The verdict in three sentences
A hot-desking SaaS (3 to 8 EUR per user per month) is the right answer below 300 employees or to trial the model for 6 months. Beyond that, a custom app integrated with Microsoft 365 (25,000 to 45,000 EUR, about 27,000 to 49,000 USD, delivered in 10 to 14 weeks) becomes cheaper over three years and fits your team rules. Either way, the real gain comes from real estate savings: 10 to 30 % less space, worth hundreds of thousands of euros a year.
The financial lever: square metres
A company of 300 to 2,000 employees moving to 0.7 desks per person stops paying for empty desks on Mondays and Fridays. Office rents in 2026 range from about 220 EUR per m² per year in Lille to 550 to 650 EUR in central Amsterdam and well above that in the City of London. Each removed desk frees 10 to 12 m² of usable space. The table uses a conservative 220 EUR per m².
| Headcount | Desks at 1:1 | Desks at 0.7 | m² freed (11 m² per desk) | Annual saving at 220 EUR per m² |
|---|---|---|---|---|
| 300 employees | 300 | 210 | 990 m² | 217,800 EUR |
| 500 employees | 500 | 350 | 1,650 m² | 363,000 EUR |
| 800 employees | 800 | 560 | 2,640 m² | 580,800 EUR |
| 1,200 employees | 1,200 | 840 | 3,960 m² | 871,200 EUR |
| 2,000 employees | 2,000 | 1,400 | 6,600 m² | 1,452,000 EUR |
These are 2026 order-of-magnitude estimates: actual savings depend on your lease (early exit, subletting) and the share of common areas. Without a reliable booking tool, employees quickly revert to old habits and the project fails within 3 to 6 months.
SaaS or custom: the comparison
| Criterion | Hot-desking SaaS | Custom Microsoft 365 app |
|---|---|---|
| Upfront cost | 0 to 5,000 EUR of setup | 25,000 to 45,000 EUR |
| Annual cost for 800 users | 28,800 to 76,800 EUR | 5,000 to 9,000 EUR (hosting, maintenance) |
| Time to go live | 2 to 6 weeks | 10 to 14 weeks |
| Interactive floor plan | Yes, standard template | Yes, from your DWG or PDF plans |
| Team rules (office days, zones) | Limited | Unrestricted: quotas, team neighbourhoods, priorities |
| Outlook and Teams integration | Often an add-on | Native via Microsoft Graph |
| QR check-in and auto-release | Yes | Yes, configurable delay (e.g. 30 min) |
| Occupancy analytics | Standard dashboards | Power BI export, your own data |
A custom app typically includes desk and room booking from Teams, Outlook or mobile, an interactive floor plan, QR check-in with auto-release after 30 minutes, team rules, and an occupancy dashboard by floor and day. The Microsoft Graph connector accounts for 15 to 20 % of the budget, the interactive floor plan 20 to 25 %.
Mini case study
Nicolas, workplace director of an 800-employee insurer in Lille, occupies 9,500 m² at 220 EUR per m². A SaaS at 5 EUR per user would cost 48,000 EUR a year, or 144,000 EUR over three years. He chooses a custom app at 38,000 EUR plus 7,000 EUR of annual maintenance, 59,000 EUR over three years, saving 85,000 EUR versus the SaaS. After 6 months, measured occupancy peaks at 64 %, which lets him hand back a 1,800 m² floor: 396,000 EUR less rent per year. For a team in London or Amsterdam, the same floor would be worth two to three times more.
FAQ
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How long does a custom app take to roll out?
Allow 10 to 14 weeks: 2 weeks of scoping, 6 to 8 weeks of development, 2 to 4 weeks of pilot on one floor before full rollout.
Do we need occupancy sensors?
Not at first. QR check-in gives occupancy data that is more than 90 % reliable. Sensors (80 to 200 EUR per desk) are only justified for fine-tuning space beyond 1,000 desks.
Does the app work without Microsoft 365?
Yes, with Google Workspace or its own login. Microsoft 365 integration remains the most requested, as it lets staff book a room straight from Outlook.
How do we avoid ghost bookings?
With auto-release if no check-in happens within 30 minutes, and an advance-booking cap, for example 5 days maximum. These rules cut booked-but-empty desks by 20 to 30 %.
Is occupancy data GDPR compliant?
Yes if it is aggregated by floor and team for analytics, with a limited retention period for personal data, for example 3 months, and employee representatives informed.
Let's scope your project. Send us your headcount, number of floors and tools (Microsoft 365, Google Workspace): we will price the app, a one-floor pilot and rollout in 10 to 14 weeks. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
