The reliability in strengthening concrete or steel structures using Carbon Fibre Reinforced Polymer (CFRP) depends on the success of the stress transfer between the two materials. This paper presented a simple numerical approach to simulate the stress transfer by applying partial interaction theory. The numerical approach uses a local bond–slip (τ–δ) model obtained from a previous experimental work. Pull tests were conducted on a dog–bone shaped steel specimens to initiate yielding of the steel. Results from the tests and published data compared with the numerical values show good correlations. These provide useful insights in the existence of full and partial interaction regions along the bonded length of the CFRP.