DTI Ratio Improver Calculator

This calculator floors Monthly Debt to Eliminate at $0 (line 68): if your Current Monthly Debt Payments are already below the Target Monthly Debt Payment implied by your Target DTI %, it reports $0 to eliminate rather than a negative number representing spare room, so the figure only ever tells you how much you're over target, never how much headroom you have. Current Monthly Debt Payments dominates Monthly Debt to Eliminate: its ±10% span is 87.5% of Monthly Debt to Eliminate — well ahead of Monthly Gross Income and Target DTI % (each about 67.5%, tied because Target Monthly Debt Payment is a simple product of those two factors, line 65). Target DTI % never moves Current DTI Ratio at all — it's used only to compute the target you're comparing against, not the ratio you actually have today (lines 62-63). Monthly Gross Income edges out Current Monthly Debt Payments as the bigger driver of Current DTI Ratio under an equal-percentage probe (about 20.202% versus exactly 20.000% at the defaults), but not because the numerator "adds linearly" while income doesn't — the numerator, Current Monthly Debt Payments, is just as purely multiplicative in this ratio as income is; nothing in Current DTI Ratio = Current Monthly Debt Payments / Monthly Gross Income adds anything.

The edge is a subtler effect: 1/x is convex, so over a symmetric ±10% span, the increase from moving income down 10% (which pushes the ratio up more) slightly outweighs the decrease from moving it up 10%, producing a marginally larger two-sided span than the perfectly symmetric numerator does. This calculator does not model the difference between front-end DTI (housing costs only) and back-end DTI (all debt payments) that lenders actually distinguish between — Current Monthly Debt Payments here is defined as the total of all monthly debt obligations, so this calculator computes back-end DTI specifically, not front-end. It also does not account for non-debt qualifying factors like credit score, or how quickly the eliminated debt could realistically be paid down.