How to Underwrite a Multifamily Deal in Excel in 15 Minutes

Most multifamily deals do not take 15 minutes to underwrite.

That is the trap.

The underwriting rarely takes 15 minutes.

The cleanup does.

The rent roll cleanup.

The T12 cleanup.

The missing assumptions.

The category mapping.

The copy-paste gymnastics nobody talks about.

By the time most investors actually start underwriting a deal, they have already spent 45 minutes fighting the files.

The spreadsheet was not the bottleneck.

The workflow was.

The spreadsheet is rarely the bottleneck. The workflow is.

Once the inputs are clean, the actual underwriting process is fast.

Very fast.

First, what “15 minutes” actually means

This is not full due diligence.

It is not a final investment committee memo.

It is not the version where you have already reviewed every lease, walked units, verified contracts, and debated every assumption with the team.

This is a structured first-pass underwrite once the core files are available.

You need:

rent roll
T12
basic debt assumptions
purchase price or pricing guidance
initial business plan assumptions

If those inputs are available and clean, the first-pass decision can happen fast.

If they are messy, the clock does not start yet.

That distinction matters.

The 15 minutes is what underwriting actually looks like once the workflow stops fighting you.

The real reason underwriting takes so long

It is not complexity.

It is friction.

Messy rent rolls. Inconsistent T12 formats. Broken category mappings. Missing data. Manual cleanup.

That is where time disappears.

Not in the model.

And once that friction is removed, underwriting becomes a decision exercise.

Not a data-entry exercise.

That single shift is what separates someone screening 30 deals a quarter from someone screening five.

Broken workflow vs clean workflow

Broken workflow	Clean workflow
Manually clean rent roll	Parse rent roll into usable structure
Rebuild T12 categories by hand	Map T12 into underwriting categories
Hunt for missing assumptions	Use a standard input checklist
Copy and paste across tabs	Push clean data into the model
Spend time formatting	Spend time deciding
Underwrite inconsistently	Underwrite the same way every time

Most investors do not lose time because they lack intelligence.

They lose time because every deal starts from scratch.

The 15-minute underwriting framework

Here is the actual workflow, broken down by what gets checked at each stage.

Time	Stage	What you check
0–3 min	Inputs	Unit count, occupancy, rent roll structure, T12 format
3–7 min	Revenue	GPR, loss to lease, concessions, bad debt, other income
7–10 min	Expenses	Payroll, R&M, utilities, taxes, insurance, management
10–13 min	Debt + plan	Rate, leverage, DSCR, renovation premium, timing
13–15 min	Decision	NOI, DSCR, return profile, stress case, obvious red flags

This is not meant to replace deeper underwriting.

It is meant to tell you whether the deal deserves deeper underwriting.

That is the point.

Minute 0–3: Clean the inputs

This is where most people get stuck.

It is also where most of the day disappears in a broken workflow.

The inputs you need ready: structured rent roll, structured T12, consistent expense categories, clean unit count, clear occupancy picture, and your basic deal assumptions on hand.

Purchase price. Target leverage. Expected hold period. Initial business plan.

Nothing fancy.

Just enough to stop guessing.

In a clean workflow, this stage is mechanical.

You are not analyzing yet.

You are confirming the file set is usable.

Unit count ties between the rent roll and the OM. The T12 has 12 months, not 11 with one month missing. Occupancy on the rent roll is at least in the same neighborhood as what the broker quoted.

If anything fails here, stop.

Either get the right files or move on.

There is no point underwriting from a broken file set.

Minute 3–7: Normalize revenue

This is usually where the deal starts changing.

The broker's revenue story is rarely the same as the property's revenue story.

Sometimes the gap is small.

Sometimes it is the entire deal.

Now you pressure-test income.

Not what is reported.

What is real.

Run through these adjustments in order:

Loss to lease: compare in-place rent average against the rent roll's market rent column. If loss-to-lease is over 5%, validate market rent against actual signed leases in the submarket before treating any of it as upside.
Concessions: scan the most recent three to four months of leases on the rent roll for clustering. If concessions are concentrated in recent leases, the T12 may understate the true concession run-rate.
Bad debt: look at the trailing-three-month bad debt trend, not just the T12 average. The trailing three months often tell you more about where the property is going.
Other income: cut anything that looks lumpy or non-recurring. Keep recurring streams like laundry, parking, RUBS, and late fees.
Future residents and down units: these are not current revenue. Strip them out before calculating economic occupancy.

Reported revenue is often cleaner than real revenue.

And cleaner is not always more accurate.

Minute 7–10: Normalize expenses

This is where discipline matters.

The fastest path through is to ask one question per line item:

Is this expense forward-realistic, or is it just historical?

Focus on these in order of impact:

Real estate taxes: if the seller's basis is materially below your purchase price, plan for reassessment. In most markets, the basic starting point is the new assessed value times the current millage rate.
Insurance: trailing premium is almost never the right number anymore. Underwrite to a fresh quote, or apply a realistic uplift in hardening markets if you do not have one yet.
Payroll: confirm staffing matches the unit count and asset class. A 200-unit Class B asset with unusually low payroll is not automatically efficient. It may just be understaffed.
R&M and turnover: low historical R&M is rarely free upside. Often, it is deferred work.
Management fees: if the T12 shows below-market management expense, the property may be self-managed or underreported. Either way, your ownership will still have a cost.

Taxes and insurance alone can reshape the deal.

They deserve more than 60 seconds.

Minute 10–13: Build debt and business plan

Now layer in reality.

Debt has a way of making vague optimism more obvious.

On the debt side, you are checking interest rate, amortization, leverage, DSCR constraints, refinance assumptions, interest-only period, and debt yield pressure.

The fastest sanity check:

At your current NOI assumption, does DSCR clear the lender's minimum?

Does debt yield still make sense?

If not, you are either over-leveraged, too aggressive on NOI, or both.

Then test the business plan.

Rent growth assumptions need to be defensible against the comp set, not against the last cycle.

Renovation premiums need actual achieved-rent comps, not the seller's pro forma.

Renovation timing matters too.

A 24-month value-add plan that requires 40 turns a quarter on a property currently turning 12 units a quarter is not just a rent assumption.

It is a timeline problem.

If the plan only works in perfect conditions, that is your answer.

Minute 13–15: Stress test and decide

This is the part most people rush.

Do not.

Push the assumptions on five dimensions:

exit cap expansion from your base case
rent growth at half your base assumption
insurance higher than underwritten
full tax reassessment instead of phased reassessment
renovation premium lower than projected

Then ask:

Does this deal still hold up?

If it does not, it probably never did.

At least not at that price.

A quick example: 15 minutes through a 160-unit deal

Here is what this actually looks like in practice.

A 160-unit Class B garden property comes in.

The broker is asking $32 million.

T12 NOI is $1.92 million.

Headline cap rate is right at 6%.

The property is 94% occupied.

Light value-add story.

Modest rent upside.

On the surface, the deal looks fine.

Here is how the 15 minutes play out.

Minutes 0–3: Inputs

The rent roll and T12 come in clean.

Unit count ties at 160.

Occupancy on the rent roll matches the broker's 94% claim.

T12 categories are mappable.

Clock starts.

Minutes 3–7: Revenue

Four minutes in, the rent roll starts telling a different story.

Concessions are running about $4,800 per month and they are clustered in the most recent leases.

That is not random.

That is a leasing trend.

Annualized, it removes roughly $58,000 of revenue the broker's story was not really accounting for.

Bad debt trailing three months is running at 3.1%, versus the T12 average of 1.9%.

Loss to lease looks like 4%, but the rent roll's market rent column is stale.

A quick comp check suggests true loss to lease is closer to 2%.

Adjusted EGI is roughly $90,000 lower than the broker's reported number.

Minutes 7–10: Expenses

Insurance is trailing at $58,000.

A fresh quote in the submarket is closer to $84,000.

That is a $26,000 hit.

Taxes are underwritten flat at $215,000, but the proposed acquisition basis would put reassessment closer to $290,000.

Another $75,000.

R&M looks light at $380 per unit when comparable assets are running closer to $550 to $650 per unit.

Call that another $30,000 gap.

Adjusted operating expenses are roughly $130,000 higher than the T12.

Minutes 10–13: Debt and plan

At the proposed leverage and current rates, DSCR comes in at 1.18x on the adjusted NOI.

That is thin.

Debt yield is 7.9%.

Also thin.

The renovation plan assumes $250 per month rent premiums on light interior upgrades.

The comp set supports closer to $175.

Adjusting that pulls another $48,000 out of stabilized NOI.

Minutes 13–15: Stress and decision

Stress case: 60 bps of cap expansion, half the assumed rent growth, full tax reassessment in year one.

DSCR drops below 1.10x in year two.

The deal has no margin of error.

That does not mean the deal is dead.

It means the right answer is either a meaningfully lower price, probably closer to $28 million, or a pass.

Total time: 15 minutes.

Total clarity: enough to make the right call before wasting half a day on deeper modeling.

That is the value of speed.

Not rushing.

Focusing faster.

Where most of the time gets wasted

Here is the uncomfortable truth about how most underwriters spend their hours.

Task	Time lost	Value added
Cleaning the rent roll	High	Low
Cleaning the T12	High	Low
Mapping expense categories	High	Low
Fixing formatting errors	Medium	None
Hunting for missing assumptions	Medium	Low
Actual underwriting analysis	Low	High

The shift is the point.

Most underwriting time is preparation.

The actual analysis, the part that requires judgment, experience, and decision-making, is often the smallest slice of the day.

What 15 minutes cannot tell you

A 15-minute screen is powerful.

It is not magic.

The goal is not to replace full underwriting.

The goal is to avoid spending six hours underwriting a deal that should have been rejected in fifteen minutes.

A first-pass screen cannot replace:

lease audits
physical inspections
service contract review
environmental review
capital needs assessments
market interviews
lender diligence

Those things still matter.

What the screen does is tell you whether the deal deserves that level of attention in the first place.

A good first-pass underwrite does not tell you to buy the deal. It tells you whether the deal deserves another hour of your time.

Where technology fits

This is exactly the friction that pushed me to build MSA.

The slow part of underwriting was never the analysis.

It was everything before the analysis.

Messy rent rolls.

Inconsistent T12 formats.

Category mapping.

Manual cleanup.

The work nobody enjoys doing, but everyone has to do.

That is where tools like QuicRollAI, MSA Direct, MSA Analyzer, and MSA IQ fit best.

They shorten the path between:

“I received the files.”

and

“I have enough information to make a decision.”

QuicRollAI helps structure messy rent rolls and T12s.

MSA Direct moves the cleaned data into the underwriting workflow.

MSA Analyzer turns the cleaned data into a full underwriting model.

MSA IQ provides submarket data to help test rent assumptions, market context, and the story around the deal.

That is useful.

But the decision still belongs to the underwriter.

It always will.

Final takeaway

You do not need hours to underwrite a deal.

You need a better process.

Once the inputs are clean, the decision comes fast.

And the real job is not building the model.

It is asking the right question.

Does this deal still work when the assumptions get honest?

That is underwriting.

The 15 minutes is just what it looks like when the workflow stops fighting you.

FAQ

Can you really underwrite a deal in 15 minutes?

Yes, for a structured first-pass underwrite once the core inputs are clean and available. The 15 minutes is not full due diligence. It is the screen that tells you whether the deal deserves deeper analysis. Full investment committee underwriting, lease abstraction, and physical diligence still take days to weeks.

What is the difference between a 15-minute screen and a full underwrite?

A 15-minute screen tells you whether the deal is worth pursuing at the asking price. A full underwrite tells you whether to actually buy it. The screen catches obvious red flags: thin DSCR, aggressive rent assumptions, deferred capex, tax reassessment risk. Full underwriting validates every line item against primary documents, walks the property, abstracts the leases, and stress-tests the business plan against a wider range of scenarios.

What slows underwriting down the most?

File cleanup, inconsistent data formats, and manual category mapping. Most of the delay happens before the actual analysis starts. A messy rent roll and a non-standard T12 can turn a 15-minute screen into a 90-minute fight before any judgment gets applied.

How long does file cleanup actually take without the right tools?

On a clean broker package, 20 to 30 minutes. On a messy one, 60 to 90 minutes is common. Most of that time is reformatting and reconciling, not analyzing.

Do you need advanced Excel skills?

No. Advanced Excel can help, but the bigger advantage is having a repeatable workflow and clean inputs. A senior underwriter with a clean process and a structured template will always beat a junior with elaborate macros and a messy input file. The model is rarely the bottleneck.

What documents do you need for a 15-minute first-pass underwrite?

At minimum: rent roll, T12, purchase price or pricing guidance, basic debt assumptions, and an initial business plan thesis.

What is the most important step?

Normalizing revenue and expenses correctly. If those are wrong, the rest of the model is just clean math on bad inputs. The fastest underwriter in the world still loses money if the assumptions feeding the model are flattering instead of accurate.