Pro Rata Share Adjustment Calculator

Remeasurement and vacancy carve-outs reshape tenant CAM shares.

Tenant SF

Current denominator SF

Adjusted denominator SF

Annual CAM

Annual CAM dollar impact

$28,571

Current share

0.060%

Adjusted share

0.071%

How the math works

Share = tenant SF / denominator. Impact = (adjusted share − current share) × CAM.

15k / 250k = 6% → 15k / 210k = 7.14%. × $2.5M CAM = $150k → $178.5k. +$28.5k annual impact.

How to Use

Enter tenant SF.
Enter current building denominator.
Enter adjusted denominator (post-remeasure).
Enter annual CAM.
Read share change and dollar impact.

Frequently Asked Questions

Why does denominator change?

Building remeasurement (BOMA updates, re-floored spaces), vacant-space carve-outs (some leases exclude vacant SF from denominator, concentrating cost on occupied tenants), common-area reclassifications, and new construction additions.

Impact on tenants?

Lower denominator = higher share = more CAM owed. Vacant-space carve-outs shift expense to occupied tenants, punishing them for landlord leasing failures. Tenant-favorable lease language includes a 'gross-up to 95% occupancy' clause to limit this.

Negotiation tips?

Lock the denominator in the lease. Require landlord notice and consent for changes. Cap annual share increases. Include gross-up language. Require itemized allocation method disclosure. Small tenants rarely get these; anchor tenants always do.