Office Space Needs Calculator
Find how many square feet you actually need — 18-month growth included — before you sign for too much or too little.
Written by Dorothy Ibrahim, 10+ years in banking & finance
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How we calculate this
This calculator right-sizes your office before you sign a lease: how many square feet your team needs — including the hires you expect over the next 18 months — and what that space will cost per year and per employee. It works from rule-of-thumb space-per-person figures by layout (roughly 125 sq ft/person open plan up to 225 sq ft/person for mostly private offices) plus your shared space, so you avoid both an expensive mid-term re-lease and the more common mistake of over-leasing.
The formulas
- People to plan for
- current headcount + hires expected in the next 18 months
- Recommended square footage
- people to plan for × square feet per person (by layout) + shared space square feetSquare feet per person: open plan 125, mostly private offices 225, mixed = the midpoint, 175 — all rules of thumb.
- Layout range (low–high)
- low = people × 125 (open plan) + shared space; high = people × 225 (private offices) + shared space
- Projected annual rent
- recommended square footage × target rent per sq ft per year
- Cost per employee per year
- projected annual rent ÷ people to plan for
Worked example
- Say you have 10 people today, expect 4 hires within 18 months, want an open-plan layout, need 400 sq ft of shared space (conference, kitchen, reception), and are targeting $30/sf/yr rent.
- People to plan for = 10 + 4 = 14.
- Recommended space = 14 × 125 sq ft + 400 = 2,150 sq ft; across layouts the range runs 2,150 (open plan) to 14 × 225 + 400 = 3,550 sq ft (private offices).
- Projected annual rent = 2,150 × $30 = $64,500/yr.
- Cost per employee = $64,500 ÷ 14 = $4,607.14/yr per planned seat.
- At $30/sf, every extra 500 sq ft you over-lease costs $15,000/yr — the tool surfaces that number so "a little breathing room" gets priced before you sign.
Rates, benchmarks & sources
- Square feet per person: ~125 open plan, ~225 mostly private offices, ~150–250 overall band; mixed layout uses the 175 midpoint — Industry rule of thumb (space-planning convention, not a standard)
Figures current as of 2026-07-02. See our methodology & editorial standards for how constants are versioned and verified.
What this tool doesn’t model
- All space-per-person figures are rules of thumb — actual needs depend on your floor plate, building efficiency, and how your team works; a space planner or architect refines this for a specific building.
- It does not model hybrid or remote schedules — if only part of the team is in on a given day, desk-sharing can roughly halve the per-person figure, and the tool leaves that adjustment to you.
- Rent is a single $/sf/yr figure: NNN pass-throughs, escalations, free rent, and buildout are outside this tool — price a specific space with the Commercial Lease Cost calculator.
- Headcount growth beyond 18 months is not modeled; fast-growing teams may need expansion rights or shorter terms rather than more square footage today.
- Usable vs rentable square footage is not distinguished — buildings quote rentable area that includes a load factor for common areas, so the space you can actually lay out is smaller than the number on the lease.
Frequently asked questions
How many square feet per employee do I need?
As a rule of thumb, roughly 150–250 sq ft per person overall: about 125 sq ft/person for a dense open plan, around 175 for a mixed layout, and about 225 where most people have private offices. These figures include a share of circulation space but not large shared rooms, which is why the tool adds conference, kitchen, and reception space separately. Treat the result as a planning range, not a precise answer.
Why should I plan for headcount I have not hired yet?
Because a lease outlives your current org chart. If you sign for exactly today’s team and grow into the space in year one, your options are subleasing extra space elsewhere, an expensive early exit, or cramming — all worse than planning ahead. The tool adds your expected 18-month hires to the sizing so the space fits the team you will have mid-term, not the one you had at signing.
What does over-leasing actually cost me?
Every extra square foot is rent on space that produces nothing, paid every year of the term. The tool prices it directly: at the default $30/sf, an extra 500 sq ft is $15,000/yr — $75,000 over a 5-year lease. Over-leasing is the most common space mistake precisely because it feels harmless at signing; seeing the annual number attached to "room to grow" keeps the buffer deliberate instead of accidental.
How should hybrid or remote work change the answer?
Substantially — the per-person figures assume everyone has a seat every day. If your team splits days in office and shares desks, a common starting point is to halve the per-person square footage, then add back any extra collaboration space you need for the days everyone overlaps. The tool does not model attendance patterns itself, so run it with an adjusted effective headcount and sanity-check against your busiest planned day.
Is the recommended square footage usable or rentable space?
The tool sizes the space you actually need — closest to usable area. Landlords, though, quote and charge on rentable square footage, which adds a load factor for lobbies, corridors, and shared restrooms. That means the space you lease will typically need to be somewhat larger on paper than the tool’s figure to deliver the same working area. Ask any landlord for both numbers, and use the rentable figure when projecting rent.
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themoneysheet provides educational estimates, not financial, tax, or legal advice. Figures use published rates and formulas current as of the date shown, but your situation may differ. Consult a qualified professional (CPA, attorney, or licensed advisor) before making financial decisions. Rates shown are estimates; actual offers depend on lender underwriting.