What's new: a 15%-50% custom percentage slider
Until now, the calculator's income-to-rent side worked from a single fixed 30% guideline, with 25%, 35%, and 40% shown alongside it purely as comparison reference points in the results and reference tables. That's still true — those four fixed figures haven't gone anywhere. What's changed is that there's now a fifth, fully adjustable option sitting right above the calculate button: a slider labeled "Custom rent-of-income percentage (sets your 'recommended' figure)," with a live percentage readout next to it and a hint showing the two ends of the range ("15% (very conservative)" to "50% (very stretched)").
In practice, this closes a gap that came up directly in an earlier post on this blog about picking a personal rent-to-income target: at the time, matching your own derived percentage to the calculator meant doing the multiplication by hand and comparing it to the nearest fixed preset. The slider removes that extra step — your own number is now the one the calculator reports back to you.
How to use it
- Step 1: Open the calculator and stay on the "Rent I can afford" tab (it's the default tab).
- Step 2: Enter your gross monthly income, or switch to "Annual income" and enter your yearly salary.
- Step 3: Drag the "Custom rent-of-income percentage" slider. The percentage shown next to the label updates as you move it, in one-point steps from 15% up to 50%.
- Step 4: Press Calculate. The headline result now reflects your chosen percentage rather than a fixed 30%.
- Optional: Open "Add monthly debts, expenses & a savings goal" underneath the slider to see a money-remaining breakdown that nets your custom recommended rent, debts, other expenses, and a savings-goal percentage out of your gross income.
As an example only: on $5,200/month gross income, leaving the slider at its 30% default gives a recommended rent of about $1,560/month. Dragging the slider to 26% instead — as a hypothetical, more conservative choice — brings that figure down to about $1,352/month, without needing to reach for a calculator app to do the multiplication separately.
Why a range, instead of just picking the "right" number
The slider deliberately spans wider than the four fixed presets — 15% at the conservative end, 50% at the stretched end — so it can accommodate very different situations without forcing anyone into an artificial middle ground. A renter prioritizing aggressive savings or paying down debt might explore values well under 25%. Someone in a high-cost market who has already decided rent is the budget line they're willing to stretch on might explore values above 40%. Neither end of the range is a recommendation by itself — it's simply the space the slider covers so your own number, whatever it turns out to be, has somewhere to land.
Worked example: same income, three slider positions
The table below is a hypothetical illustration of how the same $4,800/month gross income plays out at three different slider settings, compared with the standard 30% preset.
| Slider setting | Rent-of-income % | Recommended rent | Notes (example only) |
|---|---|---|---|
| Conservative end | 20% | $960 | Heavier debt load, example scenario |
| Standard default | 30% | $1,440 | Same as the fixed 30% preset |
| Stretched setting | 42% | $2,016 | High-cost-city stretch, example scenario |
Note the middle row: leaving the slider at its 30% default produces the exact same result as the calculator's original fixed guideline, so nothing changes for anyone who doesn't touch it. The slider only matters once you decide your own number is different from 30% — at which point it becomes the headline figure instead of a mental side-calculation.