Part-Time vs. Full-Time Virtual Assistant: How Many Hours Do You Actually Need?

She hired a part-time VA at 15 hours per week in January. By February, the VA had handled her inbox, travel research, and weekly reporting so well that she kept finding more to hand off, supplier follow-ups, client communication, social media scheduling. By early March she had a clear 25 hours of ongoing work to delegate. She called her VA to expand the arrangement. The VA was sorry, she had already filled her remaining capacity with a second client two weeks prior.

Restarting the search, rerunning interviews, and rebooting onboarding cost that executive a full month and roughly $3,200 in her own time. The additional $800 per month to hire full-time from the beginning would have cost her $1,600 over those two months. The math is not complicated, but you only see it clearly in retrospect.

This guide gives you the calculation to see it clearly in advance.

Why “I Know How Many Hours I Need” Is Almost Always Wrong

Most executives underestimate their delegation volume for a consistent reason: they calculate based on what they currently delegate, not what they could delegate. At the moment of hiring, they have never had a VA, so their reference point is tasks they have already figured out how to handle themselves, the emails they skim in 90 seconds, the scheduling they do in the flow of their day, the data pulls they have internalized as “quick” because they have done them 200 times.

None of that work feels like work when it is already your habit. But add it up over a week, and it is 15 to 25 hours of output that another person could produce for you, if you have the infrastructure to hand it over.

There is a second systematic error: scope expansion. Every successful delegation tends to surface more delegation opportunities. The executive who hands off email management realizes her VA could also draft client follow-ups. The VA who handles travel research could own the vendor contract renewals. The person managing weekly reporting could take over the quarterly data compilation. The first 60 days of a VA relationship reliably produce a delegation list that is 30–50 percent longer than the one you started with.

If your VA is already at full capacity with another client, that expansion has nowhere to go.

The Hours Calculation Formula and the 1.25 Overhead Factor

Before you decide between part-time and full-time, you need a reliable estimate of your actual delegation volume. The Hours Calculation Formula produces that estimate in three steps.

Step 1: List your Quick Win tasks

Quick Wins are Tier 1 and Tier 2 tasks (using the 4-Tier Delegation Framework) that you can hand off in the first 30 days: inbox management, calendar coordination, data entry, travel booking, weekly reporting, customer support responses, social media scheduling. For each task, estimate the weekly hours it currently consumes.

Example Quick Win audit:

• Inbox management and email drafting: 6 hours/week
• Calendar scheduling and meeting coordination: 3 hours/week
• Weekly reporting and data compilation: 2 hours/week
• Travel research and booking: 1 hour/week (averaged)
• Customer follow-up emails: 2 hours/week
• Quick Win subtotal: 14 hours/week

Step 2: List your Major Project tasks

Major Projects are Tier 2 and Tier 3 tasks that require more onboarding time but represent significant ongoing delegation volume: content creation, bookkeeping, marketing support, operations management, research synthesis. Estimate weekly hours on a steady-state basis (not the one-time setup cost).

Example Major Project audit:

• Blog and social content drafting: 4 hours/week
• Bookkeeping and expense reconciliation: 3 hours/week
• Vendor and supplier coordination: 2 hours/week
• Major Project subtotal: 9 hours/week

Step 3: Apply the 1.25 Overhead Multiplier

Add your Quick Win and Major Project hours, then multiply by 1.25. This overhead factor accounts for four consistent sources of additional time that are invisible in task estimates: daily check-ins and communication, your VA’s questions during ramp-up, workload spikes and variable weeks, and the natural friction of any new working relationship.

Using the example above:

• Total task hours: 14 + 9 = 23 hours/week
• With 1.25 overhead: 23 × 1.25 = 28.75 hours/week
• Recommended contract: 30 hours/week (round up to the nearest natural contract increment)

This executive’s initial instinct might have been “I have about 20 hours of work to delegate, so 20 hours.” The formula reveals that 20 hours of tasks actually warrants 25 hours of contracted time, and accounting for the scope expansion that typically occurs in month two, a 30-hour arrangement is more defensible than a 20-hour one.

Part-Time vs. Half-Time vs. Full-Time: A Complete Comparison

Armed with your hours calculation, use this comparison to select the right arrangement.

Part-Time: 10–20 hours/week ($800–$1,600/month)

Part-time works well in three specific scenarios: you are testing the VA model for the first time and want to limit risk during the learning curve; your delegation scope is genuinely narrow and task volume will not grow significantly; or your budget is constrained and you are optimizing for a lower monthly commitment.

The structural limitation of part-time is availability. A part-time VA, particularly one hired through a platform rather than an agency, almost certainly has one or more other clients filling their remaining hours. Your 15-hour arrangement gives you 15 hours, and when those hours are consumed, you wait until the next week or negotiate additional capacity that may or may not exist.

Part-time also typically means scheduled availability windows rather than on-demand responsiveness. For roles where timing matters, customer inquiries, same-day turnarounds, real-time coordination, this can create friction that full-time eliminates.

Half-Time: 25–30 hours/week ($1,600–$2,400/month)

Half-time is often the right landing point for executives whose hours calculation produces a result in the 20–26 hour range. You get more dedicated attention than part-time without the full-time commitment, and many excellent VAs prefer this structure because it gives them stability with one client while maintaining some portfolio diversity.

The risk at half-time is the same as part-time, just smaller: 10 to 15 hours of your VA’s week belong to someone else. When you are ready to expand the relationship, as most executives are by month three, you are negotiating for hours that may already be spoken for.

Full-Time: 35–40 hours/week ($2,400–$4,000/month)

Full-time creates a categorically different relationship. Your VA is dedicated exclusively to your business, or should be, and should be explicitly contracted as such. This exclusivity produces three advantages that part-time and half-time cannot replicate.

First, responsiveness improves dramatically. A full-time VA who works in your business context all day, every day, develops context that a part-time VA cannot accumulate at the same rate. They start anticipating your preferences rather than asking. They flag problems before you notice them. They develop institutional knowledge that makes each week more efficient than the last.

Second, trust compounds faster. The 4-Tier Delegation Framework’s progression from Tier 1 to Tier 2 to Tier 3 happens in months, not years, when your VA is fully immersed in your business. The executive who wants a chief of staff in 18 months needs to start with full-time engagement now.

Third, scope expansion is unconstrained. When you find new work to delegate, and you will, there is capacity to absorb it. The relationship grows with your needs.

The data on VA outcomes consistently shows that most high-performing, long-tenure VA relationships run 35–40 hours per week. Part-time relationships are where executives test the model. Full-time is where they build it.

Common Scenarios: What Executives at Different Stages Typically Need

Solo founder, $500K–$2M revenue: Hours calculation typically produces 20–28 hours. Start at 25 hours (half-time) with an explicit plan to expand to full-time by month three. Budget: $1,600–$2,400/month.

Executive at a growing company, 5–15 employees: Hours calculation typically produces 28–35 hours across email, scheduling, operations support, and project coordination. Start full-time. Budget: $2,400–$3,200/month for a Tier 2–3 generalist.

Executive with an existing EA or admin: If you already have in-office support and are adding a VA for specific tasks (content, bookkeeping, research), part-time at 15–20 hours may be appropriate. Budget: $800–$1,400/month.

Executive building a VA team: If you are scaling beyond one VA, adding a specialist to complement a generalist, each role should be independently calculated. Do not assume a new specialist needs full-time; run the formula separately.

The Growth Consideration: Hiring for Today vs. Building for the Next 12 Months

The hours calculation above produces a static estimate: what your delegation volume looks like today. But VA relationships are not static, and your hiring decision should account for trajectory.

Ask: What does my task list look like in six months if this role succeeds? If the answer is significantly more than today, because the VA taking over your inbox frees you to take on more client work, which generates more communication volume, then your six-month hours requirement may be 30–40 percent higher than your current calculation suggests.

Hiring at the six-month projected volume rather than the current volume is not wasteful, it is the decision that avoids restarting a search and re-running an onboarding. The cost of the extra hours for months one through three is almost always lower than the cost of rehiring.

There is one counterargument worth taking seriously: if you are genuinely uncertain whether the VA model will work for your business, starting part-time to test and validate before committing is rational risk management. The key is deciding in advance what success looks like at the 60-day mark and being prepared to expand immediately when you hit it, not waiting until your VA has filled their remaining capacity with another client.

Your Next Step

Run the Hours Calculation Formula before you post your job description. Take 20 minutes, list your Quick Win tasks and Major Project tasks, estimate weekly hours for each, add them together, and multiply by 1.25. If the result is under 15 hours, start part-time with a clear 90-day review date. If the result is 16–25 hours, start at half-time. If the result is 26 hours or more, start full-time.

Then add one more step: project your delegation volume at six months, assuming the first 60 days go well. If that projection adds 20 percent or more to your current estimate, hire at the higher capacity now.

The VA Hiring Circle’s hours calculator at vahiringcircle.com walks you through this exercise with a structured task audit and generates a recommended weekly hours target before you commit to a contract structure. Use it, the input it requires takes 20 minutes, and the output prevents the month-long, $3,000 mistake that comes from learning this lesson the hard way.