It is 4:30 PM on a Friday. A prospective client calls. They have a great idea for a new app and they are excited.

Then comes the question: “We are trying to get budget approval by Monday. Can you give us a rough idea of how much this would cost? Just a ballpark.”

Your stomach drops.

You know that giving a number too early is dangerous. If it’s too high, you scare them off. If it’s too low, you anchor them to an impossible price that will haunt you later.

You know you should do a detailed discovery and build a full Work Breakdown Structure (WBS), but that takes days. You only have 30 minutes before you leave for the weekend.

So, what do you do? Do you just guess a random big number? Do you refuse and lose the momentum?

There is a third option. You can use an estimation technique designed specifically for speed and credible accuracy.

This guide will teach you the mechanics of creating a realistic software ballpark estimate in under 30 minutes, using a method that relies on logic, not luck.

Table of Contents

  1. The dangers of “T-Shirt Sizing”
  2. The Methodology: The “Monster Feature Multiplier”
  3. Step 1: Ignore the Noise (The CRUD)
  4. Step 2: Identify and size the “Monsters”
  5. Step 3: Apply the App Multiplier
  6. Step 4: Add the “Agency Tax” (PM, QA, Risk)
  7. The Walkthrough Example: “Uber for Dog Walking”
  8. How devtimate automates this method
  9. Checklist
  10. FAQ

The dangers of “T-Shirt Sizing”

When under time pressure, many agencies resort to “T-Shirt Sizing.”

They listen to the client and say: “That sounds like a Medium project. Let’s say $50,000.”

This is not estimating; this is guessing based on vibes. The problem with T-shirt sizing is that it is indefensible. If the client asks, “Why is it a Medium and not a Small?”, you have no data to back up your answer. You just have a feeling.

A professional ballpark estimate must be grounded in some form of mathematical reality. It doesn’t need to be precise, but it needs to be logical. You need to be able to show your work.

The Methodology: The “Monster Feature Multiplier”

If you cannot count every single tree in the forest, how do you estimate the size of the forest? You count the biggest redwoods and apply a multiplier.

In software, Pareto’s Principle (the 80/20 rule) applies aggressively. Usually, 20% of the complex features drive 80% of the technical risk and effort.

To get a fast ballpark, we will ignore the 80% of simple stuff and focus intensely on the 20% of complex stuff.

This is the 4-step “Monster Feature Multiplier” technique used by experienced CTOs to gauge projects quickly.

Step 1: Ignore the Noise (The CRUD)

The first step is to look at the client’s brief and mentally cross out everything that is standard, boring software development.

We call this “CRUD” (Create, Read, Update, Delete) or “boilerplate.”

Ignore these for now:

These things take time, yes, but they rarely blow up a budget. They are predictable. Don’t waste your precious 30 minutes trying to count the hours for a “settings page.”

Step 2: Identify and size the “Monsters”

Now, look at what is left. What are the 3 to 5 features that make you nervous? What are the unique selling points of the application?

These are the “Monsters.” They are the features with high technical risk, external dependencies, or complex logic.

Examples of Monsters:

Action: Spend 20 of your 30 minutes estimating only these monsters.

Because you are only focusing on 3-5 items, you can actually give them some thought. Use ranges (Optimistic vs. Pessimistic). If you have an AI estimation tool, use it here to get quick historical data on these specific components.

Step 3: Apply the App Multiplier

Now you have a rough estimate for the hardest parts. But what about the rest of the app? What about all that “CRUD” noise we ignored in Step 1?

We bring it back using a multiplier.

In a typical, balanced application (like a marketplace or SaaS MVP), the “Monsters” usually account for about 30% to 40% of the total development effort. The other 60% to 70% is the glue code, the UI, the standard screens, and the boilerplate.

To get the total development effort, multiply your Monster Total by 2.5x to 3x.

Step 4: Add the “Agency Tax” (PM, QA, Risk)

The number you just calculated (390 hours) is purely for developers typing code in a perfect world.

If you quote this number, you will go bankrupt. You have forgotten the invisible work required to deliver professional software.

You must add the standard agency overhead, often called the “Agency Tax” or load factor.

A safe aggregate multiplier for this is usually 1.4x to 1.5x (adding 40% to 50% on top of development).

You now have a defensible number.

The Walkthrough Example: “Uber for Dog Walking”

Let’s see this in action in real-time. Client wants an app to connect dog owners with walkers, with tracking and payments.

Time starts now (30 minutes clock).

Minute 0-5: Ignore the Noise

Minute 5-20: Size the Monsters

Minute 20-25: Apply Multipliers

Minute 25-28: Apply Agency Tax

Minute 28-30: Create the Range Never give the single number (504). Create a wide range around it (+/- 25%) to show uncertainty.

The Result: You go back to the client and say: “Based on a quick analysis of the heavy lifters specifically the live GPS tracking and split payments projects of this scope typically land between 400 and 650 hours. Depending on our hourly rate, that puts the budget range between $X and $Y.”

You did not guess. You used a logical process that took less than 30 minutes.

How devtimate automates this method

This manual multiplier method works, but it requires experience to know which features are “monsters” and what multipliers to use.

devtimate automates this entire logic chain.

  1. Smart Templates: Instead of starting from scratch, you select a template like “On-Demand Marketplace.” devtimate already knows what the standard “Monsters” are for that project type.
  2. AI Sizing: It uses historical data to provide instant, realistic hour ranges for those complex features.
  3. Automatic Overheads: You pre-configure your “Agency Tax” (PM, QA percentages), and devtimate applies them automatically to every estimate.
  4. Instant Ballpark Ranges: It generates the Optimistic and Pessimistic ranges for you instantly.

You can go from a client idea to a defensible, data-backed ballpark estimate in 5 minutes instead of 30, without needing a senior CTO in the room.

Generate your next ballpark estimate in minutes with devtimate.

Checklist

✅ Never just guess a “T-shirt size” (S/M/L) without data to back it up.
✅ In the first 30 minutes, ignore standard CRUD features (login, profiles, etc.).
✅ Identify the 3-5 “Monster Features” that carry the most technical risk.
✅ Spend your time estimating only those monsters using ranges.
✅ Apply a multiplier (usually 2.5x to 3x) to account for the rest of the application.
✅ Apply a second multiplier (usually 1.4x to 1.5x) for PM, QA, and risk buffers.
✅ Always present the final result as a wide range, not a single number.

FAQ

1. Isn’t this method terribly inaccurate?
It is a ballpark estimate. By definition, it has a high margin of error (usually +/- 50%). The goal isn’t precision; the goal is to establish the correct Order of Magnitude quickly. This method is accurate enough to determine if the client has $50k or $500k, which is all you need at this stage.

2. What if I miss a “Monster” feature?
This is the biggest risk of rapid estimation. If you fail to realize that a specific API integration is incredibly complex, your base number will be wrong. This is why it’s helpful to use a tool like devtimate that has checklists of common complex features so you don’t forget them.

3. Why do we multiply for PM and QA instead of listing them?
At the ballpark stage, you don’t know enough to list PM tasks. Using percentage multipliers (industry standards range from 15% to 25% for each) is the fastest, safest way to ensure you don’t forget these costs.

4. Should I share this calculation method with the client?
No. You share the result (the range) and the assumptions (e.g., “This range assumes standard GPS accuracy, not military-grade accuracy”). You don’t need to show them the kitchen sausage-making of how you applied multipliers.

5. When should I stop using this method and do a real estimate?
Use this method only for the initial qualification call to check budget alignment. Once the client says, “That range sounds okay,” you must stop guessing and move to a Paid Discovery phase to build a detailed, bottom-up WBS before signing a contract.

Creating a quick ballpark estimate doesn’t have to be a stressful guessing game.

By focusing on the few features that matter most and applying logical industry multipliers for the rest, you can generate a credible budget range in under 30 minutes.

Stop guessing, start calculating, and use devtimate to make the process even faster.