Fundamentals
Why sales per labour hour swings — and what your data can tell you
Sales per labour hour (SPLH) is one of the cleanest measures of how efficiently a restaurant is trading: take net sales for a period and divide by the labour hours rostered to produce them. A higher number means each paid hour generated more revenue. But a single SPLH figure hides why it landed where it did — and "why" is the part you can act on.
Almost every swing in SPLH traces back to one of four levers.
1. Covers — how many guests you served
The most obvious driver. If covers fall but the roster stays the same, SPLH drops mechanically. The trap is that rosters are usually set a week ahead, against a forecast — so a quiet Tuesday with a Saturday-sized kitchen team will always look inefficient. The question worth asking isn't "was SPLH low?" but "was it low because covers dropped while labour held flat?"
2. Average spend per cover
Two services can have identical covers and very different SPLH if guests spent differently. This is where menu mix lives: a table that adds Sides and Cold Beverages lifts the check without adding labour. We routinely see attach rate — items per cover in a family group — explain more of the SPLH gap than headcount does.
3. Labour hours — and where they sit
Total hours matter, but timing matters more. A Chef shift that overlaps a dead 14:00–16:00 window costs the same as one over a rush, but earns far less. SPLH measured by service round, rather than by day, surfaces these overlaps — the half-shifts that quietly drag the daily average down.
4. Wage rate mix
The same hours at a different blend of positions changes the cost base. A round leaning on senior Service and Chef rates is more expensive per hour than one covered by Prep and Salad. When SPLH dips without covers or spend moving, the wage mix is often the culprit.
Knowing which lever moved
The hard part isn't the formula — it's attribution. When SPLH drops, was it covers, spend, timing, or rate mix? Answering that from a spreadsheet means pivoting the same data four different ways, by hand, every time you ask.
The number tells you something changed. Only the relationships tell you what.
That's the whole point of asking your data directly. Instead of building a pivot, you ask "why was SPLH lower last Tuesday than Saturday?" and get the breakdown across all four levers at once — with the figures behind it. Here's why a graph makes that natural →