FIRE glossary
Ember Score
Ember Score is a single 0-100 composite - shown with a tier label from Spark to Roaring - that averages six separate plan-health signals into one number, from progress toward your FIRE number to how well diversified and Monte Carlo-resilient your plan is.
Six axes, one number
Ember Score averages six plan-health signals, each clamped to an integer between 0 and 100: pot (your projected pot as a percentage of your required pot, capped at 100), runway (whether you're on track to hit your target retirement age - 50 if exactly on time, +10 per year early, -10 per year late, or 0 if FIRE isn't reachable or you haven't set a target age), safety (your sustainable draw at retirement as a percentage of your planned annual spend), spread (a diversification score derived from a normalised Herfindahl-Hirschman Index across your asset classes - a single asset class scores 0, two or more evenly-weighted classes score close to 100), resilience (the percentage of your Monte Carlo simulation paths that don't run out of money), and income (pension, state pension and rental income once in payment, as a percentage of your spend). The composite is simply the rounded mean of those six - no axis is weighted more heavily than another.
Every axis traces to something you already see on the dashboard
None of the six numbers are computed specially for the score - they're the same figures already driving your FIRE number, sustainable draw and Monte Carlo results elsewhere on the dashboard, just reshaped into percentages and averaged. That means the score can't disagree with the rest of your plan: if your required pot, draw coverage or simulation results look a certain way on their own pages, the score reflects exactly that, and the ExplainPopover on the score shows all six inputs and the formula behind them.
What it deliberately leaves out
An equal-weighted mean of six things treats a plan that's excellent on five axes and weak on one the same as a plan that's mediocre across the board - the composite alone won't tell you which. There's no dedicated debt, liquidity, sequence-of-returns, or cost-of-living axis; those pressures only show up to the extent they've already moved one of the six inputs (typically safety or resilience). And the resilience axis is only as trustworthy as the Monte Carlo assumptions feeding it - a badly calibrated return or volatility assumption produces a badly calibrated score, not a warning that the assumption itself looks off.
Across borders
Ember Score has no country field of its own - it's a pure function over six percentages the dashboard hands it. Of those six, only two are wired to react to a tax-residency move: the pot axis compares your projected pot to your required pot, and the required pot is grossed up for the destination country's income tax on the taxable share of your withdrawals, so moving residency can shift the pot axis - and, because it also moves the age at which your pot crosses that same required-pot line, the runway axis - with your portfolio completely unchanged. The safety and income axes don't get the same treatment: they're built from the gross sustainable draw and gross, inflation-adjusted pension income, both of which the engine deliberately computes independent of where you live, so a move that would meaningfully change your net income in retirement won't show up in either axis on its own. Spread and resilience are the reliably country-agnostic pair - diversification and Monte Carlo survival don't reference tax residency at all.
Common questions
Why did my Ember Score drop even though my pot grew?
The composite is the mean of six independent axes, not just your pot's size. Your pot growing raises the pot axis, but the score can still fall if, say, your target retirement age moved closer without the fire-date moving with it (lowering the runway axis), or a re-run Monte Carlo simulation came back less favourable (lowering resilience). Check the ExplainPopover breakdown to see which axis actually moved.
Does the Ember Score account for my debts?
Not as a separate axis - there isn't a dedicated debt-load signal. Debt shows up indirectly: clearing a loan changes your sustainable draw at retirement, which feeds the safety axis, and it changes your pot's growth path, which feeds readiness. A large debt load can pull the score down through those two axes without ever being named as debt in the trace.
What do the tier names (Spark, Smouldering, Glowing, Blazing, Roaring) mean?
They're just labelled bands on the composite: Spark under 25, Smouldering under 45, Glowing under 65, Blazing under 85, Roaring 85 and above. The tier is presentation only - it doesn't feed back into any calculation, so two plans in the same tier can still look quite different axis by axis.
Related terms
See ember score in your numbers
The free calculator gives a rough estimate; the full planner models your actual accounts, pensions, residency moves and taxes — with the maths behind every figure shown.