Extension Structural Calculations
for homeowners
(without the faff)

Insured up to £1.5m 

Rapid turnarounds

Money back guaranteed*

Dedicated customer service

Credit / debit cards accepted

ISO 9001 quality certified

IStructE affiliated

*Terms and conditions apply.

“Wonderful efficient and professional service. Great communication and drawings delivered within timescale. Would highly recommend and will use again.”

Maggie, Homeowner

0 +
Projects Since 2012

Calcs-Online: The Scourge of Local Engineers Nationwide

Hear more from our CEO, Sam Dean, about Calcs-Online's mission.

We have a 100% success rate in obtaining building regs approval for our Extension Structural Calculations

How it works...


Upload your architectural drawings using the quote form below


We'll email you a quote usually within 1 working day


Accept the quote terms and conditions using the link that we send


We produce your Extension Structural Calculations

Extension Structural Calculations Quote Form

Extension Structural Calculations
Typical Prices

Mid-Terrace Property

£ 545
  • Standard Service
  • Priority Service +50%

End-Terrace Property

£ 675
  • Standard Service
  • Priority Service +50%

Semi-Detached Property

£ 795
  • Standard Service
  • Priority Service +50%

Detached Property

£ 945
  • Standard Service
  • Priority Service +50%

“Excellent and swift service. They have addressed all our, our architect’s and our builder’s questions in very quick time.”

James Charlesworth, Homeowner