If you’re looking at commercial space for the first time, the headline rent is only part of the story. In the current UK market, base rent typically represents just 60% to 70% of your total occupancy cost. That remaining 30% to 40% — mostly made up of service charges, insurance, and business rates — is where many tenants get caught out. I’ve watched this pattern repeat for years: a business owner signs a lease based on the rent per square foot, only to discover the real monthly outlay is far higher once the service charge lands.
That gap between what you expect to pay and what you actually pay is the single biggest source of friction in commercial leasing. The good news is that a major update to the RICS Service Charge Standard came into force on 31 December 2025, bringing the most significant shift in service charge governance in nearly a decade. If you’re renting commercial space — or planning to — understanding how rent is calculated and what the new rules mean for your service charge is essential. Here’s what you actually need to know.
Before you sign anything, it’s worth getting a clear picture of the full lease structure. I’d recommend reading our guide on understanding public market lease agreements to see how these costs fit into the bigger picture. And if you’re worried about unexpected bills, a tenant landlord lawyer can review your lease before you commit — it’s a small upfront cost that can save you thousands.
How commercial rent is actually calculated
Most people assume commercial rent is a simple number. It’s not. Surveyors calculate it using a “per square foot” (psf) basis, but the measurement method matters. Net Internal Area (NIA) measures the usable office or retail space, excluding structural columns, lift shafts, and toilets. Gross Internal Area (GIA) includes everything within the external walls — that’s the standard for industrial warehouses and logistics hubs. For high-street shops, surveyors apply “Zone A” pricing, which assigns the highest value to the first 6.1 metres of depth from the shop window, since that area generates the most retail sales.
To verify your annual costs, use this formula: Total Square Footage x Rate per Square Foot. Divide by 12 to get your monthly figure. But remember — that’s just the base rent. The real cost includes service charges, insurance rent, and business rates. I always tell people to ask for a full cost breakdown before they even start negotiating. If a landlord hesitates, that’s a red flag. You can learn more about how these figures are set in our piece on understanding market rent in the UK.
Why the new RICS Service Charge Standard matters for you
The updated RICS professional standard, Service charges in commercial property, second edition, took effect on 31 December 2025. It’s compulsory for all RICS-accredited professionals, and while it doesn’t override your lease terms, it sets a benchmark for what’s considered reasonable. If your landlord or property manager is RICS-regulated, they must comply — or explain why they haven’t.
Here’s what changes for you as a tenant. Landlords must now issue service charge budgets at least one month before the start of the service charge year. Year-end accounts and reconciliations must be provided within four months of the year ending. If there’s any delay, the landlord has to explain why. The budget and reconciliation must include an apportionment matrix — a breakdown of total costs and how they’re weighted between occupiers. That’s a big step up in transparency.
Management fees can no longer be based on a percentage of the budgeted or actual service charge. They must now be fixed at the start of the service charge year. Any commission, rebates, or other payments received by the landlord or manager — for example, from buildings insurance — must be declared in the service charge accounts. The landlord can only keep that commission if it’s reasonable for work actually done.
Perhaps the most important change is the list of costs that can no longer be recovered through the service charge. These include landlord investment costs (like asset management and rent collection), void property costs (rates, insurance, and services for empty units), initial capital costs (original fit-out, new plant or equipment), future redevelopment costs, and negligence-related costs from poor maintenance. If your lease currently allows these, the Standard gives you a strong argument to push back. For more detail on how these rules apply to your specific situation, take a look at our essential guide to service charge agreements.
Where tenants get caught out
Even with the new Standard in place, there are common traps that catch tenants off guard. Here are the ones I see most often.
Not checking for a service charge cap
Many leases don’t include a service charge cap, which means your exposure to unexpected building repairs is unlimited. If the roof needs replacing or the lift breaks down, you could be billed for a share of the cost — even if you’ve only been in the building for six months. Always check for a “service charge cap” in the legal pack. If there isn’t one, negotiate for it. A cap limits your liability to a fixed percentage increase each year, giving you predictable costs.
Ignoring the insurance rent
Insurance rent is a concept where the landlord insures the entire building but recharges the premium to you. The problem? You have no control over which insurer they use or how much they pay. Under the new Standard, any commission the landlord receives from the insurance policy must be declared, but that doesn’t stop the base premium from being higher than what you could get yourself. Ask to see the insurance schedule and compare it to market rates. If it looks high, challenge it.
Overlooking business rates and the 2026 revaluation
Business rates are a tax paid directly to the local authority, and the next major revaluation is scheduled for 1 April 2026. That could mean a significant change in your bill, depending on where your property sits in the new valuation. Don’t assume the current rateable value will stay the same. Factor in a potential increase when you’re budgeting. You can check your property’s rateable value on the government’s website and appeal if you think it’s wrong.
Assuming rent reviews always mean an increase
Standard UK commercial leases typically follow a 3-to-5-year rent review cycle. A common misconception is that rent must always increase. In reality, the review assesses what a new tenant would pay for the premises on the open market at that exact date. If the market has dropped, your rent could stay the same or even decrease — though upwards-only clauses prevent that. The government’s proposed ban on upwards-only rent reviews, included in the English Devolution and Community Empowerment Bill published in July 2025, would change this. If enacted, it would make leasing fairer for tenants, especially on the high street. The Bill is currently at committee stage in the House of Lords, so watch this space.
To see how these mistakes play out in real negotiations, read our article on negotiating commercial leases in the UK — it covers the tactics landlords use and how to counter them.
→ Scroll right to see all columns
| Cost type | Recoverable under new Standard? | What to watch for |
|---|---|---|
| Landlord investment costs | No | Asset management, rent collection, reversionary interest |
| Void property costs | No | Rates, insurance, services for empty units |
| Initial capital costs | No | Original fit-out, new plant, improvement works |
| Negligence-related costs | No | Avoidable overspending, poor maintenance |
| Management fees | Yes (fixed only) | Must be fixed at start of year, not percentage-based |
| Insurance commission | Yes (with disclosure) | Must be declared; retained only if reasonable |
Your practical guide to renting commercial space in 2026
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Here’s the step-by-step approach I’d take if I were renting commercial space today. These actions are based on the new RICS Standard and the current market conditions.
Calculate your total occupancy cost before you view a property
Don’t look at the headline rent in isolation. Use the formula (Total Square Footage x Rate per Square Foot) to get the base rent, then add estimated service charges, insurance rent, and business rates. Ask the landlord or agent for the previous year’s service charge accounts and the current insurance premium. If they won’t provide them, walk away. A transparent landlord is a good sign. I’d also factor in a contingency of 10–15% for unexpected costs, especially in older buildings where maintenance issues are more likely.
Review the service charge budget and apportionment matrix
Under the new Standard, the landlord must provide a budget at least one month before the service charge year starts. Check the apportionment matrix — it shows how costs are split between occupiers. Make sure your share is fair and based on your actual floor area, not a flat percentage. If the building has empty units, check that their costs aren’t being passed to you. The new Standard explicitly prohibits recovering void property costs through the service charge, so push back if you see them.
Negotiate a service charge cap and fixed management fee
Even with the new Standard, your lease is the final word. If it doesn’t include a service charge cap, negotiate for one. A typical cap limits annual increases to 5–10% or the Retail Price Index, whichever is lower. Also confirm that the management fee is fixed for the year, not a percentage of the budget. If the landlord tries to include a percentage-based fee, point to the new RICS Standard and ask for it to be fixed. For more on negotiating lease terms, see our guide on negotiating rent-free periods — it’s a useful lever when you’re discussing the overall deal.
Understand the proposed ban on upwards-only rent reviews
The government’s English Devolution and Community Empowerment Bill, published in July 2025, includes proposals to prohibit upwards-only rent reviews in new and renewal commercial leases. If enacted, this would mean your rent could go down if the market drops — not just stay the same or increase. The Bill is at committee stage in the House of Lords, so it’s not law yet, but it’s worth knowing about. If you’re negotiating a new lease in 2026, ask your solicitor to include a clause that mirrors the proposed ban, so you’re protected if it passes. A business lawyer can help you draft this language.
Check the EPC rating and future energy efficiency requirements
By 2026, energy efficiency standards (MEES) will require many buildings to move toward an EPC rating of ‘B’ by 2030. If the property you’re renting has a low EPC rating, you could face higher energy costs and potential compliance issues down the line. Ask for the current EPC certificate and check when it expires. If the rating is below ‘C’, factor in the cost of potential upgrades — or negotiate a rent reduction to account for the risk. A property lawyer can advise on how to handle this in your lease.
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1Calculate total occupancy costBase rent + service charges + insurance rent + business rates + 10–15% contingency. Ask for previous year’s accounts.
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2Review the service charge budgetCheck the apportionment matrix and ensure void costs aren’t passed to you. Push back if they are.
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3Negotiate caps and fixed feesService charge cap (5–10% or RPI) and fixed management fee. Reference the new RICS Standard.
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4Address rent review clausesAsk your solicitor to include a clause mirroring the proposed ban on upwards-only reviews.
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5Check the EPC ratingAim for ‘C’ or above. Factor in upgrade costs if the rating is lower.
Frequently asked questions
Can my landlord charge me for empty units in the building? ▾
What happens if my landlord doesn’t follow the new RICS Standard? ▾
Can my rent ever go down at a rent review? ▾
What’s the difference between NIA and GIA, and why does it matter? ▾
Do I need a solicitor to review my commercial lease? ▾
The key takeaway is simple: don’t sign a commercial lease based on the headline rent alone. The new RICS Standard gives you more protection than ever before, but only if you know what to look for. Start by calculating your total occupancy cost, check the service charge budget and apportionment matrix, and negotiate a cap on your exposure. If the proposed ban on upwards-only rent reviews becomes law, future leases will be fairer — but for now, your lease is your only protection. Get it reviewed by a professional before you sign.
If this was useful, you might also want to read understanding anchor tenant lease terms for your business.
Sources and Further Reading
Tips for ensuring disabled access when renting commercial space — A practical guide to compliance and accessibility requirements for your business premises.
Negotiating commercial leases in the UK: secrets landlords don’t want you to know — Insider strategies for getting better terms and avoiding common pitfalls.
The new RICS Service Charge Standard: what it is and changes for 2026. Stevens & Bolton, 2025.
Commercial lease rent explained: the 2026 guide to UK business tenancies. Auction Property, 2026.
UK real estate sector 2026 and beyond. Charles Russell Speechlys, 2026.
