Virtual assistant work has an invoicing problem that a plumber never faces: the client can't see what you did. A plumber leaves behind a working faucet. You leave behind a calm inbox, a calendar that didn't double-book, and forty small tasks the client never saw because you handled them first. Then you send an invoice for 17.5 hours and the client thinks, "Really? For email?"
That gap between invisible work and a visible bill makes VA invoicing an evidence business. This guide covers the four ways VAs price work, what the time log has to show, how to display prepaid hours draining down on the invoice, and how to run billing across six clients at once.
The quick version
- Bill hourly work with a time-tracking summary attached. The invoice shows total hours by category; the attached log shows date, task, and duration for every entry.
- Prepaid hour packages are the VA sweet spot. Invoice the package before the month starts, then show drawdown on the invoice: hours purchased, used, and rolled over per your stated policy.
- A retainer guarantees your availability; a package just sells a block of hours. Price the retainer higher for that guarantee, and let unused retainer hours lapse.
- Use flat task fees for defined deliverables like an inbox cleanup or a multi-leg travel booking: fixed scope, fixed price, no timer.
- Invoice every client the same day each month, with a numbering scheme that includes a client code, so nothing slips.
- Small invoices should be due on receipt, not net 30. Waiting a month to collect a few hundred dollars breaks a solo VA's cash flow.
- Start from a virtual assistant invoice template so the package, drawdown, and time-log structure is already in place.
Hourly billing lives or dies on the time log
Straight hourly is where most VAs start. The general mechanics (increments, rounding, time-based line items) are covered in the hourly billing guide; here is what's specific to VA work.
The invoice line should summarize by category, not list every task. Something like "Administrative support, June 1–30: 17.5 hrs @ $35/hr" as the line item, with the detail living in an attached time-tracking summary. That attachment is your dispute insurance. A good VA time log shows the date, the task in plain client language ("Booked SFO–AUS flights + hotel for July conference," not "travel admin"), and the duration. Most time trackers export exactly this; attach it as a second page of the PDF and reference it on the invoice ("Detailed time log attached: 42 entries").
Two VA-specific policies belong in your terms because they cause most hour disputes:
- Minimum billing increment. VA work arrives as five-minute fragments: a quick Slack ask, a fast reschedule, one email draft. Most VAs bill in 15-minute minimum increments as common industry practice, so a 4-minute task bills as 0.25 hours; state the increment in your terms.
- Pre-approval threshold. "Hours beyond 25/month require written approval" protects both sides from a surprise invoice after a chaotic month.
Prepaid hour packages: show the drawdown on the invoice
Packages are the structure most experienced VAs converge on: the client buys a block of hours (10, 20, 40) at the start of the month, usually at a small per-hour discount versus your straight rate. You get paid before the work, which flips the usual freelancer cash-flow problem.
The invoicing mechanics that make packages work:
- Invoice in advance. The package invoice goes out before the period it covers, due before the hours start. "Prepaid support package: 20 hours, July 2026" invoiced in late June.
- Show the drawdown every month. Each invoice reports the previous package's usage as an informational line: hours purchased, hours used, hours remaining. Clients who can watch the meter don't ask where their money went.
- State the rollover policy on the invoice itself, every time. Common industry practice runs from "unused hours expire at month end" to "up to 5 hours roll over one month." Print yours in the notes; expired-hours disputes almost always trace back to a policy the client never saw.
- Set an overflow rate. When the client burns through the package mid-month, extra hours bill at your standard (non-discounted) rate on the next invoice, with pre-approval noted.
Package versus retainer: a true retainer means the client is buying guaranteed availability. You hold capacity whether they use it or not, unused time lapses, and the price reflects the reservation. A package is just a prepaid block of hours with no availability promise, which is why rollover is negotiable there and rarely is on a retainer. The mechanics of structuring and invoicing retainers are covered in the retainer billing guide.
Flat task fees for defined deliverables
Some VA work is a project, not a stream of hours, and billing it hourly punishes you for being fast. Anything with a defined start and finish can carry a flat fee: an inbox cleanup with a filter and label system, migrating a client to a new project-management tool, building a standard-operating-procedure document, researching and booking a multi-city trip.
Flat-fee line items need a scope sentence right in the description, because "inbox setup" means different things to different clients. "Inbox cleanup and organization: archive backlog, build 12 filters/labels, write 5 canned responses" is a line item that defends itself. If the client adds scope mid-task, that's a new line, not a bigger number on the old one.
Flat fees mix cleanly with packages on the same invoice, which is exactly what the example below shows.
What a monthly VA invoice actually looks like
Here is a realistic month for a VA billing a 20-hour package plus a flat-fee project and pre-approved overflow (all prices are examples, not rate guidance):
| Description | Qty | Rate | Amount |
|---|---|---|---|
| Prepaid support package: 20 hours (July 2026) | 1 | $600.00 | $600.00 |
| June package drawdown: 20 purchased, 17.5 used, 2.5 rolled to July (max 5) | - | - | $0.00 |
| Inbox cleanup: backlog archive, 12 filters, 5 canned responses (flat fee) | 1 | $150.00 | $150.00 |
| Overflow hours beyond June package (approved 6/24) | 3.25 hrs | $35.00/hr | $113.75 |
| Total due on receipt | $863.75 |
Notes section: "June time log attached (42 entries). Unused package hours roll over one month, max 5. Time billed in 15-minute increments. Overflow beyond package bills at $35/hr with prior approval."
Two things to notice. The drawdown line is informational, billing $0.00, but it does more client-relations work than anything else on the page. And the period covered is explicit on every time-based line, because a VA invoice that just says "services" invites a line-by-line interrogation. The full checklist of required invoice fields is in what to include on an invoice.
Six clients, one billing day
The hard part of VA billing isn't any single invoice; it's that you have many small ones. The fix is a same-day rhythm: every client gets invoiced on the same date, usually the 1st (packages in advance, prior month's overflow in arrears) or the last business day. Batching turns billing into one 90-minute block a month instead of a background anxiety, and it means a missed invoice is obvious because the stack has a hole in it.
Give the stack a numbering scheme with a client code, like ACME-2026-07; the invoice numbering guide covers schemes that scale, and the recurring invoicing guide covers systematizing the repeat package invoices.
Payment terms should match the invoice size. Corporate-style net 30 makes no sense on a few hundred dollars of prepaid hours; due on receipt is the norm, and packages simply don't start until payment lands. Offering an online payment option is worth it at VA invoice sizes: invoices with online payment options get paid up to twice as fast (Xero, 2024). Expect a W-9 request once a US business client's payments to you cross the IRS reporting threshold for the year; the W-9 and 1099 guide explains the paperwork.
Invoicing international clients
VA work is one of the most borderless trades there is, and many US VAs carry at least one overseas client. The additions are small but non-optional: state the currency explicitly on every line ("USD" not just "$") and agree on who absorbs conversion and transfer fees before the first invoice. Sales tax on services varies by state, and cross-border tax treatment adds another layer, so verify your own situation. The full mechanics, from currency clauses to payment rails, are in the international invoicing guide.
If you're billing in euros or pounds, Invoity's editor handles multi-currency directly. The virtual assistant invoice template pre-fills the editor with VA-style line items, package and drawdown structure included, and you can adjust it, download the PDF instantly, and send, no signup required to start.
Frequently asked questions
Should I attach my full time log to every VA invoice?
Yes, whenever you bill hourly or bill overflow beyond a package. Keep the invoice line itself summarized by category and let the attached log carry the per-task detail. Clients rarely read every entry, but knowing the entries exist is what stops the "did that really take an hour?" conversation before it starts.
What happens to unused hours in a prepaid package?
Whatever your written policy says, which is exactly why the policy must appear on the invoice itself. Common industry practice ranges from use-it-or-lose-it at month end to a capped one-month rollover, like the "max 5 hours" example above. Never let rollover accumulate indefinitely, or you'll eventually owe a client 40 hours of banked work in a month you don't have capacity for.
How do I bill lots of tiny five-minute tasks?
Set a minimum billing increment, typically 15 minutes, and state it in your terms so a 4-minute ask bills as 0.25 hours. If a client's requests are constant micro-tasks, that's a signal to move them onto a package or retainer, where the drip of small work is exactly what the prepaid hours are for.
Should I invoice a package before or after the month?
Before. Prepaid is the entire point: the invoice goes out in the last week of the prior month, payment lands before the hours begin, and work pauses if it doesn't. Only overflow hours and flat-fee projects completed during the month bill in arrears on the next invoice.