A capped retainer and a straight hourly rate can describe the exact same work and still leave very different amounts of money on the table, depending on how many hours the client actually uses. This calculator takes your monthly retainer, the hours it caps out at, and the rate you'd charge for the same work billed hourly, then shows you the effective hourly rate you're really earning under the retainer, the break-even point where the two pricing models pay identically, and the exact monthly dollar gap between them.
How it works
The calculator assumes the worst case for you as the provider: that the client uses every hour in the cap, every month. From your monthly retainer and capped hours, it computes the retainer effective rate — the retainer divided by the capped hours — which is the real per-hour rate you're earning if the cap gets fully used.
It then compares that against your standalone hourly rate two ways. First, break-even hours: the number of hours at your hourly rate that would cost the client exactly the retainer amount. Below that many hours, the retainer pays you more per hour than billing hourly would; above it, hourly billing wins. Second, the monthly difference: the retainer amount minus what the capped hours would cost at your hourly rate. A negative number means the retainer is paying you less than hourly billing would for the same hours; a positive number means the retainer is paying you more.
Worked example
Say you quote a client a $4,000/month retainer capped at 40 hours, and your standalone hourly rate for the same work is $120/hour.
- Retainer effective rate: $4,000 ÷ 40 = $100/hour
- Break-even hours: $4,000 ÷ $120 = 33.33 hours
- Hourly equivalent for 40 hours: 40 × $120 = $4,800
- Monthly difference: $4,000 − $4,800 = −$800
The retainer effective rate of $100/hour sits below your $120 standalone rate, and the negative $800 difference confirms it: if this client consistently uses the full 40-hour cap, you'd earn $800 more per month billing the same work hourly. The break-even hours of 33.33 tells you exactly where that flips — if the client's actual usage stayed under roughly 33 hours a month, the $4,000 retainer would out-earn hourly billing for those same hours.
How to interpret your result
Watch the monthly difference, not just the effective rate in isolation. A retainer effective rate below your hourly rate isn't automatically a bad deal — it only costs you money if the client is actually using hours up near the cap. If a client is capped at 40 hours but historically uses 25, your real effective rate on the hours you deliver is well above what this calculator shows, because it assumes full usage.
The break-even hours figure is the practical trigger for renegotiating. If a client's monthly usage creeps consistently above that number, the retainer has stopped reflecting the value of the work and it's time to either raise the retainer, lower the cap, or move the client to hourly billing. Conversely, if usage regularly sits well below break-even, the retainer is doing its job: paying you a premium for a chunk of your calendar the client isn't fully using, in exchange for the guaranteed income and the fact that they can't walk away mid-month the way an hourly client can. Neither pricing model is universally better — this calculator just makes the trade-off visible in dollars instead of leaving it as a hunch.
Methodology & sources
The formulas are retainerEffectiveRate = monthlyRetainer / cappedHours, breakEvenHours = monthlyRetainer / hourlyRate, and monthlyDifference = monthlyRetainer − (cappedHours × hourlyRate) — all computed from the unrounded inputs before rounding is applied to the displayed figures, so the results stay internally consistent with each other.
Retainer and hourly billing are two of the standard pricing models freelancers choose between; the Freelancers Union's piece on why pricing is so hard covers why leaning on an hourly rate alone tends to cap your income, and where a retainer fee fits in as an alternative. And because a retainer is still gross business revenue, self-employment tax — a flat 15.3% on net earnings, per the IRS — still comes out of it before it becomes take-home pay, same as it would under hourly billing.