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ZBee vs ProjectionLab

Last reviewed: August 2026

ProjectionLab is the closest thing ZBee has to a philosophical cousin: both are built by small, independent teams, both take privacy seriously, and both refuse to become another sell-your-data finance site. The difference is the kind of tool each one is. ProjectionLab is a sandbox — you type in your finances and model any life scenario you can imagine, with some of the best charts in the category. ZBee is an instrument — it connects to your real brokerage accounts and measures one thing: the most you can safely spend.

The one-line version: ProjectionLab is for modeling the lives you might live; ZBee is for measuring the spending your actual accounts support.

  ZBee ProjectionLab
Where your data lives On your Mac — by design, not policy Your browser or their cloud (your choice)
Platform Native Mac app Web
Native iPhone app Free iPhone & iPad app — a private, on-device estimate No app — web/PWA
Uses your real accounts Yes — read-only, direct to your Mac No — you type them in
What linking brings in Your actual holdings — every position, live prices No linking
Core question Most you can safely spend Model any scenario
Yearly spending guidance
in retirement
Yes — this year's trigger points in dollars: the level below which the rules trim (and to what), and where a raise is earned. Published Guyton-Klinger rules you can verify by hand Modeled inside projections — no live yearly readout
Would it have survived
real market history?
Yes — automatically: your safe-spend number is replayed through every real market sequence since 1928 (1929, 1966, 1973 and all) and reported as "survived N of M," with any failing years named Historical backtest available — you set it up per scenario
Year-by-year tax detail
(you can audit)
Yes — federal, state, IRMAA, NIIT, RMDs, shown Yes
Roth-conversion optimizer No — by design (see below) Rule-based
Shows its methodology
& what it won't model
Yes — cited sources, published Partial
Price / year $99 $129

ProjectionLab's price and features as published July 2026; they change — check ProjectionLab for the current details. ZBee isn't affiliated with ProjectionLab.

Where ProjectionLab does more

Being straight about this: ProjectionLab lets you model open-ended what-if scenarios — career breaks, house purchases, alternate lives — with beautiful charts, and the FIRE community loves it for exactly that flexibility. Credit where due on privacy too: its option to keep data in your browser rather than its cloud is a genuinely privacy-respecting design, and rare in this category. If what you want is a rich sandbox for exploring futures, ProjectionLab is built for that, and it's a fine reason to pick it.

Where ZBee is different

The deepest difference is what the numbers are built on. ProjectionLab has no account linking — your plan rests on figures you type and retype as markets move. ZBee connects read-only to your brokerage and pulls every actual position at live prices, so the answer tracks what you really own without maintenance. The second difference is the kind of answer: a sandbox gives you outcomes for the scenarios you think to build; ZBee gives you a measured spending number with this year's trim-and-raise trigger points in dollars, and automatically replays that number through every real market sequence since 1928 — no scenario setup required. And ZBee is a native Mac app rather than a web app, with the platform look, feel, and offline independence that implies.

ZBee also deliberately has no optimizer of any kind. It measures what your current situation supports; recommending restructurings is advice territory it stays out of. The full comparison covers this line-drawing in detail.

Planned life events are inputs, not scenarios

A distinction that's easy to miss when weighing the two: most of what a near-retiree wants to "model" isn't an alternate life — it's the life they're already planning. Downsizing the house at 75, a gift to a child in 2028, a new roof, part-time work for the first few years, higher health or care costs late in the plan: in ZBee those are ordinary Money in / Money out rows in the one plan — an amount and the years it applies. The year-by-year table works out their consequences (taxes included), the spending chart shows a one-time expense standing out against the steady baseline, and the safe-spend number re-solves with them in.

What ZBee deliberately doesn't have is a scenario library — parallel alternate lives, career-break branches, a move-between-states planner. Exploring futures you may never choose is ProjectionLab's home turf. If an event is real enough to plan around, it belongs in the plan — and the decisions that remain genuinely open (when to retire, when to claim Social Security, what to leave behind) get their own side-by-side readout on ZBee's Trade-offs screen.

Which should you choose?

Choose ProjectionLab if you enjoy building and comparing life scenarios, want maximum modeling freedom, and don't mind keeping the inputs current by hand.
Choose ZBee if you want one trustworthy number measured from your actual accounts, kept current automatically, on your own machine. The two philosophies are different enough that trying both is cheap — ZBee's demo mode is free and needs no signup.

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