How do you calculate net operating income in real estate?

Calculate NOI in six steps: (1) Sum all base rent from active leases. (2) Calculate recovery revenue — CAM billed, tax recovery, insurance recovery. (3) Add percentage rent and other income. (4) Sum all operating expenses — CAM incurred, taxes, insurance, management fee, non-recoverable costs. (5) Subtract total expenses from total revenue. (6) Verify your recovery ratio (recovery revenue ÷ expenses incurred) against your lease-weighted theoretical maximum. Most operators stop at step 5, which is why NOI is often understated — step 6 reveals unbilled recovery that should have appeared in step 2. A recovery audit before finalizing NOI can add 3-8% to the revenue figure on properties with billing gaps.

What do you need to calculate NOI for a commercial property?

You need four data sources: (1) rent roll — all active leases with square footage, base rent rates, and lease terms; (2) operating expense ledger — all costs incurred and how they're categorized (recoverable vs. non-recoverable, capital vs. operating); (3) CAM recovery billings — what you've actually invoiced tenants for expense recoveries; and (4) lease abstracts — to confirm which expenses are recoverable, which are excluded, and whether caps or stops apply. The mismatch between items 2 and 3 — expenses incurred versus recovery billed — is the recovery gap. On most properties, this gap exists and is discoverable without major effort. The [cam-reconciliation](/resources/what-is-cam-reconciliation) process reconciles these two data sources annually.

Can I calculate NOI without CAM recovery data?

You can calculate a partial NOI using base rent only — but it will understate true NOI for any property with expense recovery provisions. Base rent NOI (rent minus non-recoverable expenses and management fee) is a valid sub-metric but it's not property NOI. Many CRE investors use base rent NOI as the floor: the value you'd have if recovery machinery completely failed. True NOI adds the net recovery margin on top. For properties with strong NNN leases and no CAM management complexity, the difference is small. For retail centers and office buildings with gross lease components, the difference can be 15-25% of total NOI.

How do you normalize NOI for occupancy when calculating property value?

Stabilized NOI adjusts for current vacancy by projecting NOI at the property's stabilized occupancy — typically 93-95% for retail, 90-92% for office. The adjustment has three parts: (1) add projected rent for vacant spaces at market rates; (2) adjust management fee to reflect higher revenue; (3) adjust recovery ratio — at higher occupancy, the gross-up provision applies less aggressively, so recovery improves. Do not apply the full market rent for vacant spaces — apply a lease-up period discount (typically 6-18 months of free rent plus TI costs amortized). The difference between as-is NOI and stabilized NOI is the upside underwriting: it tells you how much value creation is available through lease-up.

How does property tax affect NOI calculation?

Property taxes hit NOI twice — as an expense and as recovery revenue. In the expense column, the full tax bill reduces NOI. In the revenue column, tax recovery from tenants increases NOI. For NNN leases, 100% of taxes pass through and the net impact on NOI is zero. For gross leases, the landlord absorbs taxes directly — a meaningful NOI cost in jurisdictions with rapidly rising assessments. The [2026-property-tax-increases](/blog/2026-property-tax-increases) post covers how recent assessment increases are hitting property NOI in key markets. When underwriting, model property taxes forward using the assessment year cycle for the jurisdiction — don't assume flat taxes.

How to Calculate Net Operating Income in Real Estate

By Angel Campa·Founder, CapVeriUpdated April 24, 2026

Quick Answer

To calculate NOI for commercial real estate: sum all revenue (base rent + CAM recovery + tax and insurance recovery + other income), subtract all operating expenses (CAM costs incurred + taxes + insurance + management fee + non-recoverable maintenance), and verify your recovery ratio matches your lease entitlements. Most operators find 2-5% of NOI sitting in unbilled recoveries during their first reconciliation audit.

You can calculate a rough NOI in an afternoon using rent roll and expense ledger. Getting to accurate NOI — the kind that holds up under buyer due diligence — takes knowing where the recovery gaps are and how occupancy affects the calculation.

Here's the complete process.

Step 1: Pull Your Revenue Inputs

Start with the rent roll. You need:

Tenant name and lease dates (start, end, any options)
Leased square footage
Base rent — scheduled rate per the lease, not asking rent or market rate
Percentage rent provision — rate and breakpoint, if applicable
Recovery type — which CAM pool, any exclusions, any caps

Build a row per tenant. The totals give you base rent and the recovery allocation framework.

Example rent roll summary (60,000 sf strip center, 95% occupied):

Tenant	SF	Base Rent/sf	Annual Base Rent
Anchor	22,000	$13.00	$286,000
Co-anchor	10,000	$19.50	$195,000
Inline (7 tenants)	25,200	$28.75	$724,500
Total	57,200		$1,205,500

Vacant: 2,800 sf (4.7%) — no base rent contribution.

Step 2: Calculate CAM Recovery Revenue

This step is where most operators leave money on the table.

Sub-step 2a: Establish the CAM expense pool

Pull all operating expenses for the year and categorize:

Recoverable (goes into CAM pool for billing)
Excluded per lease (capital items, anchor exclusions, above-pool costs)
Non-recoverable (landlord absorbs, doesn't bill)

For this property: $318,000 total CAM expenses incurred, $290,000 billable pool ($28,000 excluded — parking lot repaving capitalized, and anchor's management fee exclusion).

Sub-step 2b: Calculate each tenant's pro-rata share

Pro-rata = Tenant SF ÷ Total Denominator SF

Denominator depends on the lease — some use total GLA, some use only occupied space, some use a fixed denominator. Check each lease.

For this example, denominator = total GLA (60,000 sf):

Anchor: 22,000 ÷ 60,000 = 36.67%
Co-anchor: 10,000 ÷ 60,000 = 16.67%
Inline avg (each): ~3,600 sf ÷ 60,000 = 6.0%

See pro-rata-share-calculation for denominator variations and how to handle mid-year changes.

Sub-step 2c: Apply any caps

Check whether each tenant's CAM cap is binding this year. A 5% cumulative cap from a $3.80/sf base year (Year 3):

Cap ceiling: $3.80 × 1.05³ = $4.40/sf
Actual CAM this year: $290,000 ÷ 60,000 = $4.83/sf
Cap applies: tenant pays $4.40 instead of $4.83

Track which tenants have binding caps. The aggregate shortfall from capped tenants reduces your effective recovery ratio. See cam-cap-types for the full cap structure taxonomy.

Sub-step 2d: Apply gross-up if permitted and applicable

At 95.3% occupancy, gross-up barely applies here. But if occupancy were 78%, the gross-up adjustment could add 5-8 percentage points to the billable pool. Method: Billable Pool ÷ Actual Occupancy % × Gross-Up Target % (usually 95%). See cam-gross-up-calculation-guide.

CAM Recovery Calculation Result:

Tenant	Pro-Rata Share	Max CAM Billable	Cap Applies?	CAM Billed
Anchor	36.67%	$106,367	Yes ($4.40 cap)	$96,800
Co-anchor	16.67%	$48,367	No	$48,367
Inline (avg)	6.0% × 7	$17,400 each	Varies	$15,800 avg
Total		$290,000		$255,934

Recovery ratio: $255,934 ÷ $290,000 = 88.3%

The anchor's cap is driving 11.7% of unrecovered CAM. At current expense levels, the anchor cap costs $29,567/year in unrecovered cost. As costs rise, this gap grows — the cam-cap-rate-multiplier shows how cap binding accelerates over time.

Step 3: Add Tax and Insurance Recovery

For most retail leases, these are 100% passable with no cap or exclusion:

Property tax bill: $195,000 → billed in full → $195,000 recovery
Insurance premium: $42,000 → billed in full → $42,000 recovery

Cross-check: confirm each lease explicitly includes taxes and insurance as recoverable. Some older leases have expense stops that cap landlord contribution at a base year amount, above which tenant pays. For this example, all leases are NNN-style on taxes and insurance.

Step 4: Add Percentage Rent and Other Income

Percentage rent: Anchor's lease has a 1.5% rate. Natural breakpoint = $286,000 ÷ 0.015 = $19,067,000. At $14M in anchor sales, no trigger — percentage rent = $0.
Parking lot (reserved spaces): $8,400/year
ATM income: $3,600/year

Other income: $12,000

Step 5: Total Revenue

Revenue Line	Amount
Base Rent	$1,205,500
CAM Recovery	$255,934
Tax Recovery	$195,000
Insurance Recovery	$42,000
Other Income	$12,000
Effective Gross Income	$1,710,434

Step 6: Operating Expenses

Expense	Amount
CAM (incurred)	$318,000
Property Taxes	$195,000
Insurance	$42,000
Management Fee (4%)	$68,417
Non-Recoverable Repairs	$22,000
Legal/Admin	$15,000
Total	$660,417

Step 7: Calculate NOI

NOI = $1,710,434 − $660,417 = $1,050,017

At 7.0% cap rate: $15.0M implied value

Recovery ratio: 88.3% (CAM); 100% (taxes, insurance)

Step 8: Verify Against Lease Entitlement

This is the step most operators skip. Compare actual recovery ratio to theoretical maximum — the recovery rate if every billable dollar were billed correctly, before caps.

For this property:

Theoretical max (ignoring caps): $290,000 ÷ $290,000 = 100%
After caps (anchor): 88.3%
Gap attributable to billing errors vs. lease structure: ~1-2% (estimated)

If the gap between theoretical and actual is larger than the cap impact, you have billing errors — unbilled recoveries that should have been invoiced. On this property: 88.3% actual vs. 89.5% theoretical-after-caps = 1.2% gap. At $290,000 pool, that's $3,480 in missed billing. Small, but real.

The cam-reconciliation-errors post covers the 12 most common sources of these gaps. The recovery-ratio-analysis framework shows how to benchmark your ratio against property type comps.

Occupancy-Normalized NOI

For the 2,800 sf of vacancy: what does NOI look like at full occupancy (97.5%)?

Additional base rent at $28.75/sf (inline rate): $80,500
Additional management fee: $3,220
Additional CAM billing (2,800 sf at current rates, assuming new tenant has standard lease): ~$14,000
Net NOI addition: $80,500 + $14,000 − $3,220 = ~$91,280

Stabilized NOI: $1,050,017 + $91,280 = $1,141,297

Stabilized value at 7.0% cap: $16.3M — vs. $15.0M as-is. The $1.3M gap is your lease-up value creation target.

For the full occupancy normalization methodology, including free rent periods and TI cost offsets, see noi-calculation-example.

Common Calculation Mistakes

Mistake 1: Using collection-basis CAM instead of accrual

If you had $50,000 in Q4 CAM true-ups uncollected at year-end, your cash NOI understates your accrual NOI. For property valuation, use accrual-basis recovery revenue (what you're entitled to bill, not just what's been paid). Then track AR aging separately.

Mistake 2: Including non-operating income above the NOI line

Tenant improvement allowance reimbursements, insurance proceeds, and lease termination fees are not operating revenue. Including them in NOI overstates it. Put them below the NOI line or in a separate capital events section.

Mistake 3: Netting management fees against recovery

Some operators reduce CAM recovery billings by the management fee rather than booking the fee separately as an expense. This understates both revenue and expense, but misrepresents the recovery ratio and distorts comparability.

Mistake 4: Using average occupancy instead of period-specific

If occupancy was 98% in Q1-Q3 and dropped to 85% in Q4 due to a major tenant departure, annual average is 95.25%. But your Q4 CAM billing used the wrong denominator for 3 months. Recalculate recovery quarterly or monthly for accuracy.

Using the NOI Impact Calculator

Once you have the NOI baseline, model improvement scenarios using the NOI impact calculator:

Input current vs. target recovery ratio
Set CAM pool size
Input cap rate
Get: annual NOI gain and implied value gain from the improvement

This turns the abstract NOI formula into an actionable management target.

For more worked examples across different property types, see noi-calculation-example. For how these numbers feed into property valuation, see noi-to-value-commercial-property and cap-rate-noi-relationship-cre.