How this instrument works
A hard-cutoff design like this one asks a single yes-or-no question: is adjusted gross income at or below the cap? Clear the bar and the full flat payment lands untouched; miss it by even a cent and the payment is zero. That binary test is the opposite of how the three actual federal stimulus rounds worked — the CARES Act's $1,200 check, the December 2020 $600 payment, and the American Rescue Plan's $1,400 rebate all shaved a slice off the payment for every dollar of income past a threshold, so the amount stepped down gradually instead of falling off a ledge.
Nobody has run this exact $40,000-cap, $1,200-flat combination through Congress — the figures here are a demonstration model, sized to isolate the cliff mechanic so it can be compared directly against a taper. But the mechanic itself shows up outside stimulus law: Medicaid income tests, SNAP's gross-income screen, and the pre-2021 rule that cut off Affordable Care Act premium tax credits entirely above 400% of the poverty line all work the same way — one side of the line gets the full benefit, the other side gets nothing, with no ramp between.
The mistake this instrument exposes is assuming 'just over the cap' means 'a little less benefit,' the way a phase-out behaves. It doesn't: earning one dollar past incomeCap does not trim the payment by a nickel, it erases the entire flatPayment. A worker whose AGI drifts from $39,600 to $40,300 after a bonus or a few extra shifts can end up with less total income than if the raise had never happened — a real effect economists call a benefit cliff, and the reason most enacted relief programs chose a taper over a hard line like this one.
- Set Flat payment amount, $ to the dollar figure everyone under the cap receives — $1,200 by default.
- Enter Adjusted gross income, $ for the household or filer being tested.
- Set Income cap, $ (hard cutoff, no phase-out) to the ceiling AGI must not exceed.
- Read Payment amount, $ — it snaps to the full flat payment at or below the cap and to $0 the instant AGI passes it.
- Nudge Adjusted gross income, $ across the cap by a single dollar to watch the payment fall off the ledge instead of tapering.
Worked example — $35,000 AGI against a $40,000 cap
Set Flat payment amount, $ to $1,200, Adjusted gross income, $ to $35,000, and Income cap, $ (hard cutoff, no phase-out) to $40,000 — the sheet's own defaults. Because $35,000 sits below the $40,000 ceiling, the comparison passes cleanly and Payment amount, $ returns the full $1,200.00, with nothing shaved off for sitting close to the line.
Raise Adjusted gross income, $ to $45,000 with the same $40,000 cap and the payment does not shrink toward zero — it snaps straight to $0.00, because $45,000 is over the cap regardless of margin. Move AGI to exactly $40,000 instead and the full $1,200.00 still pays, since the cutoff includes the cap itself; only AGI strictly above it forfeits the payment.
Questions
Why does earning one extra dollar wipe out the entire payment?
Because this design uses a hard cutoff instead of a phase-out: the formula only checks whether AGI is at or below incomeCap and gives no partial credit for landing close. Real stimulus rounds instead cut the payment gradually — a few cents per excess dollar — so a dollar over the line cost pennies, not the whole $1,200. A hard cap trades that smoothness for one comparison and one of two outcomes.
Is $40,000 the actual income limit any stimulus check used?
No — no enacted federal stimulus round used a flat $40,000 hard cutoff; all three used gradual phase-outs starting at $75,000 for a single filer or $150,000 for a joint return, with different tapering rates. This sheet's $40,000 ceiling and $1,200 flat payment are demonstration figures chosen to make the cliff mechanic easy to see and test, not a historical threshold to look up on a real return.
What happens exactly at AGI equal to the cap?
It still qualifies for the full flat payment — the comparison is inclusive, so AGI equal to incomeCap pays exactly what AGI one dollar below it pays. The cliff falls the instant AGI exceeds the cap, not at the cap itself: with this sheet's defaults, $40,000.00 pays $1,200.00 while $40,000.01 pays $0.
Why would any program choose a cliff over a phase-out?
Mainly for administrative simplicity — a hard cutoff needs one comparison and one lookup table, while a phase-out needs a formula, a start point, and an end point, and produces a check amount that differs for nearly every household. Programs built quickly, or distributed through systems that cannot easily run a sliding scale, sometimes accept the cliff's unfairness at the margin in exchange for speed and a payment anyone can verify by eye.
Can more than one benefit cliff hit at the same time?
Yes, and that is when the effect compounds hardest: if a raise pushes AGI over this cap and also over a separate program's Medicaid or subsidized-childcare limit in the same year, a household can lose several benefits at once for a single dollar of extra income. Modeling one cliff in isolation, as this sheet does, is a first step toward spotting that stacking risk — it does not add up several programs' combined effect.
Why test adjusted gross income instead of gross pay or take-home pay?
Adjusted gross income is the line item real means-tested and tax-linked programs actually test, because it already nets out specific above-the-line items like retirement contributions before any benefit rule is applied. Gross pay overstates what counts toward a cap, and take-home pay understates it by removing withholding unrelated to eligibility, so AGI is the consistent figure this sheet and real programs both rely on.
References
- IRS — Coronavirus tax relief and Economic Impact Payments
- Federal Reserve — Report on the Economic Well-Being of U.S. Households
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.