Child Tax Credit Phaseout MAGI Checker

Child-credit independently applicable steppedMAGIphaseout using each STARTED step, no smooth linear substitute, eligibility/refundability external. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.

Description

A stepped child-credit phaseout reduces credit for each started increment above an applicable MAGI threshold.

A stepped child-credit phaseout reduces credit for each started increment above an applicable MAGI threshold.^[1]

That staircase differs from a smooth linear phaseout.

When to use Child Tax Credit Phaseout MAGI Checker

Use this tool when you need to reproduce the stated calculation from measured records or independently selected model inputs. Establish jurisdiction, tax year, applicable authority, and eligible amounts or evidence before entering values. Minor-unit amounts use one currency; 12345 means 123.45 when that currency has 100 minor units per major unit. One basis point is 0.01 percentage points.

How to use Child Tax Credit Phaseout MAGI Checker and understand its results

Establish jurisdiction, tax year, applicable authority, and eligible amounts or evidence before entering values. Minor-unit amounts use one currency; 12345 means 123.45 when that currency has 100 minor units per major unit. One basis point is 0.01 percentage points.
Enter magiMinor, callerPhaseoutThresholdMinor, callerReductionPerStartedStepMinor, callerPhaseoutStepMinor, callerInitialCreditMinor, following the field table and rules below, then run the tool.
Read startedPhaseoutSteps, conditionalRemainingCreditMinor. Use the output meanings below to interpret units, signs, flags, and any nested result fields.
Correct reported input issues and run again. For a successful result, check the stated evidence coverage and assumptions before using it in your review.

Input field	Meaning	Value type	Requirement
magiMinor	MAGI minor	number	Required
callerPhaseoutThresholdMinor	Caller phaseout threshold minor	number	Required
callerReductionPerStartedStepMinor	Caller reduction per started step minor	number	Required
callerPhaseoutStepMinor	Caller phaseout step minor	number	Required
callerInitialCreditMinor	Caller initial credit minor	number	Required

Use nonnegative safe-integer MAGI, threshold, reduction per step, positive step size, and initial credit in matching minor units. Floor income excess at zero, divide with integer ceiling, multiply by reduction, and floor remaining credit at zero. Eligibility and refundability are external.

steps=ceil(max(0,MAGI−threshold)/step); remaining=max(0,credit−steps×reduction)

Symbols follow the input and output meanings and the calculation rules above.

Output field	Meaning	Value type
startedPhaseoutSteps	Started phaseout steps	number
conditionalRemainingCreditMinor	Conditional remaining credit minor	number

json

{
  "input": {
    "magiMinor": 125,
    "callerPhaseoutThresholdMinor": 100,
    "callerReductionPerStartedStepMinor": 5,
    "callerPhaseoutStepMinor": 10,
    "callerInitialCreditMinor": 30
  },
  "output": {
    "startedPhaseoutSteps": 3,
    "conditionalRemainingCreditMinor": 15
  }
}

Limitations and assumptions

Eligibility, rates, dates, definitions, and exceptions are independently supplied facts. The arithmetic is not a complete return calculation or a determination of tax liability.

Missing required fields, unknown fields, wrong types, and violated calculation rules are input issues. Numeric values must be finite; nonfinite results are rejected.

Alternative or Complementary methods

For a related review, use Filing Status Dependents Tree Picker: Filing-status review combines marital, dependent, and household facts. This checker applies your positive evidence requirements and keeps multiple possible classes when the evidence is incomplete. For a complementary step, use Roth MAGI Phaseout Eligibility Checker: A linear Roth contribution phaseout model combines MAGI with supplied full and zero-contribution boundaries. It gives a conditional arithmetic amount while leaving statutory rounding and eligibility rules to the applicable reference.

References

Child Tax Credit Phaseout MAGI Checker — tool.io

Similar or alternative tools

Filing Status Dependents Tree Picker
Filing-status review combines marital, dependent, and household facts. This checker applies your positive evidence requirements and keeps multiple possible classes when the evidence is incomplete.
Roth MAGI Phaseout Eligibility Checker
A linear Roth contribution phaseout model combines MAGI with supplied full and zero-contribution boundaries. It gives a conditional arithmetic amount while leaving statutory rounding and eligibility rules to the applicable reference.