The short version
Price a retainer from the hours you will include and your normal rate, discount it for the commitment, and set the overage rate at your full rate. The overage rate is what stops a good arrangement quietly becoming a bad one.
Start from hours, not from a round number
A retainer that begins as a comfortable-sounding monthly figure and works backwards to the hours is a retainer you will resent by month four. Start from the hours the client actually needs and multiply by what you charge.
Twenty hours at $95 is $1,900. That is the starting point, and every adjustment after it should be deliberate rather than accidental. The retainer calculator runs this arithmetic and shows the overage rate alongside it.
Decide what the commitment is worth to you
The discount is the price of something specific: guaranteed income you can plan around. There is no standard figure, so pick it deliberately: at 10%, twenty hours at $95 comes to $1,710 a month.
If the guarantee does not actually make your month more predictable, because the client is one of twenty or because they cancel freely, then it is worth nothing and zero is the right discount. There is no rule that says a retainer must be cheaper.
Set the overage rate at your full rate
This is where most retainers go wrong. The discount was for the hours the client guaranteed. Hours past the cap were never guaranteed, so they are worth your full rate.
Some people set it above their full rate to discourage going over; what it must never be is discounted. Discounting the overage rewards the client for going over, which is exactly backwards, and it is how an arrangement that looked like $85.50 an hour at twenty hours quietly becomes far less at thirty.
Say what happens past the cap, before it happens
The failure mode is always the same. The client uses more than the cap, nobody wants to raise it mid-month, and three months later there is a pile of unbilled hours to argue about.
Writing the overage rate into the agreement removes the conversation entirely. Going over becomes a normal, priced event rather than an awkward one.
Do not let hours roll over
Rollover turns a retainer into a prepaid block of hours and removes the predictability you gave a discount for. It also builds a liability: a client who has banked forty unused hours can call them in during your busiest month.
If you do allow it, cap how many months can accumulate and say so in writing.
Check what you are actually earning
The number that matters is the fee divided by the hours you actually work, overage included. A retainer priced on twenty hours that reliably takes twenty-eight is a discount you did not agree to.
The retainer calculator shows that figure directly, so the arrangement can be repriced at renewal from evidence rather than from a feeling.
Worked example
A marketing consultant includes 20 hours a month at her normal rate of $110. Full price for that many hours would be $2,200. She discounts the commitment by 10%, so the retainer is $1,980. The overage rate stays at $110, her full rate, never the discounted one.
In March the client only needs 16 hours. She still bills the full $1,980. That predictability is what the retainer is for, whether the hours are used or not.
In April the client needs 27 hours. She bills the $1,980 retainer plus 7 hours of overage at $110, an extra $770, for $2,750 that month on one invoice with the two amounts on separate lines.
At renewal she adds up what she actually worked over the last six months: 118 hours against 120 retainer hours available (20 hours × 6 months). Close enough that the 20-hour cap is right. If the real average had come out at 26 hours a month instead, the cap would be wrong, not the client, and the retainer would need repricing before the next term starts.
The retainer calculator runs this same arithmetic for your own hours and rate: the discounted fee, the overage rate and the effective hourly rate once overage is included.
Mistakes that turn a good retainer bad
- Picking the fee first. A round number chosen before the hours makes the hours whatever they need to be to justify it, which is backwards.
- Discounting the overage rate. That rewards the client for going over the cap, which is the opposite of what the discount was paying for.
- Leaving the cap unspoken. If the overage rate is not written into the agreement before the client goes over, the first time it happens becomes a negotiation instead of a normal billing event.
- Letting hours roll over with no limit. Uncapped rollover turns the retainer into a prepaid block of hours that can all get called in during your busiest month.
- Never checking the effective rate. A retainer that quietly settles into more hours than it was priced for is a discount you never agreed to, and it only shows up if you check.
Questions people ask
How many hours should a retainer include?
The hours the client actually needs in a normal month, not a round number you worked backwards from. Pricing the hours first and the fee second is what keeps it honest.
How much discount should a retainer get?
There is no standard figure, and zero is defensible. The discount buys predictable income, so size it to how much the commitment is worth to you. If the client's commitment does not actually make your month more predictable, it is not buying anything.
What should the overage rate be?
Your full undiscounted rate. The discount applied to guaranteed hours; hours past the cap were never guaranteed.
Should unused hours roll over?
Usually not. Rollover removes the predictability you discounted for and builds a liability you may have to honor in your busiest month. If you allow it, cap it.
How do I invoice a retainer?
One line for the retainer naming the hours included, and a separate line for any overage showing the hours and the rate. Keeping them separate makes the next renewal conversation straightforward. Most retainers are invoiced at the start of the month, and recurring invoices send the same one each month.
When should I reprice a retainer?
At renewal, using what you actually earned per hour over the term rather than what the fee looked like. If the effective rate has drifted well below your normal rate, the cap is wrong, not the client.
What this is. A guide and template written by Fatima Khan. It is not legal advice. Deposit, cancellation and late fee rules differ by state, so have any wording you rely on checked for your state before it goes on a real document.
Last reviewed by InvoiceTools, Houston, Texas, on 28 September 2026.