A retainer is not profitable merely because the payment repeats. The relevant question is what delivery commitment that payment buys. This example prices a defined monthly allowance and tests the effect of extra support time.
Define what the monthly fee includes
Assume 20 delivery hours, four support hours and two account-management hours. That is 26 hours in total. Specify what happens to unused hours, which response times are promised and which requests require a separate estimate. These terms change capacity and cost even if the monthly invoice stays the same.
The fictional cost assumptions below exclude taxes, sales commission and financing.
| Included cost | Calculation | Amount |
|---|---|---|
| Delivery, support and account time | 26 × 30 | 780 |
| Client-specific licences | Monthly cost | 120 |
| Shared overhead allocation | 26 × 10 | 260 |
| Total | 1,160 |
The labour rate excludes the licence charge and shared overhead. A licence already included in the shared cost pool must not also be charged here.
Calculate the retainer price
At a hypothetical 20% margin after those costs:
Monthly price = 1,160 ÷ 0.80 = 1,450
The planned retained amount is 290. Use the agency quote calculator with combined direct costs of 900, overhead 260, margin 20% and zero commission. This adapts its one-unit quote to one month of the explicitly defined service.
Test support creep
If support takes six additional hours, labour rises by 180. If overhead follows actual hours, add another 60. Cost becomes 1,400 and the original 1,450 fee leaves 50, or a 3.45% margin.
At the original cost convention, a 20% target would require a fee of 1,750. Before changing a price, determine whether the extra work is recurring, an estimating error or outside the agreed scope.
Separate shared licences from dedicated costs
If an additional dedicated tool costs 200 each month, the cost base becomes 1,360 before the support overrun. A 20% planning margin then implies 1,700. Do not spread that cost over clients who do not use it unless that is your explicit allocation policy.
Check capacity and payment timing
Four identical retainers commit 104 hours before extra requests. Compare that with practical delivery capacity after internal work, leave and sales activity, not with all paid hours. See capacity planning.
A monthly fee invoiced at the start of a month is not necessarily collected at the start. Put the expected receipt date into the cash forecast, and test a late payment from a large client separately.
This example does not estimate customer lifetime value or renewal probability. Use observed retention data for those questions; recurring billing alone does not establish either.
About the examples and sources
The figures are hypothetical teaching examples created for AskToBot, not surveyed prices or recommended industry margins. The linked references explain the underlying concepts; they do not supply or endorse these example figures. The arithmetic is checked against the stated assumptions. This is AI-assisted educational content and has not been independently reviewed by an accountant. Read how we check calculations.
