Estimate like a boss: predicting your project costs with accuracy

Clients often start a conversation with us along the lines of “we’d like you to build us a new web application”. From there we begin mapping the road ahead, figuring out where we’re going and how best to get there. How well we capture and store this information can make the difference between profit and peril.

There are two important factors to estimating: what needs to be done, and how long it will take. Getting the answers to these questions is crucial to the success of the project.

But time spent estimating work is a cost for your business. It’s time you’re not billing. Here are some of our tips for getting them as close to ‘right’ as possible, without wasting loads of effort.

 What needs to be done?

Do some listening: an aside about how to capture requirements

How to capture project requirements effectively could take days to unpack. However, here are some quick points from our own experience at Error that will help contextualise how to go about it.

  • Listen. Listen hard. Don’t interrupt unless you’ve an important question to ask based on what your client or potential client is telling you.
  • Write down everything you’re hearing. If you haven’t brought a pen and paper (or tablet for notetaking) to a meeting, you’re only half-attending a meeting.
  • Send those notes back to the client to confirm what was said. They’ll often add a little more context or correct what was written, or even add stuff they’ve forgot to mention.
  • All this adds up to creating an open dialogue between your business and a potential customer. This dialogue means that you’re getting all the information you need, and building a relationship at the same time. It’s much easier for a client to agree a project if you’ve demonstrated personal investment in them as people.
  • Finally, are there more than a few people in the room? Consider capturing the requirements in a workshop. This is a core component of how we consult at Error. It’s an essential way to capture requirements when there are different personalities and departments who need input on a project. (You can sell this as a separate service - we sometimes do this1).

Use a template: make sure you track everything which needs doing

One of our secret weapons at Error is process. When we’re doing the same thing more than once, we try to stick to a process wherever possible. Estimating projects is a great example of this: we use one of a handful of templates to make sure we don’t miss stuff when we’re coming up with a price. Unless you’re in a business that bids for wildly different work on each and every project2, you’ll probably also have a mental list of things you always include on an estimate.

There are a couple of things you can do with that list of project tasks. You could include the ones which are relevant for the estimate you’re working on. There’s chance you might forget or miss things by doing that, though. We take the second approach which is to have a template with everything on it, and remove stuff which isn’t relevant.

Of course, there will be requirements in a project that we haven’t encountered before. They normally take up most of our thinking, because our templated list of project tasks just need including without much further thought.

How long is it going to take?

There’s plenty of research and talk to suggest we’re just not very good at predicting how long something will take. Humans are completely inconsistent in the way they interpret time. But there are some techniques to avoid selling work for less than you should have.

Use your template to make it easy for yourself

Our template approach also means you can have effort assigned to your standard tasks, so working out how many days (or weeks, or hours) the project will take is suddenly much less onerous. For example, a line in our workshop template might be:

Workshop (on-site): 2 people x 4 hours

This allows us to be efficient and spend more time thinking about the more complex requirements that we may not have encountered before. These will also become more bespoke line items. If we think we’d do that sort of work in another project, we’ll add the lines to a template.

Have you ever felt that feeling of rising panic when you realise the client thinks they’re getting something which you haven’t costed for? It’s happened to us a few times. It’s always horrible.

The templated list of line items, and the process of elimination, is an important exercise: it means that you have to deliberately take a task out. You don’t have to worry about forgetting to put something in, and hitting a problem later in the project (at your own expense often, too).

You can always tweak things

And of course, even templated line items are changeable. Sometimes we may take three staff to a workshop, or the workshop may take a whole day instead of four hours. The line items are a starting point to costing an estimate as precisely as possible.

Make sure you include contingency

In an earlier article we talked about ensuring that you take into account some contingency: when you’re estimating time for a task, make sure you include extra effort for the situation where things might go wrong. Sometimes, you’ll be really clear about how long a piece of work will take. Other times you won’t be. At Error we often multiply our effort by 1.4 on some lines in an estimate.

Your client might well want a fixed price, so make sure you’re comfortable you’ve included enough 'wiggle room’ in your estimate.

In summary

In hindsight, these tips seem common sense to us - but that wasn’t always the case! It took time to get to grips with estimating, and many companies get it wrong. Here’s a quick summary of this article:

  • Uncover requirements - Create a good dialogue early, use workshops to get to the bottom of the brief and include all stakeholders.
  • Don’t miss anything - Use a template for jobs with common elements. Remove things from this template for each job, rather than starting with a blank slate and trying to remember everything.
  • Include contingency - We multiply by a factor of 1.5.

In the next article, we’ll look at that tricky moment in sales: how to justify your estimate.


  1. Running workshops for requirements gathering will help to cement your relationship with the client. Never do this for free though - if you’re delivering outputs from the workshop, you’re doing work which should be paid for. We’ll cover some techniques we use at Error in a future article. 

  2. …in which case we would argue that you’re not playing to your strengths, and should concentrate on one type of work, or a small range… 

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