What legacy app modernization costs

$36,000 – $51,000 over 14–20 weeks to rebuild an old office system from scratch and bring every record along. The system priced here runs quotes and orders for an office of about 40 people, and somebody in-house built it about fifteen years ago. The new version is a web app with sign-in, separate screens for the sales desk, the warehouse and managers, search, a few reports, and quotes printed as PDFs.

Keeping part of the old server, it’s 13–19 weeks.

About $2,500 in the middle of the range here. That’s the difference between rebuilding the office system empty and rebuilding it with fifteen years of customers, orders and quotes already in it. The schedule doesn’t move.

The estimator prices the move as planning and integration work. It adds to discovery, it puts an Integrations line on a breakdown that otherwise wouldn’t have one, and it adds nothing to the screens or the server. Connecting to other software goes on that same line.

How the move gets described

“And the old data comes across.” One clause, at the end of the request.

What it turns into

A decision about every field the old system keeps: what it means, where it lands in the new one, and which old records get archived instead of moved. Then the move itself, run again until the counts match on both sides.

Some of what those records mean isn’t in the records. It’s in the old code, in rules like a status of 4 meaning shipped but not billed, or a blank discount column meaning the customer’s still on the old price list. Get those written down while the person who knows them is still around.

Yes, by $7,000 on this rebuild: $30,000 – $43,000 against $36,000 – $51,000. Keep the old database and the records stay put, so you skip the $2,500 move. The other $4,500 is server work the estimator takes off.

When part of a backend already exists, the estimator still prices 65% of the server work, a smaller discount than a finished, documented one gets. Only the server line gets that discount. Planning, design and the screens cost what they would from scratch, and so would the move if the records still had to go somewhere new. It’s $2,500 on this version too.

“We’ll keep the database”

Sounds like most of the server work is already done.

What the estimator prices

65% of the server work still to do, the planning and the screens at full price, and $4,500 off this rebuild.

That saving assumes the part you keep works the way everyone believes. Whenever part of a backend exists, the estimator’s result lists it as an open question, with its own warning: fixing one that half works can add more than starting over, because somebody has to understand the half that exists first.

Leave it alone while it still does the job and the computers it runs on still get security updates. That option costs what you spend on it today, and every figure on this page is money on top of that.

Buying a product can come in under a rebuild too. If what the old system does is ordinary, price the products first. The build-or-buy guide works out the seat count where a build catches up with a subscription, and why the records cost money to move either way.

There are four things you can do with an old system, and the estimator prices one of them.

• 01

  Leave it where it is. There’s nothing to price beyond what it costs you now.

• 02

  Move it to newer servers as it is. That’s hosting and setup work, and the estimator doesn’t price it.

• 03

  Replace it with a product. The subscription is on the vendor’s pricing page, and your records still have to move.

• 04

  Rebuild it, from scratch or on part of the old server. That’s the one the estimator prices.

Start from the old system: every screen, field and report it has today, and which of them people still use. Fifteen years of requests are in there, and not all of them still matter.

Decide what isn’t coming across before anyone prices the rebuild, because everything that comes across gets priced.

Have a sample export of the data on hand, and plan to walk whoever prices it through the old screens. What a studio needs to know to quote you covers the rest.