Contract Extension Value

Why this comes up

When a contract or temp assignment nears its end date, extending it looks like the safe default: no new sourcing, no gap in billing, no risk of the client going elsewhere for the replacement. But "safe" isn't the same as "worth the most." An assignment that's easy to replace with a similar or better-margin one is sometimes worth letting end, and an assignment that would leave a real coverage gap if it lapsed is worth extending even at a below-average rate. This engine puts a number on that tradeoff instead of defaulting to whichever option feels lower-effort.

How we calculated this

Extension Contribution = Extension Duration x Contribution per Time Unit - Incremental Extension Cost
Expected Replacement Value = P(replace) x (Extension Duration x Contribution per Time Unit - Replacement Sourcing Cost) - (1 - P(replace)) x Gap Risk Cost
Expected Value of Extending = Extension Contribution - Expected Replacement Value

Worked example, using the calculator's own defaults: a 26-week extension at $600/week contribution, no incremental extension cost, a 40% probability of successfully replacing the assignment elsewhere, a $1,500 replacement sourcing cost, and a $2,000 gap risk cost.

Extension contribution = 26 x 600 - 0 = $15,600
Expected replacement value = 0.40 x (26 x 600 - 1,500) - 0.60 x 2,000
                            = 0.40 x 14,100 - 1,200 = 5,640 - 1,200 = $4,440
Expected value of extending = 15,600 - 4,440 = $11,160

Extending wins by a wide margin here, $11,160 in expected value over replacing, mostly because the 40% replacement probability means there's a 60% chance of paying the full $2,000 gap risk cost for nothing.

What this means

• Extension contribution alone (the guaranteed number) is the floor; the expected-value comparison against replacing is only as good as your probability-of-replacing estimate, and it can push the decision either direction depending on that number.
• A low probability of replacing the assignment makes extending look better even at a modest contribution rate, because the alternative carries real gap risk with only a small chance of avoiding it.
• A high probability of replacing, paired with a low gap risk cost, can flip the decision toward letting the contract end, especially if the replacement assignment would carry a meaningfully higher contribution rate.
• Incremental extension cost (a rate concession, added scope, anything the client wants in exchange for the extension) comes straight out of the contribution figure before any comparison happens; don't leave it at zero if the extension isn't a straight renewal.

Limitations

The replacement comparison is optional and only as reliable as your own probability-of- replacing estimate; leave it out if you have no basis for that number and just use the extension contribution on its own. It also treats contribution per time unit as flat for the full extension period, it doesn't model a rate that steps up or down partway through, and it doesn't weigh relationship value with the client beyond the dollars in the comparison.

Common mistakes

• Extending automatically because it's the path of least effort, without ever running the replacement comparison to check whether it's actually the better dollar outcome.
• Using a gut-feel probability of replacing instead of your own historical fill rate for similar assignments.
• Forgetting to include incremental extension cost when the client is asking for a rate concession as part of the renewal.

Frequently asked questions

What if I have no idea what my probability of replacing the assignment is?

Leave the replacement comparison off and use the extension contribution figure on its own. A rough guess plugged into an expected-value formula is worse than no comparison at all.

Does gap risk cost include lost billings during the gap?

It should, along with any client-relationship cost of a coverage gap, since those don't show up anywhere else in this calculation.

Should I run this before or after negotiating the extension terms?

Both. Run it before to know your floor, and again with the final negotiated contribution rate and incremental cost to confirm the deal you land on still clears it.

Next decision

• Roll this contract into your full service-model comparison
• Check the full client account economics behind this assignment

Learn more

Temp, Temp-to-Hire, and Direct-Hire Economics — how contract revenue recurs differently from a one-time placement fee, and why that changes how you should value an extension.