How much does a PHP upgrade cost?
It depends on the application, not the PHP version. Here's what drives the price and how to read a quote.
Nobody can honestly quote a PHP upgrade for an application they haven't looked at. A small, well-kept site and a large, untested system can sit on the same PHP version and differ by a factor of ten in effort.
What follows won't give you a number to quote back to a supplier. It will tell you what moves the price, what to expect from a good quote, and how to avoid being surprised.
Book a free conversationLegacy System Assessment, from £2,500
My published prices
| Price | |
|---|---|
| Initial conversation | Free |
| Legacy System Assessment | From £2,500 (larger systems typically £4,000-£7,500+) |
| Direct development and consultancy | £950 per day |
| Urgent / recovery work | From £1,300 per day |
| Agency / white-label | From £1,150 per day |
All prices exclude VAT. Full pricing
The usual route: a free conversation, then an assessment that maps what the upgrade involves, then a fixed-price quote for the work. You're never committed beyond the assessment.
What drives the price
| Factor | Why it matters |
|---|---|
| How far behind you are | PHP 7.4 to 8.4 is a very different job from PHP 5.3 to 8.4. Each version in between changes things |
| Size of the codebase | More code means more to check, and more places for old behaviour to hide |
| Framework and CMS | An upgrade may need a framework upgrade too. Laravel upgrades |
| Third-party packages | Abandoned or incompatible packages are the most common cause of overruns. Each may need replacing |
| Tests | With none, I must build a safety net before changing anything. That's a cost, and it's also what makes the upgrade safe |
| Documentation | The less that exists, the more investigation is needed |
| Database | An old MySQL or MariaDB version may need upgrading alongside |
| Integrations | Payment, email, APIs and scheduled jobs each need checking |
| Server complexity | One server, or several? Queues, caches, multiple environments? |
| Urgency | Emergency work costs more than planned work |
| Business risk | A system handling payments or personal data needs more care and more testing |
How the arithmetic works
At my published day rate of £950, the maths is simple: a 5-day piece of work is £4,750, and a 10-day one is £9,500, plus VAT.
This is an illustration of the arithmetic, not a quote. Real work is priced fixed after the assessment, for the reasons above. But it shows why a small application can be a modest project and a large untested one can be a substantial one.
What else costs money
Some costs don't appear in the developer's quote. Ask about them.
- Hosting. A new server or plan, if you're moving. Paid to the host, not to your developer. Hosting migration
- Licences and third-party services. Paid plugins, commercial libraries and software licences may need renewing or replacing.
- Replacing abandoned components. Sometimes there's a new package to pay for.
- Your own team's time. Someone needs to test the upgraded system and sign it off.
- Content and data clean-up, if the upgrade shows problems in old data.
- Ongoing maintenance. An upgrade that isn't kept up simply starts the clock again. Ongoing care
The cost of not upgrading
Doing nothing isn't free. It's a cost you haven't been invoiced for yet.
- Security risk. Unsupported versions don't get fixes, and attackers scan for them
- A forced move. If your host drops the version, you pay for an emergency at emergency rates. Host ending support
- Failed audits and insurance problems. Cyber Essentials and insurer questionnaires
- A bigger jump later. Every year you wait adds more to change
- Slower, costlier development, because modern tools and packages won't run
Planned work is almost always cheaper than emergency work.
How to read a quote
A good quote for an upgrade should tell you:
- What version you're on and what it will move to, and why that target
- What was examined before the price was set
- What's included: PHP, framework, packages, database, server, testing, documentation
- What's excluded: third-party costs, replacement packages, extra environments
- How testing works, and what safety net exists
- What happens if it turns out harder than expected
- The rollout plan and how you'd roll back
- Whether it's fixed price or time and materials, and what triggers a change in price
- Who does the work, and what happens if they're ill or unavailable
Be wary of: a price with no assessment behind it; "it'll be quick" for an application nobody has opened; no mention of tests or rollback; a quote that rewrites the whole thing when you asked for an upgrade. Rewrite vs refactor vs upgrade
How to keep the cost down
- Start before the deadline. Planned work is cheaper than emergency work.
- Get the assessment done. It prevents the expensive surprises.
- Do it in stages. Upgrade the highest-risk systems first.
- Fix the package problem early. Replacing abandoned components is a large part of many upgrades.
- Keep it current afterwards. A small annual step is much cheaper than a five-year catch-up.
- Provide access and decisions promptly. Delays cost money.
Why AI helps with the cost
A large part of the traditional cost of an upgrade was investigation: finding what would break, in which files, and why. AI-assisted analysis cuts that, so more of the budget goes into fixing and testing, and less into searching. It doesn't remove the need for testing and review. That's where the care, and the cost, belongs. How I use AI
Frequently asked questions
Can you give me a price without an assessment?
For a simple, well-defined situation, sometimes. For an unfamiliar application, I'd be guessing, and guessed quotes tend to end badly for one side. The assessment is how we both get a reliable number.
Is the assessment cost deducted from the upgrade?
That's a conversation for when we speak. What I can say is that the assessment is a defined piece of work, and the report is yours to use with me or anyone else.
Is it cheaper to rewrite?
Rarely. A rewrite costs more upfront, takes longer, and loses embedded knowledge. Rewrite vs refactor vs upgrade
Why is an urgent upgrade more expensive?
It means reprioritising other work and often working at short notice. Urgent work starts from £1,300 per day, subject to availability.
Do agencies pay more?
Agency work is from £1,150 per day, which reflects the extra coordination and overhead involved. Agency terms
What about VAT?
Prices exclude VAT, which is added at the applicable rate.
Tell me what you've inherited.
Tell me your PHP version, your framework and what's worrying you. I'll tell you honestly what an upgrade involves, and what an assessment would find.
Book a free conversationLegacy System Assessment, from £2,500