References & Official Sources

All calculator formulas and blog content are based on official U.S. government publications, regulations, and public data. This page catalogs every primary source used by StudLoanCalc.

U.S. Department of Education — Federal Student Aid

National Student Loan Data System (NSLDS) — Official federal loan database; view your total federal loan balances and servicer
Federal Student Aid (studentaid.gov) — Primary portal for federal student aid information
Loan Simulator — Official ED loan simulator tool
PSLF Help Tool — Official PSLF employment certification and payment tracking
Repayment Plans Overview — All federal repayment plan descriptions
Interest Rates and Fees — Current federal student loan interest rates
Loan Forgiveness & Cancellation — Official forgiveness program descriptions

Federal Regulations (Code of Federal Regulations)

34 CFR Part 682 — Federal Family Education Loan (FFEL) Program
34 CFR Part 685 — William D. Ford Federal Direct Loan Program
34 CFR §685.209 — Income-Driven Repayment (PAYE)
34 CFR §685.217 — Teacher Loan Forgiveness Program
34 CFR §685.219 — Public Service Loan Forgiveness Program

Federal Register — Rulemaking

Federal Register — Official daily publication for rules, proposed rules, and notices of federal agencies
RAP (Replacing SAVE) Final Rule — Published in Federal Register, 2026
IDR Account Adjustment — One-time payment count adjustment announcement

Federal Loan Servicers

MOHELA — PSLF-designated loan servicer
Nelnet — Federal student loan servicer
Aidvantage — Federal student loan servicer
Edfinancial Services — Federal student loan servicer
Default Resolution Group — For defaulted federal student loans

U.S. Department of Health & Human Services — Poverty Guidelines

HHS Poverty Guidelines (2026) — Used for IDR discretionary income calculations

Internal Revenue Service — Tax References

IRS Publication 970 — Tax Benefits for Education (including student loan interest deduction)
Form 1098-E — Student Loan Interest Statement
Internal Revenue Code §221 — Interest on education loans
Internal Revenue Code §108(f) — Student loan forgiveness exclusion from gross income

Consumer Financial Protection

CFPB — Student Loans — Consumer guidance on student loans
CFPB — Student Loan Debt Collective — Borrower complaint and information portal

Loan Repayment & Forgiveness for Specific Professions

Teacher Loan Forgiveness — Official ED program page
Nurse Corps Loan Repayment Program — HRSA Nurse Corps
NHSC Loan Repayment Program — National Health Service Corps

Data & Research

Federal Student Loan Portfolio — ED Data Center, aggregate loan statistics
FRED Economic Data — Federal Reserve Economic Data (income growth benchmarks)

Note: External links open in new tabs. StudLoanCalc is not affiliated with any government agency or loan servicer. References are provided for transparency and verification purposes.

How Each Calculator Uses These Sources

Every tool on the site is backed by a specific subset of the sources above. The mapping below shows which references drive which calculator, so you can trace any result back to its controlling authority.

Calculator	Primary sources it relies on	What the source controls
Amortization	Higher Education Act rate tables; 34 CFR §685	Interest accrual, standard PMT formula, capitalization rules
5-Plan Compare	34 CFR §685.209 (PAYE), §685.208 (IBR), RAP Final Rule, HHS poverty guidelines	Discretionary-income percentages, poverty multipliers, plan eligibility
PSLF	34 CFR §685.219; studentaid.gov/pslf; MOHELA servicing guidance	120-qualifying-payment count, forgiveness mechanics, employer rules
Refinance	Federal Student Aid rate tables; CFPB student-loan guidance; IRC §108(f)	Rate comparison, lost-protection disclosure, tax treatment of forgiveness
Debt Payoff	Standard amortization math; CFPB payoff guidance	Avalanche vs snowball ordering, interest minimization
State Guides	Each state's official 529 plan site and state higher-ed agency	Plan names, agency contacts, state-level tax and relief notes

Understanding the Regulatory Hierarchy

When sources appear to conflict, we follow the legal hierarchy rather than the most recent headline. Knowing the order helps you weigh any claim you read online:

Statute (law passed by Congress): The Higher Education Act and the Internal Revenue Code are the top layer. Everything below must conform to them.
Regulations (Code of Federal Regulations): Agencies translate statutes into operative rules. We cite 34 CFR (Education) and 26 CFR (Tax) as the binding text.
Federal Register: Proposed and final rules, including the 2026 RAP rulemaking, are published here before taking effect. This is where to confirm a change is final, not just proposed.
Agency guidance & tools: studentaid.gov pages, servicer notices, and the Loan Simulator put the rules into practice. They are authoritative for procedure but cannot override the statute or CFR.
News & commentary: Useful for context, but always trace a specific claim back to one of the four layers above before relying on it.

Glossary with Source Attribution

Key terms, each tied to the source that defines it, so you can verify the definition directly.

Adjusted Gross Income (AGI): Defined by the Internal Revenue Code (26 U.S.C. §62); the income base used for IDR payment formulas. IRS Form 1040.
Discretionary income: For IDR plans, AGI minus a multiple of the HHS poverty guideline (150% for IBR/PAYE). Defined in 34 CFR §685.208–.209 and the RAP rule. HHS Poverty Guidelines.
Poverty guideline: Annual figure published by HHS used in IDR math; differs by household size and by Alaska/Hawaii. HHS ASPE.
Public Service Loan Forgiveness (PSLF): Forgiveness after 120 qualifying payments while working eligible public-service employment. 34 CFR §685.219. studentaid.gov/pslf.
RAP (Repayment Assistance Plan): The income-driven plan introduced in 2026 to replace SAVE. Final rule published in the Federal Register. Federal Register.
Student Loan Interest Deduction: An above-the-line deduction up to the statutory cap under IRC §221, reported on Form 1098-E. IRS Publication 970.
Tax bomb: The potential ordinary-income tax on forgiven balances (e.g., under some IDR discharges), generally excluded for PSLF and certain discharges by IRC §108(f). 26 U.S.C. §108(f).
Capitalization: The addition of unpaid interest to the principal balance, which then accrues interest itself. Governed by 34 CFR §685.202. 34 CFR §685.202.
Deferment & Forbearance: Periods that pause or reduce payments; interest may or may not accrue depending on loan type and program. Rules at 34 CFR §685.204–.205. 34 CFR Part 685.
IDR Account Adjustment: A one-time review that credited certain past periods toward IDR and PSLF forgiveness. Announced via ED and the Federal Register; verify your count with your servicer. ED IDR Account Adjustment.

How to Read a Federal Citation

Government sources are cited in a shorthand that looks intimidating but is easy once decoded. Being able to read it lets you open the exact provision yourself rather than trusting a summary.

"34 CFR §685.209" means Title 34 (Education) of the Code of Federal Regulations, Part 685 (Direct Loan Program), section 209. Open it at ecfr.gov by navigating to Title 34 → Part 685.
"26 U.S.C. §221" means Title 26 (Internal Revenue Code), section 221. The U.S. Code is the codified statute; Cornell's Legal Information Institute hosts a free, searchable version.
"RAP Final Rule, Federal Register 2026" means the rule as published in the Federal Register, the official daily journal. The Federal Register shows the rule's effective date, which determines when it actually applies.
"HHS Poverty Guidelines (2026)" means the annual guidelines issued by the HHS Assistant Secretary for Planning and Evaluation, used in IDR math.

When a blog post, calculator, or advisor states a specific rule, ask for the citation. If they cannot give one (or give only a news article), treat the claim as unverified until you check the primary source.

Cross-Checking a Claim You Read Elsewhere

The same discipline we apply to our own content applies to anything you read about student loans. A quick three-step check separates reliable guidance from speculation:

Find the primary source. Search the claim plus "site:studentaid.gov" or "site:ecfr.gov" to see if a statute or regulation supports it.
Check the date. Student-loan rules changed substantially in 2025–2026. A pre-2025 article about SAVE may describe a plan that no longer exists; confirm the current plan (RAP) instead.
Confirm with your servicer. Even a correct general rule can apply differently to your specific loan type (Direct, FFEL, Perkins) or status. Your servicer's written statement is what governs your account.

State-Specific Sources

Federal rules are national, but state treatment of 529 plans, state tax deductions, and state loan-repayment programs varies widely. Each page in our State Guides section links directly to that state's official 529 plan website and its state higher-education or student-aid agency. We deliberately link to the .gov or official plan domain rather than summarizing state tax law ourselves, because state provisions change frequently and are easy to state incorrectly. If you are weighing a state tax benefit, confirm the current limits with the linked agency and a local tax professional.

Citation Standard & Update Cadence

Primary over secondary: We prefer statutes, the CFR, and agency publications over news articles.
Stable links: Links point to canonical agency URLs (studentaid.gov, ed.gov, irs.gov, ecfr.gov, aspe.hhs.gov, consumerfinance.gov) that are unlikely to change.
Periodic re-verification: Reference links are reviewed on the same cadence as policy parameters; the page "Last Reviewed" date reflects the most recent check.
Dead-link reporting: If you click a reference and it no longer resolves, please report it via the contact route on our Terms of Use page and we will repair or replace it.
No affiliate or sponsored sources: No reference link earns us a commission; inclusion reflects usefulness and authority, not commercial arrangement.

Are these government links official?

Yes. Every external link points to an official .gov, .mil, or authoritative source such as the eCFR or a state's official 529 plan domain. We avoid linking to unofficial summaries where a primary source exists.

What if a reference link is broken or outdated?

Report it through the contact route on our Terms of Use page. We periodically re-verify links and will repair or replace any that no longer resolve, then update the page review date.

Why do you cite regulations (CFR) instead of just news articles?

Primary sources are authoritative and stable. A news article may misinterpret or lag a rule; the controlling 34 CFR or 26 CFR text is what servicers and courts actually apply, so we cite it directly.

How do the state guides source their data?

Each state guide links to that state's official 529 plan website and its state higher-education or student-aid agency. State tax and relief notes are written conservatively with a "confirm current limits" caveat rather than stating figures that may be wrong.

Do you cite the interest-rate figures used in calculators?

Yes. Rate assumptions come from the Federal Student Aid published annual rates under the Higher Education Act, and they are refreshed each academic year when ED releases them.

Can I cite StudLoanCalc in my own work?

You may link to our pages, but for any factual claim please cite the primary government source listed here. Citing the original statute, regulation, or agency page is more authoritative than citing a calculator built on top of it.