Child Tax Credit Calculator
This estimator helps you approximate federal child tax credit amounts based on common parameters: number of qualifying children, adjusted gross income (AGI), estimated tax liability, and earned income for potential refundable portions. It is intended for planning and educational purposes only.
Results are estimates generated from user inputs and conservative, commonly used phaseout and phase‑in rule representations. This tool does not file a tax return and does not replace professional tax advice or official IRS calculations.
Governance
Record f30186f11ea9 • Reviewed by Fidamen Standards Committee
Estimate total allowable child tax credit after income phaseouts and how much of that credit can be used against your tax liability.
Inputs
Advanced inputs
Defaults for Single filers
Defaults for Married filing jointly
Defaults for Married filing separately
Defaults for Head of household
Defaults for Qualifying widow(er)
Results
Estimated total credit after phaseout
$2,000.00
Estimated non‑refundable credit (applies to tax liability)
$1,000.00
Remaining credit that may be refundable
$1,000.00
| Output | Value | Unit |
|---|---|---|
| Estimated total credit after phaseout | $2,000.00 | USD |
| Estimated non‑refundable credit (applies to tax liability) | $1,000.00 | USD |
| Remaining credit that may be refundable | $1,000.00 | USD |
Visualization
Methodology
The calculator models three stages: compute a base credit by multiplying per‑child credit amounts by the number of qualifying children; apply an income phaseout to reduce the base credit; and split the post‑phaseout credit into the portion usable against tax liability (non‑refundable) and any remaining amount that could be refundable under a phase‑in rule.
Default per‑child credit amounts, phaseout thresholds, phaseout rate, and refundable phase‑in parameters are provided for common filing statuses. You may override defaults to reflect specific legislative changes or special situations.
Estimates use simple arithmetic expressions and common phaseout/phase‑in representations; they are intentionally straightforward for transparency and to enable quick scenario testing.
Key takeaways
This estimator provides transparent, editable defaults and shows intermediate steps so you can understand how inputs influence the credit.
It is designed for scenario planning and not as a substitute for professional tax preparation or official IRS calculations.
F.A.Q.
Is this an official IRS calculation?
No. This tool provides estimates for planning. For official guidance and rules that determine eligibility and exact amounts, consult the IRS or a tax professional.
Why do defaults include a phaseout threshold and rate?
Federal rules commonly reduce credits above income thresholds. The tool uses an explicit numeric threshold and a reduction rate so you can see how changes in income affect the credit. Users can adjust these defaults to reflect specific legislation or personal circumstances.
What does refundable mean here?
Refundable refers to any portion of the credit that can be issued as a refund even if you have little or no tax liability. This estimator includes a phase‑in style refundable calculation for illustrative purposes; actual refundable rules depend on law and filing details.
How accurate is the estimate?
Estimates are approximate. They simplify some legal details, exceptions, and interactions with other credits. Use results as a planning aid only and verify final amounts using official IRS forms or a tax preparer.
Sources & citations
- IRS — Child Tax Credit — https://www.irs.gov/credits-deductions/individuals/child-tax-credit
- IRS — Earned Income Tax Credit (for related refundable rules) — https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit-eitc
- NIST — Frameworks and best practices for software quality and testing — https://www.nist.gov
- ISO — Standards for information security and quality systems — https://www.iso.org
- IEEE — Software engineering best practices — https://www.ieee.org
- OSHA — Operational safety and risk guidance (organizational standards) — https://www.osha.gov
- IRS Publication 15-T — Federal Income Tax Withholding Methods — https://www.irs.gov/publications/p15t
- IRS Publication 505 — Tax Withholding and Estimated Tax — https://www.irs.gov/publications/p505
- IRS Tax Withholding Estimator — https://www.irs.gov/individuals/tax-withholding-estimator
Further resources
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
Record ID: f30186f11ea9What changed (latest)
v1.0.0 • 2025-11-19 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Public QA status
PASS — golden 25 + edge 120
Last run: 2026-01-23 • Run: golden-edge-2026-01-23
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
What changed (latest)
v1.0.0 • 2025-11-19 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Public QA status
PASS — golden 25 + edge 120
Last run: 2026-01-23 • Run: golden-edge-2026-01-23
Engine
v1.0.0
Data
Baseline (no external datasets)
Content
v1.0.0
UI
v1.0.0
Governance
Last updated: Nov 19, 2025
Reviewed by: Fidamen Standards Committee (Review board)
Credentials: Internal QA
Risk level: low
Reviewer profile (entity)
Fidamen Standards Committee
Review board
Internal QA
Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person
Semantic versioning
- MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
- MINOR: New features or fields that do not change existing outputs for the same inputs.
- PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.
Review protocol
- Verify formulas and unit definitions against primary standards or datasets.
- Run golden-case regression suite and edge-case suite.
- Record reviewer sign-off with credentials and scope.
- Document assumptions, limitations, and jurisdiction applicability.
Assumptions & limitations
- Uses exact unit definitions from the Fidamen conversion library.
- Internal calculations use double precision; display rounding follows the unit's configured decimal places.
- Not a substitute for calibrated instruments in regulated contexts.
- Jurisdiction-specific rules may require official guidance.
Change log
v1.0.0 • 2025-11-19 • MINOR
Initial publication and governance baseline.
Why: Published with reviewed formulas, unit definitions, and UX controls.
Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 5669d854cd42
- https://www.ieee.org
- https://www.irs.gov/credits-deductions/individuals/child-tax-credit
- https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit-eitc
- https://www.irs.gov/individuals/tax-withholding-estimator
- https://www.irs.gov/publications/p15t
- https://www.irs.gov/publications/p505
- https://www.iso.org
- https://www.nist.gov
- https://www.osha.gov