How this instrument works
The second stimulus check — formally the second Economic Impact Payment, or EIP2 — was authorized by the Consolidated Appropriations Act, 2021, a roughly $900 billion COVID-relief bill signed December 27, 2020. It paid $600 for every eligible adult on the return and another $600 for every qualifying dependent under age 17, a narrower dependent rule than the third round used three months later.
The phase-out formula mirrors the taper the first stimulus check used, but scaled down: the formula strips five percent of whatever AGI sits past the threshold straight out of the base payment, and the result never falls below zero. A $1,200 base can absorb $24,000 of excess income before it's gone; a $600 base only stretches across $12,000, because halving the payment also halves how much excess the same percentage rate can burn through. That's why a single filer with no dependents was fully phased out by $87,000 in round two but not until $99,000 in round one — a gap that trips up anyone comparing the two rounds from memory instead of the arithmetic.
The second round moved unusually fast because the enabling law itself set a deadline: the IRS had to stop issuing EIP2 payments by January 15, 2021, just nineteen days after the December 27 signing — a hard statutory cutoff neither the first nor third round carried. A 2019 return still processing, or a bank account closed since the last filing, could miss that narrow window entirely, leaving no deposit or paper check to point back to. The only route back to that money was listing it as the Recovery Rebate Credit on the 2020 tax return filed months later, which is why a working EIP2 figure today is usually standing in for an entitlement nobody received, rather than confirming a number against a payment that already landed.
- Enter Eligible adults with the number of adults on the return — 1 for a single filer, 2 if filing jointly.
- Set Qualifying dependents (under 17) to how many dependents were under age 17 at the end of 2020; older dependents don't count here.
- Enter Adjusted gross income, $ from the return being checked, not gross wages or take-home pay.
- Set Phase-out threshold, $ (filing-status dependent) to $75,000 single, $112,500 head of household, or $150,000 joint.
- Compare Base payment before phase-out, $ against Estimated payment, $ to see exactly how much the 5% taper removed.
Worked example — a joint filer at the $150,000 threshold
Take the golden case: two eligible adults, two qualifying children under 17, and a household AGI landing exactly on the joint-filer threshold. Enter adults = 2, dependents = 2, agi = 150000, and phaseoutThreshold = 150000, the starting point for joint filers under the December 2020 relief bill. Base payment before phase-out, $ works out to $600 × (2 + 2), or $2,400.
Because AGI sits exactly at the $150,000 threshold, the excess is $0 and 5% of nothing is nothing, so Estimated payment, $ returns the full $2,400 unreduced — the golden case where the taper hasn't started biting yet. Raise the same household's AGI to $170,000 instead, $20,000 over threshold, and the 5% taper removes $1,000, cutting the payment to $1,400 — a fast decline once the threshold is crossed, because $600 spreads over a narrower income band than the $1,200 first check did at the identical 5% rate.
Questions
How is the second stimulus check different from the first and third rounds?
It paid $600 per eligible adult and per qualifying dependent under 17, versus $1,200 in the first round and $1,400 for every dependent regardless of age in the third round. The income thresholds ($75,000 single, $150,000 joint) matched the first check exactly, but the payment phased out twice as fast per dollar of income because the smaller base burns off at the same 5% rate.
Why does a $600 payment disappear faster than the $1,200 first check?
Both checks reduce the base payment by 5% of AGI above the threshold, but a $1,200 base absorbs $24,000 of excess income before hitting zero while a $600 base absorbs only $12,000. A single filer with no dependents phased out completely at $99,000 AGI under the first check but at just $87,000 under the second — the same rate applied to half the money.
Why doesn't a college student or elderly dependent count here?
The December 2020 law used the Child Tax Credit's under-17 age test, the same rule the first stimulus check used — a dependent who turned 17 before the end of 2020 added nothing to the payment. That changed only with the third round in March 2021, which paid the full $1,400 for a dependent of any age, college students and elderly parents included.
I never received this payment — what do I do with this number?
This instrument reproduces the entitlement formula only; it does not file anything. If the figure here is higher than what arrived, the shortfall was typically claimed as the Recovery Rebate Credit on line 30 of the 2020 Form 1040, using whichever adjusted gross income and dependent count applied to that specific return.
Does the 5% phase-out rate ever change between rounds?
No. Both the first and second rounds cut the base payment by the same five percent of whatever AGI exceeded its threshold, a rate written directly into each bill. What changed between those two rounds was only the base amount and the dependent age cutoff — the third round abandoned the percentage taper entirely for a straight-line band that phases out over a fixed dollar range instead.
Is the head-of-household threshold the same as for single filers?
No. The December 2020 law set a $75,000 start for single filers, $112,500 for head of household, and $150,000 for joint filers — the same three-tier structure the first stimulus check used. Enter the figure matching the filing status being checked into Phase-out threshold, $ (filing-status dependent).
References
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.