Couple of month before I committed one project to remove bug from that software, that project is not developed according to customer requirements. So, I have included some advanced function according to customer requirement like "report generation", "customization".

However, there are some bug in logic of coding and also in database construction. I changed everything. now, I am in final stage of that project. But I don't know how to estimate cost for all those process. I am doing this project as my part time work. Could anyone suggest me, how to estimate cost for my work?

  • a lot depends what you agreed with your client. For example, When you started the project did you agree that it would cost $1000 dollars no matter how long it took? Or did you say that it would take 100 hours or 25 days?
    – Willl
    Aug 20, 2013 at 13:02
  • ya. i told them it will take month,actually, i committed that project to remove bugs in limited area. but, it have bugs in all over the project. so, i dont know how to fix rate and its extending more than two month.
    – Dineshcool
    Aug 20, 2013 at 15:39

2 Answers 2



"How much should I charge?" would be off-topic. Calculating costs, especially retroactively, should be a straightforward formula based on your contract with the client.

Calculating Costs

There are generally three kinds of rates:

  1. Fixed rates, where you and the client have agreed on a scope and a price ahead of time.
  2. Time and materials, in which a fixed labor rate is multiplied by the man-hours consumed by the project. The cost of externalities such as equipment, consumables, or travel expenses are generally billed as separate line items from the labor.
  3. Receipts made, in which you pass your actual costs onto the customer directly, plus any agreed-upon discount or mark-up.

If your contract specifies a fixed rate, then you can't change the price; your primary project controls are scope and volume, which you can't really manage retroactively. True fixed-rate contracts shouldn't involve any calculations, since the rate has already been agreed-upon ahead of time. However, if your "fixed rate" is based on some kind of piece-work, then you would calculate UnitRate x UnitsCompleted.

If your contract is for time and materials, then you normally calculate (LaborRate x Hours) + Expenses to arrive at the cost. If your contract is on a receipts-made basis, then you typically calculate MoneySpent + NegotiatedMarkup.

Read Your Contract

In your specific case, you've already done the work. Presumably, you didn't do the work before negotiating an agreement with the client, and you should therefore have a written agreement or signed contract that spells out how you may charge for the work performed and how those charges should be calculated.

While there are some standard ways to charge for projects, a contract can specify any billing structure you and the client agree upon. As a result, you need to refer to your contract to determine how costs for the project should be calculated and billed.


Yes, "time & materials" PMI contract types since you have completed the work and should be able to derive the time you incurred making this change.

Now, if your client and yourself have already agreed to a fixed price contract and there is no signed-off change request you may be on the hook for the cost.

I would try to work it out with your client using your; rate * hours took.

  • Fine. Its based on hour or kind of task.? I am bit confused to fix amount for my project.
    – Dineshcool
    Aug 18, 2013 at 13:32

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