Retainer billing with rollover and overage
Sumhour is retainer management software for agencies. You set the included hours, the fee and the period (a month, a quarter or a year). Unused hours expire or carry over, up to a cap if you want one, and retainer invoicing covers the fee and any hours over the retainer at your overage rate.
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Retainer periods
| Period | Used / included | Overage | Retainer invoice |
|---|---|---|---|
| Nov 202612:00 carried over | 9:30 / 72:00 | 0:00 | Not invoiced |
| Oct 2026 | 48:00 / 60:00 | 0:00 | INV-1039 |
| Sep 20268:00 carried over | 74:30 / 68:00 | 6:30 | INV-1030Overage INV-1033 |
Harbor Health in September: 6:30 over the retainer
Harbor Health buys 60 hours a month for USD 6,000. Unused hours carry over up to 12, and hours over the retainer bill at 140.00. August left 8 hours unused.
The fee and the overage go out as separate invoices, so the client sees exactly what the extra hours cost.
| Included this month60:00 + 8:00 carried over | 68:00 |
|---|---|
| Worked | 74:30 |
| Over the retainer74:30 − 68:00 | 6:30 |
| Retainer feeINV-1030 | 6,000.00 |
| Overage6:30 × 140.00, INV-1033 | 910.00 |
| Billed for September | 6,910.00 |
Demo workspace: Birch & Row Studio, USD
Retainers in Sumhour, step by step
- 01
Set up the retainer
Create the project as Retainer and enter “Included hours per period”, the “Retainer fee” and a “Period”: month, quarter or year.
- 02
Choose the rules
Unused hours expire, carry over, or carry over up to a cap. Hours over the retainer are billed at an overage rate, absorbed, or left for you to decide later.
- 03
Track as usual
People log time to the project like any other. The project page lists each retainer period with its hours.
- 04
Invoice each period
“Invoice fee” drafts the period’s fee. “Invoice overage” drafts the extra hours at the overage rate and locks that period’s entries.
Set the hours, the fee and the period
A retainer is a project type, next to hourly, fixed fee and non-billable. It asks for the hours the client buys each period, the fee they pay for them and whether the period is a month, a quarter or a year.
Two more settings decide what happens to unused hours and to extra hours. The rate for the time itself comes from one project rate, task rates or person rates, as on an hourly project.
Retainer settings in the guideNew project · Billing
Decide what happens to unused hours
"Expire at period end" starts every period fresh. "Carry over" adds the hours left to the next period. "Carry over up to a cap" does the same until it reaches the "Rollover cap (hours)" you set.
In October, Harbor Health used 48:00 of its 60:00. The 12:00 left carried into November, which now holds 72:00.
- Each period shows used hours against included hours
- Included hours count anything rolled over
Used against included
Retainer invoicing for hours over the retainer
"Bill at the overage rate" charges every hour past the included hours at the "Overage rate" you set. "Absorb (do not bill)" keeps the extra time off the invoice. "Alert me, decide later" leaves the call to you.
When a period goes over, "Invoice overage" drafts the extra hours at the overage rate (or the project’s hourly rate) and locks that period’s entries so they are not billed twice.
How retainer invoices workEvery retainer on one table at month end
The month-end page has a "Retainers this period" table. Each retainer shows its current period, used against included hours, any overage and its retainer invoice. A period with no fee invoice yet reads "Not invoiced".
"Invoice retainer" drafts the fee from there, and "Invoice overage" appears when the period went over. Accountants can use both. Retainer time stays out of "Draft all invoices", because these invoices bill it.
More on month-end closeRetainers this period
| Retainer | Period | Used / included | Retainer invoice |
|---|---|---|---|
| Monthly design supportHarbor Health | Nov 2026 | 9:30 / 72:00 | Not invoiced |
| Quarterly SEO reviewHarbor Health | Q4 2026 | 14:00 / 30:00 | INV-1038 |
Retainers: limits to know about
- “Draft all invoices” at month end leaves retainers out. Each retainer’s fee is drafted on its own, with “Invoice fee” on the project or “Invoice retainer” at month end.
- On the project page, only an owner or admin can draft retainer invoices. Accountants draft them from month end.
- Month end can write off hours on a retainer row, but it cannot write down the amount.
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Retainers: Sumhour and other tools
Checked against each tool’s own pricing and help pages on November 5, 2026; the sources are under the table. Plans change, so check before you rely on a line.
| Feature | Sumhour | Productive | Teamwork.com | FreshBooks | Clockify |
|---|---|---|---|---|---|
| Unused retainer hours roll into the next period | Every plan | Rollover on Ultimate | Rollover on Optimize | No: unused time does not carry forward | No: budgets reset |
| Hours over the retainer billed as overage | Every plan | Not documented | Not documented | Overage on Plus ($43 a month) | No: budgets reset |
Sources: Productive retainer rollover; Teamwork.com retainer budgets; Teamwork.com plans; FreshBooks retainers; Clockify project budgets.
Full comparison: Sumhour vs Harvest.
Retainers: common questions
How does retainer hours rollover work?
On the retainer project, set “Unused hours” to “Carry over” and the hours left at the end of a period are added to the next one. “Carry over up to a cap” stops at the “Rollover cap (hours)” you enter, and “Expire at period end” drops them. The next period’s included hours then show the retainer’s hours plus anything rolled over.
Retainer setup in the guideHow do I bill overage hours on a retainer?
Set “Hours over the retainer” to “Bill at the overage rate” and enter an “Overage rate” per hour. When a period goes over, “Invoice overage” drafts the extra hours at that rate (or the project’s hourly rate) and locks that period’s entries.
Can a retainer be billed quarterly or yearly?
Yes. The retainer’s “Period” can be a month, a quarter or a year. The included hours, the fee, the rollover and the overage all apply to that period.
How do I see retainer usage for the month?
Month end has a “Retainers this period” table. It lists each retainer with its current period, used against included hours, any overage and its retainer invoice, or “Not invoiced” when the fee has not been drafted yet.
Is retainer billing included in every Sumhour plan?
Yes. A one-person workspace on Solo gets the same retainers as a team on Scale: rollover, a rollover cap and overage billing. There is nothing extra to buy.
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