If you price by gut, you sometimes work hard and earn little. If you price too high, the job goes to someone else. The real question most of us face: take the job on a day rate, or give a fixed price?

Here’s a simple way to choose, a quick calculator you can copy, and exact words to use with clients. We’ll also show where VAT at 10%, 5.5%, or 20% fits so your numbers are solid.

When day rate wins

• Unknowns behind walls (old pipes, bad wiring, surprises)
• Client can’t decide finishes yet
• Small fixes that grow on site
• You need the client present to choose and sign off daily

When fixed price wins

• Scope is clear with a proper walkthrough and photos
• Materials and quantities are stable
• You want clean milestones and predictable cash flow
• You’re competing and the client wants apples-to-apples

The quick margin calculator (copy/paste)

Use this to sanity-check your price. Swap inputs for your job.

# Inputs (edit to your job)
materials_eur = 1900
labour_days = 6
day_rate_eur = 380
overhead_pct = 0.12      # shop, travel, small consumables
risk_pct = 0.08          # unknowns, rework, delays
target_margin_pct = 0.20 # your profit target
vat_rate = 0.10          # 10% renovation; 0.055 energy; 0.20 new build

# Calculations
labour_cost = labour_days * day_rate_eur
materials_with_overhead = materials_eur * (1 + overhead_pct)
risk_buffer = (labour_cost + materials_with_overhead) * risk_pct

fixed_price_before_margin = labour_cost + materials_with_overhead + risk_buffer
fixed_price_with_margin = fixed_price_before_margin * (1 + target_margin_pct)
fixed_price_TTC = fixed_price_with_margin * (1 + vat_rate)

day_work_total_HT = labour_cost + materials_with_overhead
day_work_TTC = day_work_total_HT * (1 + vat_rate)

print(f"Fixed price HT: €{fixed_price_with_margin:,.0f}")
print(f"Fixed price TTC: €{fixed_price_TTC:,.0f}")
print(f"Day work HT (est.): €{day_work_total_HT:,.0f}")
print(f"Day work TTC (est.): €{day_work_TTC:,.0f}")

Example: bathroom refresh (plumber + tiler)

• Materials €1,900 (fittings, tile, glue)
• 6 days on site at €380/day
• Overhead 12%, risk 8%, margin 20%
• Renovation VAT 10%

Results (rounded):

• Fixed price ≈ €5,713 HT, €6,283 TTC
• Day-work estimate ≈ €4,408 HT, €4,849 TTC

How to read it:

• Fixed price covers risk and your margin. Great if scope is locked.
• Day work is cheaper on paper but blows up if the client hesitates or surprises bite.

Price it fast in Donizo (and keep the maths straight)

If you’re still crunching this on paper or in notes, you’ll miss something.

• Speak your scope; AI turns it into quote lines
• Pick 10% / 5.5% / 20% VAT per line and Donizo totals it right
• Save common items (e.g., “WC set + install”, “radiator swap”)
• Send a clean proposal and track “sent, seen, accepted”

Try it in Donizo and stop retyping the same lines every week.

Invoice strategy that fits your choice

If you go fixed price

• Ask 30–40% deposit to cover materials
• Bill a mid-job milestone (e.g., after rough-in or after paint 1st coat)
• Balance at handover; list any snag items clearly

If you go day work

• Daily timesheet + materials photo, client initials each day
• Weekly invoice so cash doesn’t lag three weeks
• Cap per week (e.g., “up to 4 days unless agreed”) to avoid surprises

VAT reminders

• 10%: most renovation labor and materials in an existing home
• 5.5%: energy improvement (insulation, eligible HVAC) per official criteria
• 20%: new construction, supply-only items, or non-eligible work
• Mixed job? Use different VAT per line. Example: insulation at 5.5%, painting at 10%, a supply-only appliance at 20%

Do it cleanly in Donizo

• Split VAT per line; Donizo totals HT/TVA/TTC correctly
• Turn accepted quotes into invoices in one click
• Track payments and see who still owes what
• Automatic (polite) reminders so you don’t chase by hand

All of that is built into Donizo. No more spreadsheet gymnastics.

Scripts you can copy

Offer both options (email or SMS)

Hi [Name],
Your job can work in two ways:
1) Fixed price: covers known tasks + a risk buffer, billed in 2–3 stages.
2) Day rate: €[rate]/day + materials at cost + 12% overhead, billed weekly.
Given the unknowns (old pipes/hidden cables), I recommend [option].
Reply “OK” and I’ll send the proposal.
—[Your Name]

Daily check-in for day work

Quick recap for today:
- Hours: 7.5
- Tasks done: [e.g., strip old tiles, reroute drain]
- Materials used: [photos attached]
- Plan for tomorrow: [e.g., set tray, waterproof]
Please reply “OK” to confirm.

Quick checklist before you price

• Walk the job and open at least one “problem area” (a tile, a socket, a trap)
• Write down decisions still pending (color, layout, model) — that’s risk
• Choose: if 3+ unknowns, go day work or pad risk in fixed price
• Add overhead (consumables, travel, admin) — don’t pretend it’s zero
• Apply correct VAT per line
• Put payment stages in the proposal

Wrap up

Pick the method that matches risk and client behavior. Use the calculator to sanity-check your margin. Keep proof daily if you go day rate.

When you’re ready to stop juggling apps and paper, run the whole flow — quote by voice, proposals, VAT-correct invoices, payment tracking, job status, and client notes — in Donizo.