One of the hardest things about going freelance as a developer isn't writing code — it's knowing what to charge.
Charge too little and you're basically doing a salaried job without the benefits. Charge too much without backing it up and you scare off clients. Most developers I've spoken to either guessed their rate or copied someone else's. Neither is a great strategy.
In this article I want to walk you through exactly how to calculate your freelance day rate properly — based on real numbers, not gut feeling.

Why Most Freelancers Get Their Rate Wrong

The most common mistake is this: taking your old salary and dividing it by 260 working days.
That ignores:

Taxes (you now pay both sides of self-employment tax in the US)
Unpaid days — holidays, sick days, slow months with no clients
Business costs — software, hardware, insurance, accountant fees
No employer pension or benefits — you fund all of this yourself

If you were earning $80,000 as a salaried developer and you divide that by 260, you get roughly $307/day. But that's actually a pay cut once you factor everything in.

The Right Formula

Here's the framework:
Step 1 — Work out your actual billable days
A year has 260 working days. Subtract:

Public holidays (~10 days in the US)
Your own holiday allowance (~15 days)
Estimated sick days (~5 days)
Non-billable time: admin, chasing invoices, marketing yourself (~20 days)

That leaves roughly 210 billable days.
Step 2 — Calculate your real income target
Take what you want to take home and gross it up for tax. If you want $70,000 net and your effective tax rate is around 30%, your gross target is roughly $100,000.
Step 3 — Add your business costs
Software subscriptions, hardware depreciation, liability insurance, accountant — easily $5,000–$10,000/year for a freelance developer.
Step 4 — Divide by billable days
$110,000 ÷ 210 = $524/day
That's your minimum. Price below that and you're losing money compared to employment.

A Faster Way — Use a Free Calculator

If that maths made your head spin, there's a much easier option.
I've been using PayCalcTools' Freelance Day Rate Calculator — it's free, takes about 60 seconds, and handles all the above automatically. You just enter your income target, your country, estimated holidays, and business costs, and it spits out your day rate and hourly rate instantly.
No sign-up. No email required. It also covers UK contractors which is handy if you work with British clients.
You can find the full calculator suite at paycalctools.com — they also have an overtime calculator and a shift differential calculator if those are relevant to your situation.

Should You Charge Daily or Hourly?

Day rate is almost always better for developers. Here's why:

Clients can't nickel-and-dime 15-minute tasks
Easier to scope fixed-price projects from a known daily rate
More professional — larger companies expect day rates, not hourly billing
Protects you when a call runs long or a review takes unexpected time

Charge hourly only when the work is genuinely unpredictable in scope, like ongoing maintenance or bug fixing retainers.

What the Market Actually Pays

To sanity-check your calculated rate against market rates:

Junior freelance developer (1–3 yrs): $250–$400/day
Mid-level (3–6 yrs): $400–$650/day
Senior (6+ yrs): $650–$1,200/day
Specialist (AI, security, platform eng): $1,000–$2,000+/day

These are US figures. UK rates run roughly 30–40% lower in dollar terms but similar in purchasing power.
If your calculated rate falls way below these, something in your cost assumptions is off. If it's way above, you either have very high costs or a very ambitious income target — both worth reviewing.

One More Thing — Review Your Rate Every Year

Most freelancers set a rate and never touch it. Meanwhile inflation runs at 3–5% per year and their effective income quietly drops.
Put a calendar reminder for every January. Recalculate your rate using the same formula (or the calculator above). Raise it by at least inflation. Most clients expect annual rate reviews — it won't surprise them.

Summary

Don't copy a friend's rate or divide your old salary by 260
Factor in taxes, non-billable days, and business costs
Use a proper calculator to get an accurate number fast
Day rates are almost always better than hourly for developers
Review and raise your rate every single year

What's your current day rate strategy? Drop it in the comments — always curious how other developers approach this.

Found this useful? I write about developer career, tools, and productivity. Follow me here on DEV for more.