CAM Calculation Guide

How to Calculate the Annual CAM Reconciliation True-Up

The end-to-end formula and process for converting a year's GL data into a final CAM reconciliation statement with balance due or credit.

The annual CAM reconciliation is the process of comparing what a tenant actually owes in operating expense reimbursements to what they paid in monthly estimates throughout the year, then billing any remaining balance or issuing a credit. It is the culminating calculation in the CAM billing cycle and requires correctly applying every provision in the tenant's lease in the correct sequence: starting with actual GL expenses, then removing exclusions, applying gross-up if occupancy was low, applying caps on controllable expenses, multiplying by the tenant's pro-rata share, and finally subtracting total estimates paid to arrive at the balance due. Each step is order-dependent — applying caps before gross-up or gross-up after proration will produce incorrect results.

Formula

Balance Due (Credit) = (Annual Actual CAM × Tenant Pro-Rata Share) − Total Monthly Estimates Paid
[Where 'Annual Actual CAM' is after exclusions, gross-up, and cap adjustments]

Variables

NameSymbolDefinitionExample
Total Actual CAM ExpensesTACEThe sum of all actual GL operating expenses in the recoverable pool for the reconciliation year, after removing excluded items as defined in the lease.$1,350,000 total actual CAM after exclusions
Gross-Up AdjustmentGUAThe adjustment to variable expenses required when building occupancy fell below the gross-up threshold during the year. Applied before proration and before cap calculation.Gross-up increases effective pool from $1,350,000 to $1,420,000 (due to 82% average occupancy vs. 95% threshold)
Cap AdjustmentCAThe reduction applied to the tenant's controllable expense share when the growth of controllable expenses exceeds the lease cap percentage. Applied after gross-up, per tenant.Cap limits controllable share to $89,250 vs. actual $93,000 — $3,750 reduction
Tenant Pro-Rata SharePRSThe tenant's proportionate share fraction (Tenant RSF / Denominator SF) or the fixed percentage specified in the lease.7.5% (15,000 SF / 200,000 SF denominator)
Monthly Estimates PaidMEPThe total of all monthly CAM advance payments collected from the tenant during the reconciliation year. Includes any mid-year adjustments to estimate amounts.$7,500/month × 12 = $90,000 in estimates paid

Step-by-Step Process (6 steps)

1

Sum All Actual Expenses by Pool

Pull the GL trial balance or expense register for the reconciliation period and sum all line items in the recoverable CAM pool. Ensure expenses are on an accrual basis (not cash) to match the reconciliation period. This is the gross actual expense figure before any adjustments.

Example:

GL total for CAM pool accounts 5100–5499: $1,450,000 gross actual expenses.

2

Remove Excluded Expenses

Apply each exclusion defined in the tenant's lease: remove capital expenditures, management fee excess above the cap, depreciation, leasing commissions, tenant improvements, and any other lease-defined exclusions. Document each excluded amount with the GL account and dollar figure.

Example:

Gross $1,450,000 − CapEx $50,000 − depreciation $30,000 − management overage $20,000 = $1,350,000 recoverable pool.

3

Apply Gross-Up (if occupancy below threshold)

If the building's weighted average occupancy fell below the gross-up threshold during the year, apply the gross-up calculation to variable expenses only. This step increases the effective pool to a stabilized occupancy level.

Adjusted Pool = (Variable Expenses ÷ WAO × Threshold) + Fixed Expenses

Example:

Variable $900,000, Fixed $450,000, WAO 82%, threshold 95%: Adjusted pool = ($900,000 ÷ 0.82 × 0.95) + $450,000 = $1,042,683 + $450,000 = $1,492,683. (In this example gross-up applies; skip if WAO ≥ threshold.)

4

Apply CAM Cap to Controllable Expenses

For any tenant whose lease contains a CAM cap, segregate controllable and uncontrollable expenses from the adjusted pool, multiply by the tenant's pro-rata share, and apply the cap ceiling to the controllable portion. The uncontrollable portion passes through at actual.

Tenant Controllable = MIN(Actual Controllable × PRS, Cap Ceiling)
Tenant Uncontrollable = Actual Uncontrollable × PRS
Tenant Total = Tenant Controllable + Tenant Uncontrollable

Example:

After gross-up, controllable pool $950,000, uncontrollable $400,000. Tenant PRS 7.5%. Controllable share: $71,250. Cap ceiling: $68,500. Billed at cap: $68,500 + ($400,000 × 7.5% = $30,000) = $98,500.

5

Apply Tenant Pro-Rata Share

Multiply the adjusted (post-gross-up, post-cap) recoverable pool by the tenant's pro-rata share to get the tenant's annual CAM obligation. Confirm the pro-rata percentage per the lease and denominator definition.

Annual Tenant CAM = Adjusted Pool × Pro-Rata Share

Example:

(Where no cap applies): $1,350,000 × 7% = $94,500 annual tenant CAM.

6

Subtract Estimates Paid and Calculate Balance Due

Subtract the total monthly estimates collected from the tenant during the year from the annual tenant CAM obligation. A positive result is a balance due from the tenant; a negative result is a credit due back to the tenant. Issue the reconciliation statement with full workpaper support.

Balance Due = Annual Tenant CAM − Total Estimates Paid

Example:

$94,500 − $90,000 (12 × $7,500) = $4,500 balance due. Issue reconciliation statement with 30-day payment window per lease.

Worked Example

Scenario

Office tenant, 12,000 SF in 160,000 SF building (7.5% share). No gross-up required (building maintained 96% occupancy). No cap on controllable expenses. Monthly estimates: $7,500/month. Reconciliation year: 2025.

Inputs

VariableValue
Gross Actual Expenses$1,450,000
Less: CapEx Exclusions($50,000)
Less: Depreciation($30,000)
Less: Mgmt Fee Overage($20,000)
Recoverable Pool$1,350,000
Gross-Up RequiredNo (96% WAO > 95% threshold)
Tenant Pro-Rata Share7.5%
Annual Tenant CAM$101,250
Monthly Estimates Paid$7,500 × 12 = $90,000

Calculation

Recoverable pool: $1,450,000 − $100,000 exclusions = $1,350,000
Tenant share: $1,350,000 × 7.5% = $101,250
Estimates paid: $7,500 × 12 = $90,000
Balance due: $101,250 − $90,000 = $11,250

Result:

Tenant owes $11,250 at reconciliation ($0.94/SF additional above monthly estimates). The higher-than-estimated balance was driven by actual expenses exceeding the estimate basis — landlord should adjust 2026 monthly estimates to $8,438/month ($101,250 / 12) to avoid a large year-end true-up next year.

Common Mistakes

Applying adjustments out of sequence — gross-up must happen before proration; cap must be applied after gross-up and at the tenant level, not at the building pool level.

Forgetting to remove excluded expenses before grossing up, which inflates the gross-up calculation on expenses that shouldn't be in the pool at all.

Using cash-basis GL data for reconciliation instead of accrual-basis, which can shift expenses between reconciliation years.

Not sending the reconciliation statement within the deadline specified in the lease — many leases have a 12-month window to send statements, after which the landlord waives the right to collect additional amounts.

Setting the following year's monthly estimates to the same amount as the prior year rather than adjusting to the current year reconciled actual, perpetuating a systematic under- or over-collection.

Issuing the reconciliation without supporting workpapers, which gives tenants no basis for verification and triggers audit requests.

When to Use This Calculation

  • Once per year for every commercial tenant, typically within 90–180 days after the end of the calendar year or lease year.
  • When preparing the annual CAM reconciliation statement to send to tenants.
  • When auditing a CAM statement received from a landlord, to follow the correct calculation sequence and verify each step.
  • When onboarding a new property to a management system, to establish the baseline calculation methodology for all existing tenants.

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