How long does a new self storage store take to fill? What UK operators report

As at 16 October 2026 none of the operators we read states how long a new self storage store takes to fill to a given occupancy. Safestore, the only one whose results state a path for new stores, says they typically reach operational break-even towards the end of year 1, earnings break-even after financing at 18 to 24 months, and stabilisation usually five to six years from opening.

One supplier, PSL Limited, says to plan for 18 to 36 months to reach a stable occupancy of around 80 to 85%, and on 16 October 2026 its page named no source or sample for the figure. This guide is general information about what operators and one supplier report, not a forecast and not advice.

Big Yellow’s results show why one number misleads. At 31 March 2026 its 77 “same stores”, each of which had reached 85% occupancy in an earlier financial year, were 78.2% occupied by floor area. A second group of 12 stores, which this guide calls stores still filling, was 49.2% occupied.

A year earlier that group was 8 stores and 64.7% occupied. It grew to 12 stores while its occupied space rose, so the share occupied fell: a group average is not a store’s path.

How long does a new self storage store take to fill?

As at 16 October 2026 no operator we read states how long a new store takes to fill to a given occupancy. The nearest figures run from about 12 months (Safestore’s operational break-even) to five to six years (its stabilisation), and one supplier gives 18 to 36 months to reach 80 to 85% occupancy. Each counts something different.

Safestore, in its results for the year to 31 October 2025 and again in its interim results of 11 June 2026, describes a J-curve for new stores. Year 1 carries a fixed cost base while sales ramp up. Stores typically reach operational break-even towards the end of year 1, followed by rapid yield acceleration in years 2 to 5 as occupancy and rate move towards stabilisation. Neither set of results defines operational break-even (read 16 October 2026).

Safestore says stabilisation is usually five to six years from opening. It puts earnings break-even, after the cost of financing, between 18 and 24 months. Its sentence ties the 18 to 24 months to break-even, not to an occupancy level.

Valuation notes add two more clocks. Safestore’s and Big Yellow’s valuations each assume absorption, meaning occupancy rising to an estimated stabilised level, over years one to four (Safestore) or years one to five (Big Yellow) of the cash flow period. Big Yellow defines absorption as growth “from the current occupancy level to the assumed stable occupancy level”, which suggests these years run from the valuation, not from a store’s opening (our reading).

Safestore’s valuation note also says “the average time assumed for stores to trade at their maturity levels is 15.7 months” at 31 October 2025, and 18.5 months at 30 April 2026. On 16 October 2026 we found that the note does not say what the average is taken over or which maturity level it means, so we do not read it as a time to fill.

PSL Limited (Partitioning Services Limited) designs, makes and installs partitioning and mezzanine floors for self-storage facilities, so it is a supplier, not an operator. Its how-to page, dated 2 September 2025, says to plan for 18 to 36 months to reach a stable occupancy of around 80 to 85%.

Its construction costs page, dated 12 February 2026, uses a worked example at 85% occupancy and says new facilities typically take 18 to 24 months to reach that level. We found no source, sample or date range attached to either figure on those two pages (read 16 October 2026). That does not make either figure wrong; no operator we read publishes a time to a given occupancy to set beside them.

On 16 October 2026 we found no other expected fill-up curve in months for a new store in the results of Big Yellow, Lok’nStore or Shurgard. On 16 October 2026 we also found none in the Self Storage Association UK’s 2026 interactive report with Cushman & Wakefield, which this guide calls the SSA report. Big Yellow gives groups of stores at dates, Lok’nStore gave age bands, and Shurgard gives a target for stores it bought, not built.

What do mature and stabilised mean in each source?

Each source draws the line differently: by a store’s age, by an occupancy test, or by a valuation assumption. One source’s mature figure cannot stand in for another’s.

• SSA. The SSA report covers the 2025 operating year. It calls stores “not opened or expanded in the last four years” mature, and puts their occupancy at 79.6% of current lettable area, against 74.5% for all stores. That is an average for older stores, not a target (our reading).
• The SSA’s gap. The gap is 5.1 points (our calculation). The report says the gap between all-store and mature-store figures reflects “the dilution effect of new supply entering at lower initial fill rates”.
• Three printings. The same page prints the mature figure as 79.6% in its summary and text, as 80% in the text behind its third key-findings box, and as 79.1% on its “A decade of occupancy” tile. On 16 October 2026 we could not tell which of the three the SSA intends.
• Safestore, year to 31 October 2025. Across the group, its mature stores are over five years old (79% of maximum lettable area), its stabilising stores two to five years old (10%) and its non-like-for-like stores under two years old (11%). For its UK like-for-like portfolio it expects stabilised occupancy of 85% to 90%, against the 80.6% it achieved in its 2025 financial year.
• Safestore’s basis. Its occupancy is closing occupancy as a share of current lettable area, which leaves out space not yet fitted out and space that is operationally unavailable. Its valuation assumes stabilised occupancy averaging 89.0% at 31 October 2025 and 88.0% at 30 April 2026.
• Big Yellow, year to 31 March 2026. “Same stores” are those that “reached 85% occupancy during a previous financial year”: a test passed once, not a level held now. Its 77 same stores were 78.2% occupied at the year end, below the 85% that defines them.
• Big Yellow’s basis. Its occupancy is by floor area. Closing occupancy is occupied space over maximum lettable area at the balance sheet date, and average occupancy is the year’s average occupied space over that area. Its valuation assumes a stabilised 87% on average for its 113 trading stores.
• Lok’nStore, until 2024. Its annual report for the year to 31 July 2023 reported closing occupancy for stores over three years old, leaving out new space, and sorted stores by weeks old. Its valuer assumed stabilised occupancy of 87.79% on average for its 26 trading stores.
• Shurgard, results for 2025. Its release speaks of stores “not yet matured” and in ramp up. On 16 October 2026 we found no definition of mature in that release; the nearest is its chief executive linking non-mature stores to extra footage added in 2023, 2024 and 2025 and to the 2026 to 2028 pipeline.

Our reading: four years (the SSA), five (Safestore), three (Lok’nStore) and a one-off 85% test (Big Yellow) are four different lines. Check the definition before setting two figures side by side. Our UK self storage industry statistics page sets out the SSA’s wider figures, and our guide to self storage KPIs explains why a published figure is a range of what is possible, not a target.

What does a new store earn while it fills?

A store still filling earns a lower store margin than a settled one, and a newly opened store may not yet cover its own running costs.

In the year to 31 March 2026 Big Yellow’s 12 stores still filling together earned a store EBITDA margin of 58.5%, against 73.0% for its 77 same stores, a gap of 14.5 points (our calculation). In its results of 18 May 2026 it wrote: “All stores are trading profitably at the EBITDA level”, with the exception of a few newly opened stores.

Store EBITDA margin is store earnings before interest, tax, depreciation and amortisation as a share of store revenue. The 8 stores in the group a year earlier had earned 55.6%.

Revenue per available sq ft is total store revenue divided by average maximum lettable area. The stores still filling earned £23.82 per available sq ft against £34.99 for the same stores, or 68.1% (our calculation). Their average annual rate per occupied sq ft, which Big Yellow labels “net rent” per sq ft, was £34.04 against £38.45, or 88.5% (our calculation). Our reading: they charge close to the same rate per occupied sq ft but have far less of it occupied.

Lok’nStore showed the same shape by age. In the year to 31 July 2023 its store adjusted EBITDA margin was negative 24.4% for stores under 100 weeks old (about 23 months, our calculation), 51.7% for stores 100 to 250 weeks old and 59.8% for older ones, across 4, 3 and 19 stores. Its report says “Older stores have had more time to fill-up and produce higher EBITDA returns”.

Our reading: that first band holds four stores under about 23 months old, so it is not Safestore’s measure of a new store.

Lok’nStore’s interim results for the six months to 31 January 2024 gave adjusted EBITDA margins of negative 39.0%, 58.3% and 61.8%. On 20 July 2026 Big Yellow said it was beginning to see “discernible revenue contributions from the four stores recently opened”. Our guide to whether self storage is profitable covers what a mature store earns.

What path does a new store follow?

As at 16 October 2026, of the results we read, only Safestore states a path for a new store, its J-curve: operational break-even towards the end of year 1, then rapid yield acceleration in years 2 to 5. It is a path for earnings and yield, not a month-by-month occupancy line.

Safestore says the six stores it has opened since the end of its 2023 financial year are “performing in line with their expected maturity curve”. It says recently opened stores are on track for its 10% yield-on-cost hurdle, which is incremental EBITDA over the initial investment. On 3 September 2026 it said a significant proportion of its planned UK expansion was now delivered and “progressing through its occupancy ramp-up phase”.

Shurgard’s path is for stores it bought. It says average occupancy of the former Lok’nStore portfolio rose from 67% at acquisition in August 2024 to 80% in December 2025, and that it is “on track to achieve c. 90% occupancy by December 2026”. That is 13 points in 16 months (our calculation), for stores that were already trading, so it is not the path of a new store.

On 16 October 2026 we found no store-by-store occupancy path, one store month by month, in the results we read. A group’s path is not one store’s path.

The nearest measured pace is a group’s: Big Yellow’s eight stores still filling rose from 56.0% to 64.7% occupied in the year to 31 March 2025, 8.7 points, and 46,000 of the 48,000 sq ft of occupied space they added came in the first six months (our calculations from the table). On 16 October 2026 we found no ages for the eight stores, so this is not a new store’s first year.

Why does a group of new stores look worse than its parts?

A group average falls whenever a store emptier than the group joins it, even if every older store in the group is improving. Big Yellow’s tables show how.

Big Yellow’s Portfolio Summary splits its 113 stores into three groups, and two matter here: “same stores”, which passed an 85% occupancy test in an earlier financial year, and a group it labels “lease-up”. This guide leaves out the third group, of 24 stores. When a store moves group, Big Yellow re-presents the earlier year so that the store is in the same group in both years.

On 16 October 2026 we found no text in its documents that defines the second group other than by exclusion from the first. Our reading: it is the stores that had not reached 85% in an earlier financial year, and this guide calls it stores still filling.

Between 31 March 2025 and 31 March 2026 the group grew from 8 stores to 12. Big Yellow’s results text says the group added 60,000 sq ft of occupied space over the year.

Our calculation from the tables: the group’s lettable space rose from 552,000 to 848,000 sq ft, up 296,000 or 53.6%, while its occupied space rose from 357,000 to 417,000 sq ft, up 60,000 or 16.8%. The share occupied fell because space was added faster than it was filled.

Big Yellow opened four new stores in the year, adding 0.3 million sq ft, and says these openings are “the primary driver” of a 4.5 point fall in its closing occupancy across all its stores. Its like-for-like reconciliation leaves out 295,000 sq ft of lettable space, of which 38,000 sq ft was occupied, or 12.9% (our calculation).

Our reading, not Big Yellow’s: if the 295,000 sq ft left out is the four new stores, and they are the four added to this group, its eight older stores held about 379,000 of 553,000 sq ft at 31 March 2026, or 68.5%, up from 64.7% a year earlier. That is 417,000 less 38,000, over 848,000 less 295,000 (our calculation). On that reading the group’s average fell while its older stores rose.

The closing gap to the same stores widened from 16.2 points at 31 March 2025 (80.9% against 64.7%) to 29.0 points at 31 March 2026 (78.2% against 49.2%), while the gap on the year’s average occupancy stayed near 20 points: 20.2 (82.3% against 62.1%) then 20.5 (79.7% against 59.2%) (our calculations). Closing and average occupancy answer different questions, so say which one you quote.

The table sets the group out at five dates, each row as printed in the document named below it.

How long does it take from buying a site to opening?

At the Big Yellow pipeline sites below it takes years: the two that print both a purchase date and an opening date run 37 to 39 and 55 to 57 months from purchase to anticipated opening (our calculation). Big Yellow says planning consent alone can take “anything from eighteen months to three years”. These are its dates as printed on 18 May 2026:

• Old Kent Road, London (79,000 sq ft). Bought June 2022, application October 2023, consent May 2026: 47 months from purchase to consent, 31 of them after the application (our calculation). No opening date is printed at 18 May 2026.
• Leicester (58,000 sq ft). Bought June 2023, consent granted, opening anticipated early 2028: 55 to 57 months (our calculation, reading early as January to March).
• Leamington Spa (54,000 sq ft). Bought May 2024, construction commenced, opening anticipated summer 2027: 37 to 39 months (our calculation, reading summer as June to August).
• Coventry (58,000 sq ft). Bought April 2025, application November 2025, no consent printed at 18 May 2026: about 6 months of waiting (our calculation).

PSL says a typical project runs 9 to 18 months from first sketch to opening, in four phases: planning and design 2 to 4 months, securing approvals 3 to 6, site and groundwork 1 to 2, and main construction and fit-out 3 to 6.

The two are not like for like, because PSL gives a typical programme and Big Yellow one site’s actual dates. PSL’s approvals phase is 3 to 6 months, while Big Yellow’s Old Kent Road, the only one of the four sites to print both dates, took 31 months from application to consent (our calculation).

All four Big Yellow sites above are in England; we did not check Wales, Scotland or Northern Ireland. These months come before the first customer, so the fill-up clock above starts after them (our reading). Our guide to self storage site selection covers planning, and our guide to the cost to build self storage covers what the years of waiting cost.

Does a small or container site fill faster or slower?

On 16 October 2026 we found no source that measures how fast a container site or a small site fills. We searched the results of Big Yellow, Safestore, Lok’nStore and Shurgard, the SSA report and the two PSL pages for the word container near fill, ramp, stabilis, absorption, mature, break-even or months to.

The nearest passage is the SSA’s account of the occupancy fall: “Increased new supply, particularly from container operators, has expanded customer choice.” On 16 October 2026 we found that the passage gives no fill-up figure for container sites.

Big Yellow’s four pipeline sites above are planned at 54,000 to 79,000 sq ft each, so the pipeline months describe stores of that size. We do not know whether they apply to a smaller site.

Two points of arithmetic do apply (our reading). A site that adds units in batches lowers its occupancy percentage each time a batch of empty units arrives, as Big Yellow’s group did when it grew from 8 stores to 12. A site with few units moves in large steps, because each move-in is a bigger share of the total.

How should you read your own fill-up?

Read each store by its age, state the basis of every percentage, and keep a group’s line apart from each store’s line. This guide sets no fill-up target; it is a method.

1. Start the clock at opening. Record occupancy at each month end against the store’s age in months. Lok’nStore sorted its stores by weeks old and Safestore sorts its by years old.
2. Write the basis beside every figure. Say closing or average, floor area or units, and what it divides by: Big Yellow divides by maximum lettable area, Safestore by current lettable area, which leaves out space not yet fitted out.
3. Keep the group apart from the store. A group average falls when a new, emptier store joins it, so track each store’s own line too.
4. Read units let beside the percentage. Move-ins and move-outs show whether space is filling while new capacity holds the percentage down. Big Yellow counts customers taking a storage room, not units.
5. Note the opening month. Our reading: the seasons move a new store’s line too, as our guide to self storage seasonality shows for Big Yellow.
6. Compare like with like. A published group mixes stores of different ages at one date, so it is not a yardstick for one store’s first year.

On 16 October 2026 we found no UK source, in the documents we read, that measures days to let: the average time a vacant unit waits for a customer. Count it from your own records if you want it. Our guide to self storage KPIs sets out the three kinds of occupancy.

In StoreBay, the Occupancy report shows occupied units as a share of lettable units, with reserved units shown separately and never counted as occupied. StoreBay rebuilds the occupancy trend from the allocation history as at the end of each day, week or month, and can draw the previous period as a second line.

The trend starts at the earliest occupancy record StoreBay holds for the operator and draws nothing before it, so a site moved across from another system should check where its history begins. StoreBay’s Move-ins & move-outs report counts units, not customers, and leaves agreements brought in by a data import out of its move-ins. The CSV and PDF downloads of StoreBay’s Occupancy report add occupancy by floor area.

Questions to put to your adviser

These are questions, not answers. They depend on your site, your lender and your tax position, and this guide is general information, not advice.

• If the plan fills a store faster than Safestore’s stated path, what evidence supports the faster fill?
• What stabilised occupancy does the valuation assume for the store, and over how many years does it reach it?
• Which meaning of stabilised does the lender use: an age, an occupancy level or an income level?
• Does the loan set a covenant on occupancy or income by a date, and what happens if the store fills more slowly?
• How many months of cash does the plan need before earnings break-even after the cost of financing?
• If planning consent comes late, what does the purchase contract allow, and what does waiting cost?
• How are the early losses treated for tax?

Our guide to the self storage business plan shows where the fill-up curve sits in the financial model.

What does this guide not cover?

• A forecast. This guide sets no fill-up target and makes no forecast for any store.
• Costs, prices and returns. We did not study what a new store charges beyond Big Yellow’s group figures above. Our guides to the cost to build self storage and to whether self storage is profitable cover costs and returns.
• Planning rules. Big Yellow’s pipeline sites above are in England, and we did not check Wales, Scotland or Northern Ireland.
• Other operators and countries. We read Big Yellow, Safestore, Lok’nStore, Shurgard, the SSA report and two PSL pages, and no others.
• The SSA report in other formats. We read it as the interactive page it is published as, and we did not read a PDF edition.
• Lok’nStore after April 2024. We used no Lok’nStore figures after its interim results of 22 April 2024, because Shurgard bought its UK stores in August 2024.

Sources

All read on 16 October 2026.

• Big Yellow Group’s preliminary announcement for the year ended 31 March 2026, 18 May 2026.
• Big Yellow’s annual report and accounts 2025, for the year ended 31 March 2025.
• Big Yellow’s results for the six months ended 30 September 2025, 17 November 2025.
• Big Yellow’s Q1 trading statement, 20 July 2026, as copied on Investegate.
• Safestore Holdings’ final results for the year ended 31 October 2025, 15 January 2026.
• Safestore’s interim results for the half year ended 30 April 2026, 11 June 2026, and its third quarter trading update, 3 September 2026, both as held by the FCA National Storage Mechanism.
• The Self Storage Association UK’s 2026 interactive report with Cushman & Wakefield, covering the 2025 operating year.
• PSL Limited’s how to start a self storage business, 2 September 2025, and its self storage construction costs, 12 February 2026.
• Lok’nStore Group’s annual report and audited accounts for the year ended 31 July 2023, as hosted by Shurgard, and its interim results, 22 April 2024, as copied on Investegate.
• Shurgard Self Storage SA’s full year results 2025, 26 February 2026.