Establish the terms.
Keep quoted numbers separate from estimates. Annual and monthly rates, expense stops and free-rent conditions each get their own treatment.
01 / Financial Model Builder
The asking rent is only the beginning.
Turn LOIs, emails and deal notes into an editable Excel model. The updated skill organizes offers and counters, separates TI allowances from rent credits, and keeps estimated expenses visible.
See it in practice Editable Excel workbook
Updated September 29Every scenario.
Every assumption.
Every assumption.
Comparison, summary, editable inputs
and monthly cash flow in one workbook.
Actual workbook included with the updated skill. Placeholder client names and illustrative USD economics. The two examples use different areas and terms; their totals are not a savings comparison.
Download the Excel example
What you bring
Start with the source.
- Current proposals or LOIs, with the offer dates and versions.
- Rentable area, term, rent schedule and concession conditions.
- Expense mechanics, accepted estimates, parking, buildout and TI terms.
What you receive
Work you can make yours.
- Scenario Comparison, followed by Summary, Assumptions and Monthly Cash Flow for each offer. September 29 skill update available to members.
- Editable inputs and formulas, with source references and clear rate units.
- A short explanation of the differences, exclusions and unresolved assumptions.
How the skill works
From source to review.
Build the monthly picture.
Lay out cash flows across the agreed horizon. Keep refundable deposits separate and distinguish a construction allowance from a rent credit.
Compare, then revise.
Inspect the scenario totals and monthly formulas. Update supported rate inputs; regenerate the schedule when the dates, term or structure change.
Both sides of the transaction
Built for the way you represent.
Support the client’s decision.
Compare renewal and relocation proposals on an explicit cost scope. Show your client why the lowest starting rent may lead to a different total cost.
Put the proposal in context.
Present the tenant-facing economics of alternative offers and counteroffers. Use a separately specified analysis for owner returns or property valuation.
Your final review
- Confirm the expense estimates and what is included in each proposal.
- Check TI eligibility, rent conversion and construction costs. The updated instructions require a TI and construction block after the base builder runs; the bundled example predates that block.
- The bundled calculation engine covers USD and full calendar months. Proration, complex caps, gross-up, pooled allowances and sublease recovery need separate verified analysis.
Can I edit the workbook?
Yes. The delivered workbook has editable inputs, monthly formulas and linked summaries. Structural changes such as a different term or commencement date require regeneration and reconciliation.
Can it use my existing model?
Provide your workbook and identify the controlling proposal. The workflow works on a copy, preserves the structure and flags anything that needs a separate calculation.
Does it calculate investment returns?
The released example is an occupancy-cost comparison. Owner returns, present value and sublease recovery require their own scope, assumptions and verification; they are not demonstrated by this workbook.
One membership. The complete library.
Start with the work
on your desk.
All five skills, versioned improvements and personal help getting set up. Bring a past deal you know well and make the workflow your own.
Currently supported in Claude. A separate compatible AI plan is required. The separate CoStar workflow is a member preview for ChatGPT Work; browser access, file tools and customer setup are required.