Patient acquisition cost — how to calculate CAC

Work out your cost per patient and ad payback in the patient acquisition cost calculator.

What is patient acquisition cost?

Patient acquisition cost is the amount a clinic spends to win one new paying patient. It includes not just the ad budget but everything that drives acquisition: the agency, the call center, the CRM, sales bonuses.

The basic formula:

CAC = (marketing costs + sales costs) / number of new paying patients

The key word is "paying." Not leads, not calls, not even booked appointments — patients who came in and paid. That's the only way CAC can be compared with revenue.

How is CAC different from CPL and CPA?

Cost per lead (CPL) and patient acquisition cost (CAC) are often confused, and as a result clinics cut good channels and scale bad ones.

Example: channel A brings leads at UAH 150, channel B at UAH 400. On CPL, channel A looks three times better. But if 5% of channel A's leads end up paying versus 25% from channel B, a patient from channel A costs UAH 3,000 and one from channel B costs UAH 1,600. The cheap leads turned out to be expensive patients.

Which costs should you include in CAC?

For CAC to reflect reality, count the full cost of acquisition, not just what the ad account shows.

Include:

• ad budgets: Google Ads, Meta, other platforms;
• agency or marketer fees;
• salaries and bonuses of front-desk staff or the call center, for the share of time spent on new patients;
• tools: CRM, telephony, website, quizzes;
• fees paid to referrers and partners for new patients.

Don't include:

• doctors' pay for treatment;
• consumables and room rent;
• the cost of retaining existing patients (track it separately).

It helps to track two figures: ad CAC (ad spend only — for comparing channels with each other) and fully loaded CAC (all costs — for judging the clinic's overall economics).

How to calculate CAC by channel: a worked example

Below is an example with hypothetical monthly figures for a clinic. All calculations use the formulas above. Amounts are in Ukrainian hryvnia (UAH).

The average ticket in this example is UAH 6,000. ROMI is calculated as:

ROMI = (channel revenue − channel spend) / channel spend × 100%

For Google Ads, for instance: (270,000 − 60,000) / 60,000 × 100% = 350%.

What the table tells you:

1. Meta quizzes deliver the cheapest leads (UAH 100) but the most expensive patients (UAH 1,667) because so few leads convert to payment.
2. Organic brings the cheapest patients, but its volume doesn't scale quickly.
3. Referrers and Google Ads have the same CAC, but referrers send fewer leads with a much higher conversion rate. It's worth checking whether the partner network can be expanded.

Strictly speaking, ROMI should be based on gross profit (revenue minus direct treatment costs) rather than revenue. Revenue is fine for comparing channels with each other, but use profit when deciding whether advertising pays off.

CAC vs. LTV: how much can you pay for a patient?

CAC on its own doesn't tell you whether a number is high or low. You need to compare it with what a patient brings in over the whole relationship — the lifetime value (LTV).

LTV = average ticket × average number of visits over the patient's lifetime × margin

A hypothetical example: average ticket UAH 6,000, the patient comes 3 times on average, margin after direct costs is 40%. LTV = 6,000 × 3 × 0.4 = UAH 7,200.

In our example, fully loaded CAC is UAH 1,298 and LTV is UAH 7,200 — a ratio of about 5.5. The advertising pays off with room to spare. For inpatient facilities, rehab centers and care homes, LTV is calculated from the average length of stay and the monthly fee — the logic is the same.

Why is CAC hard to calculate without a CRM?

The main difficulty is linking spend in the ad account to a payment at the front desk. Between them sit a lead, a call, a booking and a visit — sometimes weeks apart and across several touchpoints.

Without a system, clinics run into the same problems:

1. Calls with no source. A patient saw an ad and called, but the front-desk log doesn't record where they came from.
2. Repeat inquiries. A patient submitted a quiz, then a week later called from a Google ad. Which channel brought them in?
3. Payments in a separate system. The till or the clinical records system doesn't know the patient's source.
4. Manual reconciliation. Once a month the marketer merges three spreadsheets — late and with errors.

The answer is end-to-end marketing attribution: the source is captured when the lead comes in and stays with the patient all the way to payment.

In 95sales CRM, the website tracking code remembers which ad brought the visitor (UTM tags, a Google Ads or Meta click), even if they submit the form later. Leads arrive with their source, calls from Binotel and Ringostat (Ukrainian telephony providers; others connect through a generic webhook) are matched to the record by phone number, and the patient's payments land on the same record. The analytics section shows conversion and revenue by source, average ticket and LTV, filterable by brand, website and manager.

How often should you calculate CAC, and over what period?

Calculate CAC regularly, over a period that matches how long patients take to decide. For clinics with quick decisions (a consultation, a one-off procedure), a month is enough. For expensive treatment courses, rehab and care homes, where weeks pass between lead and payment, look at a quarter or attribute each patient to the month of the lead rather than the month of payment.

Practical rules:

1. Calculate monthly, decide quarterly. Monthly swings can be random; a quarterly trend is more reliable.
2. Separate new patients from returning ones. A repeat visit from a patient acquired a year ago shouldn't make today's advertising look cheaper.
3. Don't compare channels with different cycles head to head. Search ads bring people ready to book today; content and social bring people who will decide in a month.
4. Log your changes. If you changed prices, the call script or the website, note the date — otherwise you won't know why CAC moved.

Common mistakes when calculating CAC

1. Dividing by leads instead of patients. That's CPL, not CAC, and it says nothing about money.
2. Counting only the ad budget. Without the agency, call center and tools, CAC looks lower than it is.
3. Counting returning patients as new. This artificially makes advertising look cheaper.
4. Losing calls. If calls aren't tied to a source, phone patients end up under "unknown source" and channel CAC gets distorted.
5. Looking at CAC without LTV. An expensive patient on a long treatment course can be worth more than a cheap one-off consultation.

How to reduce patient acquisition cost

There are two ways to lower CAC: spend less on ads, or turn more leads into patients. The second is almost always cheaper.

1. Speed up first contact. The faster you call back, the higher the lead-to-contact rate. See the guide on missed calls.
2. Review front-desk calls. A weak conversation is the most common reason a lead is lost after contact.
3. Reduce no-shows. Confirm appointments and give clear instructions for the visit.
4. Reallocate budget by CAC, not CPL. Cut channels with expensive patients, even if their leads are cheap.
5. Work your existing base. A repeat visit from an existing patient costs less than a new one.
6. Grow your referrers. Partner referrals often convert at a high rate.

Each of these points is about your sales pipeline, not the ad account. For how CAC fits into the clinic's overall metrics, see the guide to clinic KPIs and unit economics.