Affordability Index

A single number that tells you whether a purchase fits your finances

The Formula

The Fundamental Idea

AI =

Safe Savings + (Monthly Surplus × T) Purchase Price

Where Safe Savings = max(0, S − 6E) and Monthly Surplus = I − E − D − M

The Detailed Formula

AI =

max(0, S − 6E) + (I − E − D − M)T P

P Purchase price

S Liquid savings

E Essential monthly expenses

I Monthly take-home income

D Existing monthly debt payments

M Monthly savings / investment target

T Purchase horizon, in months

Filled in from your saved details. Changes here stay in this calculation — edit My details to change them for good.

What are you buying? This field is required

Purchase price (P) This field is required

Liquid savings (S) This field is required

Essential monthly expenses (E) This field is required

Monthly take-home income (I) This field is required

Existing monthly debt payments (D) This field is required

Monthly savings / investment target (M) This field is required

Purchase horizon, months (T) This field is required

AI Range	Meaning
< 0	Cannot afford
0 – 1	Not comfortably affordable
1 – 2	Barely / moderately affordable
2 – 3	Affordable — the practical threshold
3 – 5	Comfortable
5+	Very comfortable

The crucial cutoff is AI ≥ 2 — that's the working definition of "financially affordable" used throughout this tool.

Affordability Index —

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Need or want?

The honest question

Why your parents bought one

When it becomes a need

Written by an AI model to help you think it through — not a verdict on your situation, and not financial advice.

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