How it works
Copy the parts total, billed labor hours and hourly rate from a written estimate for your car. Add a diagnostic fee only if it's listed separately, and type in the tax amount shown on the quote rather than guessing what's taxable. If something is already included in another line, leave it out here. The invoice you get is simple arithmetic on your inputs, not a prediction of what the job should cost.
Subtract only credits that are confirmed and actually reduce the bill. A possible insurance or warranty payout isn't money yet. The contingency is a cushion you pick for your own planning; the shop hasn't charged it, and it doesn't authorize any extra work. Save one quote, then enter another one for the same job to compare them.
The formula behind the estimate
Every result starts with a defined model and visible assumptions.
Labor = quoted billed hours × quoted hourly rate Invoice = parts + labor + separate diagnostic fee + other fees + quoted tax Payable quote = invoice − confirmed credit Additional reserve = payable quote × chosen contingency ÷ 100 Planning budget = payable quote + additional reserve
A worked example
Suppose a quote lists 300 in parts, two billed labor hours at 100 an hour, a separate 75 diagnostic charge, 25 in other fees and 40 in tax. The invoice is 640. With no credit and a 10% reserve, you add 64 and plan for 704. These amounts don't reflect a typical repair price or labor rate anywhere.
Are quoted labor hours the same as the time the car is in the shop?
Not always. Some shops bill a standard labor allowance for the job, and others bill actual time. Use the hours and rate printed on your quote. If the shop gives you one flat labor price, enter one hour and put that total in as the rate, which keeps the math right. If you're unsure, ask the shop instead of working out hours from how long the car sat there.
How do I know the repair is the right one?
This tool has no parts catalog, labor-time database or diagnosis system, so a make, model or symptom can't tell it what repair you need. Get an inspection and a quote from a shop you trust, and consider a second opinion when the work is expensive or unclear. A lower total isn't automatically a better deal if one quote leaves out work the other includes.
What about credits, taxes and cash reserves?
Enter the final tax amount that applies to your quote and location. Find out whether a warranty pays the shop directly or reimburses you later, and put in only reductions that really apply to the bill you'll pay. The calculator doesn't judge whether a repair is safe to skip; that's a conversation with the technician.
Questions worth asking
Does this give repair prices for my make and model?
No. It adds up the amounts on your written quote. It doesn't generate model-specific prices or diagnose any problem.
What if the labor is quoted as one fixed amount?
Enter one billed hour and use the labor total as the hourly rate. Then confirm with the shop exactly what work that price covers.
Should I add sales tax to a quote that already includes it?
No, count tax only once. If the quote's total is tax-inclusive, enter zero in the tax field and keep the other lines as they are.
Is the contingency part of the shop's quote?
No. It's a cash cushion you choose for your own planning, and it doesn't give the shop permission to do extra work.
Can I compare two repair estimates?
Yes. Save the first result, then enter the second quote in the same currency and for the same repair scope. Changing the currency clears the saved comparison.
This is general information, not personalized financial advice. Read the limitations.
