal rules | Fixed real dollar, fixed percentage, Guyton-Klinger guardrails, Vanguard dynamic spending, and endowment smoothing. | Not a decumulation tool. |
| Couples / shared access | Single-account today. | Shared household access is a headline feature. |
Monarch Money details checked on against the Monarch Money pricing. Vendors change prices; verify before deciding.
Two different jobs
Budgeting apps answer "where did it go". Simulators answer "where does this end up". Both matter, and the second one depends on the first: a retirement projection built on a guessed savings rate is a guess with extra steps.
Killion takes your income and spending from the Budget tab and feeds them straight into the projection, so the plan tracks what you actually earn and spend rather than a savings rate you guessed once. That is a smaller budgeting feature set than Monarch offers, deliberately — the budget exists to make the simulation honest.
Running both is reasonable
If you already run Monarch for household budgeting and it works, there is no reason to move. Killion is the tool you add when the question shifts from this month to the next forty years, or when you want to see what a bad first decade of retirement does to the plan.
Which one to choose
Choose Killion if
- The question you care about is whether the plan survives forty years, not whether groceries came in under budget.
- You want backtesting, sequence-risk stress tests and named withdrawal rules.
- You want spending to flow into a projection rather than only into a report.
Choose Monarch Money if
- You and a partner manage money together and need shared access.
- Category-level budget discipline is the actual goal.
- You want the most polished day-to-day money app in the category.