Every billable hour you sell carries a 28.6% admin tax. Here is the line-item bill, and the half of it that is honestly reducible.

It means that for every billable hour you sell, some number of unbillable admin minutes are spent making that hour billable: writing the invoice, updating the CRM after the call, drafting the follow-up, sending the weekly status, chasing the late payment. Express that as a percentage of total working time and you get a tax rate. On the typical solo consultant working pattern (25 billable hours plus 10 admin hours per week), the rate is 10 / 35 = 28.6%. At a $150 blended rate that is roughly $1,500 a week of unbillable time, or about $69,000 a year, charged at consultant rates because it is your time.

The 10 hours of admin per week comes from an independent consultant survey reported by Time Etc, which puts the average week at 52 hours total with about 10 hours on admin. The 25 billable hours per week is the working assumption used in the consulting revenue math at /Users/matthewdi/ai-for-consultants/consulting-business-workflow.md (line 222), and it is consistent with the 65-80% utilization band quoted by Bill4Time, eResource Scheduler, and Saviom for consulting practices. Your own number is whatever your timesheet actually shows; the framework holds at any utilization.

Because the tax framing forces the math you avoid when you call it non-billable time. A tax has a base, a rate, and a bill. Non-billable time has none of those; it just sits in a category in your timesheet. The base is your working hours. The rate is the admin share of those hours. The bill is the dollar value of the time at your blended consultant rate. Naming the bill is what makes it visible. Most consultants underestimate the tax rate by a factor of two because they only count the hours they remember; the post-call 20-minute CRM updates and the inbox triage between deep-work blocks rarely make it into the timesheet.

Stacks on top, and that is the part most consultants do not run the numbers on. Of the $172,500 gross at 25 billable hours times $150 times 46 weeks (consulting-business-workflow.md, line 230), the line items go: 28.6% of your time funded the back office (an embedded tax of ~$49,000 in opportunity cost on the same hourly scale), then on the cash that did clear, 15.3% self-employment tax on net earnings, then federal income tax at the relevant marginal bracket (22-32% for most solo practices), then state income tax if you owe it. The IRS tax cadence is real on the calendar too: Apr 15, Jun 15, Sep 15, Jan 15. The admin tax pays the prep work that makes those four payments happen on time.

Reducible: invoicing and dunning, post-call CRM updates, weekly status emails, inbox triage on the obvious replies, the mechanical part of bookkeeping (categorization rules), scope-change line items. These are fuzzy-trigger or calendar-trigger chores where the per-instance variation lives in the content of an email, a transcript, or a SOW. Roughly six of the ten weekly hours sit here. Irreducible: the quarterly tax filing decision (talk to your CPA), contract negotiation, the rate-review conversation with a long-tenure client, the sensitive-tone followup after a hard call, and the quarterly pipeline judgment about which dormant clients to chase. About four of the ten hours sit here, and they should stay with you or with a fractional ops person.

Two ways to read it. If you backfill the freed time with billable work: 6 hours/wk at $150/hr * 46 weeks = $41,400/yr in additional gross, less roughly 30-35% combined SE plus federal tax, nets approximately $27,000 to $29,000 take-home. If you do not backfill and just take the time back: you recover one full work-day per week, the admin tax rate drops from 28.6% to about 13.8%, and the effective billable rate on time invested rises from $107/hr to $129/hr. Most consultants do some of both, which is fine; the framework just makes the trade explicit.

On part of it, yes. A VA at $25-40/hr for 20-40 hours a month closes some of the reducible six hours, mostly on calendar-trigger chores (monthly bookkeeping reconciliation, weekly inbox triage on a fixed cadence). Where a VA struggles is response-time loops where the trigger is content rather than a fixed time: the post-call CRM update has to land in the hour after the call, not on the VA's Tuesday morning shift; the dunning email at Net+7 has to go out the day Net+7 trips, not the next day the VA is in their working hours. The honest stack for most solo practices is a part-time VA on the human-judgment loops plus software on the response-time loops, not one or the other.

Run two calendar weeks. In each week, log every block of time you spend on the back office in a single text file. Tag each block with one of the nine line items above (invoicing, post-call CRM, weekly status, inbox triage, bookkeeping, pipeline admin, quarterly tax workflow, contracts, tool maintenance). At the end of the two weeks, sum the hours, divide by total working hours, and multiply by your blended hourly rate. That is your admin tax in time and in dollars. The number that surprises most consultants is not the total; it is the post-call CRM line, which almost always doubles when you actually log it instead of estimating it from memory.

Clone is software that reads your screen and types into your existing apps from plain English instructions. For the six reducible hours (invoicing on milestone signoff, CRM update after a Zoom call, weekly status drafts, follow-up drafts, dunning at Net+7/14/21, scope-change line items), it closes the loop on the event that triggered it, without API plumbing and without a new tool to learn. For the four irreducible hours, it gets out of the way; those stay with you or with a fractional ops person. Solo plan is $49/month, runs locally on your machine, no client data leaves your computer. Free 14-day trial, no credit card required.

Different shape of answer. Replace-the-stack suites (HoneyBook, Dubsado, Bonsai, Ignition) collapse two or three line items (proposals, contracts, invoicing in one flow) into a single suite, but they do it by asking you to migrate your CRM, your client portal, and your invoicing into their product. The trade is real: if your work is one repeatable engagement on one cadence (wedding photographers, fixed-scope brand work), the suite cuts the admin tax cleanly. If your seven loops have seven different clocks, the suite covers two well and leaves the other five running on its default cadence, which usually is not the cadence you actually want. The reducible-vs-irreducible split here is shape-agnostic; it tells you which line items are worth automating regardless of which tool you use.

It is the median for a solo or boutique advisory practice with five to eight active clients on retainer or project. It is lower (~15-20%) for consultants who run one or two large engagements at a time and have a ops person already; it is higher (~35-45%) for consultants in the first year of practice who have not yet templated proposals, contracts, or status reports. The framework holds at any rate; only the calibration changes. Plug your own hours and rate into the formula in the answer above and you have your number.

The per-loop close windows and trigger types are in the companion guide at /t/automate-consulting-back-office. The Friday batched-admin-block diagnostic (which is the failure mode that produces a 28.6% admin tax even when you think you have a system) is at /t/solo-consultant-batched-admin-block. The two-clock model that separates draft cadence from approve cadence (and is the reason the reducible six hours can come off your Friday block) is at /t/batch-consulting-admin-work.