Direct Answer
Same-store sales, also called comparable-store sales or comps, is the percentage change in sales at stores that have been open for a comparable period, typically at least one year, in both the current and prior periods, excluding sales from newly opened or closed locations. The metric exists to answer one specific question: is the retailer's existing store base selling more or less than it did a year ago, independent of how many new stores it has opened or closed?
Retailers report same-store sales, usually quarterly and annually, alongside total revenue because total revenue on its own conflates two very different sources of growth: expansion (opening new locations) and organic demand (existing stores selling more to the same or similar customer base). A retailer can post strong headline revenue growth almost entirely from new-store openings while its existing stores are flat or shrinking, same-store sales is the figure that isolates that difference.
Key Takeaways
- Same-store sales isolates organic growth. It measures the sales change in a retailer's existing store base, excluding stores that opened or closed during the comparison window, so it separates demand-driven growth from expansion-driven growth.
- Also called comparable-store sales or comps. The terms are used interchangeably across earnings releases, analyst commentary, and financial media.
- A store typically needs at least one year of operating history in both the current and prior periods before it is included in the comparable-store base, this threshold is commonly cited, not fixed by a single accounting standard.
- It is not a GAAP-defined metric. Exactly which stores qualify, the length of the qualifying window, and whether e-commerce sales are folded in all vary by retailer.
- Cross-retailer comparisons need care. Because methodology is not universal, two retailers' reported same-store sales percentages are not automatically apples-to-apples without checking how each defines its comparable-store base.
How Same-Store Sales Is Calculated
The core calculation compares sales at the same set of stores across two periods:
Same-Store Sales Growth (%) = (Comparable-Store Sales, Current Period − Comparable-Store Sales, Prior Period) ÷ Comparable-Store Sales, Prior Period × 100
The two inputs on the right side of the formula are not total company sales, they are sales generated only by the subset of stores that qualify as "comparable" in both periods. A store enters the comparable-store base once it has been open for a comparable period, typically at least one year, in both the period being measured and the period it is being measured against. A store that opened six months ago has no true prior-period baseline yet, so it is excluded from the comparison until it has enough operating history in both windows.
The same logic applies to closed locations: if a store that was open and selling in the prior period has since closed, its prior-period sales are excluded from the comparable base rather than counted as a decline, because there is no current-period figure from that location to compare it against. What remains after these exclusions is a like-for-like set of stores, which is what makes the resulting percentage a measure of organic performance rather than a byproduct of network expansion or contraction.
Because the definition of "comparable period" and the treatment of remodeled, relocated, or temporarily closed stores are not standardized by GAAP, retailers disclose their own methodology, typically in the MD&A section of quarterly and annual filings, so investors comparing figures across companies should read that disclosure rather than assume identical treatment.
Worked Example, Hypothetical, for education only
Assume a retail chain operated 500 total stores at the end of the current fiscal quarter, of which 480 stores had been open for at least one year and therefore qualified as comparable stores in both the current and prior-year quarters. The remaining 20 stores were newly opened during the past year and are excluded from the comparable-store base.
- Prior-period comparable-store sales: the 480 qualifying stores generated $1.20 billion in sales during the prior-year quarter.
- Current-period comparable-store sales: those same 480 stores generated $1.26 billion in sales during the current quarter.
- Apply the formula: ($1.26B − $1.20B) ÷ $1.20B × 100 = $0.06B ÷ $1.20B × 100 = 5.0%.
- Interpretation: the retailer's existing store base grew sales 5.0% year over year. If total company revenue grew faster than 5.0% for the quarter, the difference is attributable to the 20 new stores rather than to stronger performance at existing locations.
This hypothetical isolates a single, clean input set. In practice, retailers must also make and disclose judgment calls, for example, how a remodeled or relocated store within the same trade area is treated, or whether a store closed briefly for renovation stays in the comparable base, decisions that can shift the reported percentage by a meaningful amount without any change in underlying demand.
Limitations and Common Mistakes
Treating same-store sales as a standardized, audited figure
Same-store sales is not defined or required by GAAP. Each retailer sets its own rules for what counts as a comparable store, how long a store must operate before qualifying, and how it handles edge cases like remodels, relocations, or temporary closures. Because the methodology is not universal, a single retailer's reported number should generally be evaluated against its own historical trend and disclosed methodology, not treated as a precise, standardized industry figure.
Comparing two retailers' comp numbers without checking definitions
Because treatment of e-commerce sales, store-qualification windows, and remodel handling varies by retailer, two companies reporting similar same-store sales percentages are not necessarily describing equivalent underlying performance. Reading the methodology note in each company's filing before drawing a cross-company conclusion avoids this mistake.
Ignoring whether e-commerce is included
Whether online sales, either attributed to a physical store or reported through a separate digital channel, are folded into the comparable-store figure varies by retailer. Two retailers with identical in-store performance can report different comp percentages purely because of how each defines the scope of what counts as a comparable sale.
Missing calendar and cannibalization effects
Same-store sales figures can be distorted by calendar factors such as a shifted holiday period or a fiscal year with an extra week, since these change the comparability of the two periods being measured even among genuinely comparable stores. Same-store sales can also decline at existing locations because a retailer opened a new store nearby that pulls sales from the older one, a form of cannibalization that lowers comps even as the retailer's total sales in that market grow.
Assuming the metric explains why sales changed
Same-store sales growth or decline is used to isolate organic sales performance from new-store growth, but the figure itself does not explain the cause. Positive or negative comps can reflect foot traffic, pricing, unit volume, promotional activity, competitive pressure, or macroeconomic conditions, the metric flags the direction and magnitude of change in the existing store base, not the underlying driver.
FAQ
What is the difference between same-store sales and total revenue growth?
Total revenue growth includes sales from every store a retailer operates, including newly opened locations and any stores that closed during the period. Same-store sales growth excludes those new and closed locations, isolating the percentage change in sales at stores that have been open for a comparable period, typically at least one year, in both the current and prior periods. A retailer can show strong total revenue growth driven mostly by opening new stores while its existing store base is flat or declining, same-store sales is the metric that surfaces that distinction.
Why do retailers exclude new and closed stores from same-store sales?
Excluding newly opened or closed locations is what allows same-store sales to isolate organic sales growth or decline in a retailer's existing store base from growth that comes purely from opening new stores. A newly opened store typically has no prior-period sales to compare against, so including it would inflate the growth figure with expansion rather than demand. Removing new and closed stores from the comparison keeps the metric focused on whether existing locations are selling more or less than they did a year earlier.
Is same-store sales a GAAP-defined metric?
No. Same-store sales, also called comparable-store sales or comps, is a commonly cited retail industry metric rather than a figure defined or standardized by GAAP. Exactly which stores qualify as "comparable," how long a store must be open before it enters the base, and whether e-commerce sales are included all vary by retailer. Because the methodology is not universal, comparing the same-store sales percentages of two different retailers directly can be misleading without checking how each company defines its comparable-store base.
How long must a store be open to count in same-store sales?
A store generally needs to have been open for a comparable period in both the current and prior periods being measured, typically at least one year, before it is included in the same-store sales base. This threshold is commonly cited rather than fixed by any single accounting standard, so the exact cutoff a retailer uses can vary. Once a store crosses that threshold, its sales become eligible to be included in both the current-period and prior-period comparable-store totals.
Does same-store sales include online sales?
It depends on the retailer. Whether e-commerce revenue attributed to a physical store, or a company's direct online channel generally, is folded into the comparable-store sales figure varies by retailer and has become a more significant methodological question as omnichannel retail has grown. Because there is no single required treatment, investors comparing same-store sales figures across companies should check how each retailer defines what counts as comparable-store sales before treating the numbers as directly comparable.
What does positive or negative same-store sales growth indicate?
Positive same-store sales growth indicates that a retailer's existing store base is generating more sales than it did in the comparable prior period, which is commonly read as a sign of organic demand strength independent of new-store expansion. Negative same-store sales growth indicates the existing store base is generating less sales than before, which can point to declining foot traffic, weaker consumer demand, increased competition, or cannibalization from the retailer's own new stores or online channel, the specific cause is not determined by the metric itself and generally requires further analysis.
What is a two-year stacked comparable sales figure?
A stacked comp adds the current period growth rate to the same period a year earlier, producing a cumulative figure across two years. It exists because a single comp is measured against whatever happened in the prior year, so a weak prior period flatters the current one and a strong prior period penalizes it. Stacking removes some of that base effect. It is an approximation rather than a compounding calculation, and it becomes less meaningful the further apart the two periods are in conditions.
How does a 53-week fiscal year affect a comparable sales figure?
Most retail calendars run in four and five week blocks, which drift against the calendar year, so roughly every five or six years an extra week is added. That extra week adds revenue to total sales but is normally excluded from the comparable base, since including it would compare 53 weeks against 52. Companies usually state the effect. Missing the adjustment produces an apparent growth jump in one year and an apparent decline in the next.
Do retailers restate prior-period comparable sales when the store base changes?
Generally the comparable base is redefined each period rather than restating history, so the figure published a year ago was calculated on a different set of stores than the one published today. Acquisitions, conversions between franchised and owned locations, and format changes all shift which stores qualify. That is one reason a series of published comps is not a clean time series, and why reading the definition attached to each period matters when a retailer has been reshaping its fleet.
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Disclaimer
This article is for educational and informational purposes only and does not constitute personalized investment, financial, or legal advice. Same-store sales methodology, disclosure practices, and definitions vary by retailer and may change over time. Always verify current methodology from a company's own filings before drawing conclusions. Trading involves risk, including the possible loss of principal.