# Stackup

> Enter your apartment building's numbers and see how Fannie Mae, Freddie Mac and HUD loans size side by side, with the rule that caps each one.

Stackup is published by Janover Capital LLC. Contact: desk@janover.co.

MCP server for AI assistants: https://multifamily.online/mcp (Streamable HTTP, free, read-only, no key; compare_programs, get_program_terms, get_treasury_yields). Docs: https://multifamily.online/developers/

## Pages
- [Size your apartment loan under every agency program at once](https://multifamily.online/): Size an apartment loan under Fannie Mae, Freddie Mac and HUD limits side by side. See the max loan, the rule that caps it, and payments. Free, no signup.
- [About Stackup](https://multifamily.online/about/): Who runs Stackup, where its program numbers come from, how they are kept current, and what the app can and cannot tell you about a loan.
- [Contact Stackup](https://multifamily.online/contact/): Send Stackup a question or request. We read every message and reply by email.
- [Multifamily loan sizing for AI assistants: MCP server](https://multifamily.online/developers/): Free MCP server that sizes an apartment loan under Fannie Mae, Freddie Mac and HUD limits, with program terms and Treasury yields, for Claude and ChatGPT.
- [Disclosures](https://multifamily.online/disclosures/): What Stackup's loan estimates are and are not, who operates the site, how requests to the desk are handled, and our relationship to the agencies.
- [Put this calculator on your site](https://multifamily.online/embed/): Paste one iframe and your visitors can size an apartment loan under Fannie Mae, Freddie Mac and HUD limits on your page. A test version is live.
- [Guides from Stackup](https://multifamily.online/guides/): All guides from Stackup, newest first. Every multifamily loan program, sized against your building.
- [How Stackup sizes a multifamily loan: formulas and data](https://multifamily.online/method/): The formulas behind the comparison app: LTV and DSCR sizing, the rate, HUD mortgage insurance, program caps, and where each input comes from.
- [Privacy policy](https://multifamily.online/privacy/): What Stackup collects when you visit or contact us, why, who it is shared with, and how to reach us about it.
- [Multifamily loan program terms: Fannie, Freddie, HUD (2026)](https://multifamily.online/programs/): Max LTV, min DSCR, amortization, prepayment and recourse for Fannie Mae, Freddie Mac and HUD apartment loans, quoted from each source with its date.
- [Terms of use](https://multifamily.online/terms/): The terms that apply when you use Stackup, including what the information here is and is not.

## Guides
- [Fannie Mae vs Freddie Mac vs HUD 223(f): the same building, three loan sizes](https://multifamily.online/guides/fannie-freddie-hud-same-building/): One 45-unit building through Fannie Mae, Freddie Mac and HUD 223(f) at the same rate. HUD sizes about $720,000 larger here. Why, and what it costs.
- [Freddie Mac's Small Balance Loan program is gone. Here's what replaced it](https://multifamily.online/guides/freddie-mac-small-balance-loan-replaced/): Freddie Mac stopped taking SBL applications on April 30, 2026. Its replacement, Optigo Conventional Small, covers $2M to $10M loans on 5 to 50 units.
- [Can you use an SBA loan to buy an apartment building?](https://multifamily.online/guides/sba-loan-apartment-building/): SBA 7(a) and 504 loans can't finance apartment buildings. The SOP rule, the regulation behind it, the narrow exceptions, and what 5+ unit buyers use instead.