How to Keep a Cash Book for a Small Garage

In a small garage, a lot of money moves without a job card. A five-minute adjustment, a bulb replaced, a top-up of oil; on the other side, lunch, rent, fuel and cash handed to the parts seller. If none of it is written down, the answer to “what did we make today?” is a guess. This guide explains how to keep a simple cash book in a small garage: what to record, how to keep work income apart from other money, and the mistakes that make the evening count go wrong. The method is the same on paper and on a phone.

What a cash book is and why a garage needs one

A cash book is a running list of the money coming into the business and going out of it, in date order. Each line says when, how much, what for and how it was paid: cash, card or bank transfer. The aim is not to do accounting; it is to see where the money goes.

For a garage, a cash book does three things:

• It shows leaks. A gap between the money that should be in the drawer and the money that is there can only be spotted against a written record.
• It makes expenses visible. Lunch, tea, fuel and small parts purchases are tiny one by one, but by the end of the month they add up to a serious figure.
• It measures profit. Take the money out away from the money in and you see what the workshop really earns.

One important note: this book is the business’s own internal record. It does not replace the statutory books or tax records you are required to keep. Ask your accountant what you need for those.

What to record for every entry

A good cash book is short but complete. For each movement, this is enough:

Using the same words every time makes life easier. If one day you write “lunch”, the next “food” and the day after “café”, adding up what was spent on meals at the end of the month becomes a chore. Fix a short list of descriptions you use most: labor, parts sale, oil change, parts purchase, rent, food, fuel, bills, advance.

Keep work income apart from capital and loans

Not every dollar, pound or dirham that lands in the drawer is profit. If a partner puts money into the business, if you borrow from a relative or withdraw cash from the bank, that money comes in, but it was not earned by doing work. Write it on the same lines as work income and your revenue looks bigger than it is, which leads to wrong decisions.

The practical answer is to give every incoming entry one of two types:

• Work income: money for a repair you did, a part you sold or a service you provided. It counts toward revenue and profit.
• Other income: capital, loans, cash taken out of the bank and similar money that does not come from work. It goes into the cash book but is not profit.

The same thinking helps with money going out. Paying the parts seller, rent and wages are real expenses; cash taken from the drawer and paid into the bank is not an expense at all, just a move from one account to another.

Cash book or job card?

The cash book is quick, but it is not right for every job. Knowing when to use which keeps the two records from getting mixed up:

• The cash book is enough for small jobs paid on the spot, where nothing goes on the customer’s account and you do not need to track parts and labor separately, and for the workshop’s own expenses.
• A job card is needed when the car stays in the workshop, parts come out of stock, the customer will pay later, a receipt or invoice must be issued, or you want the work to show in the vehicle’s history. Our guide on how to write a job card covers that side.

The rule is simple: the same money must never be recorded twice. If a payment taken on a job card is already booked, do not also write it in the cash book as work income, or your income will look doubled.

Counting the drawer at the end of the day

A cash book only works if it is checked regularly. The best habit is a short count every evening:

1. Work out the expected cash: this morning’s float, plus today’s cash in, minus today’s cash out. Leave card and transfer payments out of this sum; that money is in the bank.
2. Count the drawer: count the money and compare it with the expected figure.
3. Record the difference: if there is a gap, do not cover it up. Write it as a separate line and note the reason. Most of the time it turns out to be an expense nobody wrote down or a forgotten entry.

Doing this daily sounds like a lot, but if the day’s entries were kept properly, the count takes a few minutes. With a weekly count, finding the reason for a gap is much harder.

Keeping the cash book on your phone

The biggest problem with a paper book is that it stays on the counter. The technician is paid at the lift, means to write it down later and forgets. A cash book kept on the phone misses less, simply because the phone is always in your pocket.

In the Baktam mobile app you tap “Money in” or “Money out” on the home screen. Without opening a customer or a vehicle, you enter the amount on one screen, pick a ready description under “What for?” and mark cash, card or transfer; you can add the plate as a note. You can also tap the microphone and say “tie rod end 120 cash”. Your phone’s own speech recognition writes it down, then simple rules on the phone put the number into the amount, let “cash”, “card” or “transfer” pick the payment method and keep the rest as the description. No AI is involved, and you check everything before saving. For money in you choose “Work income” or “Other income”; only work income counts toward revenue and estimated profit. Today’s money in, money out and the difference stay at the top of the screen. The details are on our cash book app page; for customer payments, receivables and the end-of-day count, see payments and receivables.

Common cash book mistakes

• “I’ll write it up tonight.” Every small movement that is not remembered in the evening comes back as a gap in the count. Record money when you take it or hand it over.
• Not recording money paid out of pocket. If a technician paid the parts seller from his own pocket, that is still a workshop expense; leave it out and profit looks higher than it is.
• Mixing card and cash. Card money is not in the drawer. Without the payment method, the evening count will never match.
• Counting capital as revenue. Money from a partner or a loan is not work income; give it its own type.
• Recording the same money twice. Writing a job card payment into the cash book as income as well inflates revenue.

If you are thinking about moving from a paper book to software, our garage management software page shows how the cash book, job cards, stock and payments work together.