What it means
A business hires people, buys equipment and uses materials because those inputs help it sell output. Marginal revenue product, or MRP, asks what the next unit of an input contributes to sales, not what all existing units contribute on average.
If another hour of skilled work produces four more items and each extra item adds $20 of revenue, that hour has an MRP of $80 before other costs. The calculation has two parts: marginal product measures the change in physical output from the added input, and marginal revenue measures the extra sales revenue from an additional output unit.
OpenStax's labour-market chapter explains that employers' demand for labour reflects the value of workers' marginal contribution to output. Under perfect competition, a firm's marginal revenue per sale equals the sale price, so MRP may be described as marginal product times price.
With market power or price discounts on extra sales, marginal revenue can be lower than the headline price, and using the price without testing that assumption overstates the input's value. Other inputs also matter: a baker may initially produce much more after one extra assistant joins a well-equipped kitchen.
If assistants keep arriving but oven capacity does not, the next person's marginal output may fall, so MRP can decline as one input becomes abundant relative to the rest, even if the early hires were highly profitable. A simple hiring rule compares the next worker's MRP with the full marginal cost of employing that person.
The cost includes wages, benefits, training and other incremental expenses. If MRP exceeds cost, another hire may add profit; if it falls short, the proposed staffing level deserves another look.
For managers, measurement is the hard part. Use controlled pilots, operational data and realistic demand forecasts rather than assigning each employee a mechanical revenue number.
The same logic extends beyond labour: another machine shift, delivery vehicle or advertising unit has a marginal revenue product if its added output or sales can be estimated.
In practice
Real-world examples.
Example
A workshop adds one technician for a shift and completes five extra repairs. If each extra repair adds 40 of revenue after any quantity discount, the technician's shift has an estimated MRP of 200 before the extra employment cost.
Example
A cafe hires another barista during a rush, but its single coffee machine is already full. The next barista adds only a few sales, so MRP is lower than it was for an earlier hire.
Example
A business cuts the price of extra units to attract buyers. The production gain from another machine is unchanged, but the marginal revenue per unit falls, reducing the machine's MRP.
Formula
Calculation
MRP of input X = marginal physical product of X x marginal revenue per extra output unit. If a worker-hour adds 4 items and the extra sale of each contributes $20 in revenue, MRP = 4 x $20 = $80 per worker-hour. Compare that with the full marginal cost of the hour, not wages alone.
Worked example. Suppose the full marginal cost of that worker-hour is $30 wages plus $6 benefits plus $4 training and supervision, which totals $40.
- MRP minus marginal cost = $80 - $40 = $40, so the extra hour adds about $40 of profit.
- If oven capacity limited the next hour to 2 extra items, MRP would be 2 x $20 = $40, equal to its cost, and a further hire would add nothing.Case study
Seen in the real world.
Fictional example: Ashfield Repairs, a fictional appliance-service company, considered hiring a sixth field technician. Its managers first divided annual revenue by five technicians and concluded that any new hire would quickly pay for themselves. The operations lead instead mapped unfilled appointments, travel time and spare diagnostic equipment. A four-week pilot with a contractor produced seven extra completed jobs per week, each adding revenue after the relevant discounts.
The calculated marginal revenue product exceeded the contractor's full cost in two busy districts but fell below cost in a quiet third district. Ashfield hired a technician for the busy area and changed scheduling rather than hiring everywhere. Three months later an equipment shortage reduced completed jobs, so management updated the estimate and bought another diagnostic kit. The board learned to ask what the next unit of labour adds at the current bottleneck, not what the average worker historically produced.
Watch out
Common mistakes.
- Dividing total revenue by workers and treating that average as the marginal revenue product of the next hire.
- Using the sticker price instead of marginal revenue when selling more output requires discounts.
- Comparing MRP with salary alone while ignoring benefits, training and other incremental employment costs.
Questions
People also ask.
Is MRP the same as marginal product?
No. Marginal product measures extra physical output; marginal revenue product values that extra output using marginal revenue. The first may be four units, while the second is a monetary amount.
When does another hire make financial sense?
In a simplified model, when the expected MRP of the next hire exceeds the full incremental employment cost. Real decisions must also consider law, safety, training and uncertain demand.
Can MRP rise rather than fall?
Yes, when a new skill removes a bottleneck or improves how other inputs work. Diminishing marginal returns are common under fixed capacity but not an iron rule for every staffing decision.
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