Getting started
The Adjuststack calculator breaks down exactly which loan-level price adjustments (LLPAs) apply to a conventional loan scenario and why. There is no account, no sign-up, and no data stored — every calculation is ephemeral.
- Go to the Calculator page.
- Select your loan characteristics from the seven dropdowns: FICO band, LTV/CLTV range, loan purpose, occupancy, property type, loan amount band, and lock period.
- Click Calculate adjustments.
- Read the stacked ledger: every adjustment is listed as its own row, with the grid cell reference and effective date. The rows sum to a final price.
The calculator validates every input. If a selection is missing or a combination falls outside the published grid, the error message explains what is needed.
Frequently asked questions
1. How is the final price calculated? Is this a mortgage rate?
The calculator starts with a base price (100.500) and applies the published Fannie Mae LLPA adjustments as additive or subtractive values — it is not a loan rate, APR, or monthly payment. The output shows how the base price changes due to each adjustment factor. Every adjustment row cites the exact grid cell (e.g. "FICO 680–699 at 80.01–85% LTV — Fannie Mae LLPA Matrix, effective 2025-04-01"). See the home page for a worked example.
2. Why does my lender's quote not match what this calculator shows?
There are several reasons a lender's quote can differ. Lenders set their own base pricing, which is not visible to this calculator. This tool models only the seven published LLPA adjustment categories from the Fannie Mae matrix: FICO/LTV, purpose, occupancy, property type, loan amount, and lock period. It does not model ARM adjustments, DTI-based adjustments, score-tier changes, lender overlays, or private mortgage insurance. Additionally, lenders may apply adjustments in a different stacking order, or use a different grid revision. Always verify the arithmetic against your lender's loan estimate and the current published matrix.
3. Which grids are loaded and how up-to-date are they?
The calculator currently loads the Fannie Mae LLPA Matrix, effective 2025-04-01. The effective date is displayed on every calculator page and on every output ledger. The grid is baked into the code as a data file. When Fannie Mae publishes a new revision, the grid data will need to be updated by the operator. Freddie Mac grids are not loaded yet (see Known limitations).
4. Can I save or export my calculation?
No. Adjuststack does not save scenarios, user accounts, or calculation history. Every calculation is ephemeral — it exists only in your browser until you refresh or navigate away. If you need a record of the result, take a screenshot or note down the figures. CSV export, saved scenarios, and batch comparison are listed as planned features on the Pricing page but are not yet available.
5. Is this a rate quote, loan lock, or pre-approval?
No. The output of this calculator is an arithmetic display based on published GSE grids. It is not a mortgage rate quote, a rate lock, a pre-approval, a commitment, or an offer of credit. No lender, broker, or financial institution is affiliated with this service. Do not present the output as a rate quote to a borrower or lender — see the Terms of Service for acceptable use.
6. What happens if my FICO or LTV falls outside the grid?
The calculator will return a clear error message: "outside the published grid". It will never extrapolate, clamp to the nearest cell, or silently print a number it cannot verify. For example, a FICO below 620 or an LTV above 97% will be rejected — those ranges have no cell in the current Fannie Mae LLPA matrix.
Known limitations
The Adjuststack calculator is an honest, transparent display of published LLPA data. However, several capabilities that a production-grade mortgage pricing tool would have are not yet built. These are listed without apology — each is a deliberate current limitation:
Only Fannie Mae, no Freddie Mac. The calculator uses the Fannie Mae LLPA Matrix (2025-04-01) only. Freddie Mac's equivalent grids are not modelled. Users seeking Freddie Mac comparisons cannot use this tool for that purpose.
One grid revision; not auto-refreshing. The grid data is baked into the code, not fetched from a live API. When Fannie Mae publishes a new matrix revision, the calculator will display stale data until the operator updates the code. Always check the effective date shown on the page.
Seven adjustment categories only. The calculator models FICO/LTV, loan purpose, occupancy, property type, loan amount band, and lock period. It does not model ARM adjustments, DTI-based LLPAs, credit score tier changes, lender overlays, private mortgage insurance (PMI), or any state-specific adjustments.
No accounts, no saved scenarios, no history. Every calculation is ephemeral. There is no way to save, compare, export, or revisit a previous calculation. Session history is confined to your browser tab; closing it erases the result.
No email or notifications. This service has no email sender. It cannot send alerts when grid revisions are published, notify users of calculation results, or deliver reports. No email address is collected or stored.
No payment processing. The Pro plan on the Pricing page is listed as "coming soon." No payment mechanism is connected. The Free plan is the only available product.
Not a live rate sheet. The calculator does not pull live rates or pricing from any lender. The "base price" is a fixed starting point for demonstrating adjustment arithmetic — not a market rate.
No contact channel yet. Support is not currently reachable by email, phone, or postal mail. The operator has not yet established a communication channel. If you encounter a bug, a discrepancy in the grid data, or a feature request, please document it. Once a contact method is established, this page will be updated. In the meantime, the Terms of Service and Privacy Policy describe the service's current operating practices.
Report an issue
If you have found an error in the calculator — a wrong adjustment value, a missing grid cell, a calculation that does not match the published matrix — please record the details including the inputs you used, the output you received, and the grid reference you are comparing against. The operator relies on user reports to catch data-entry errors and grid-revision gaps.
There is no email or form available yet to submit these reports. The needs.md file maintained by the operator tracks outstanding requirements, and establishing a support contact channel is one of them.