A method for measuring the flow rate (W HPTACC ) of cooling air in a cooling air circuit of a casing of a high-pressure turbine of a turbomachine , characterized in that measurements are made at least - by a first sensor of pressure, disposed at a fan inlet of a fan of the turbomachine , of a total pressure (PT2) at the fan inlet, - by a second sensor of pressure, disposed at an outlet of a high-pressure compressor of the turbomachine, of a static pressure (Ps3) at the outlet of the high-pressure compressor , - by a fifth sensor of rotational speed of a low-pressure shaft , of a rotational speed (XN12) of the low-pressure shaft , - by a sixth sensor of rotational speed of a high-pressure shaft , of a rotational speed (XN25) of the high-pressure shaft , - by a seventh sensor of the degree of opening of at least one valve of the cooling air circuit (HPTACC), of a degree (T014) of valve opening of the cooling air circuit , a computing unit computes the flow rate (W HPTACC ) of cooling air as a function of at least the total pressure (PT2) at the fan inlet, of the static pressure (Ps3) at the outlet of the high-pressure compressor , of the rotational speed (XN12) of the low-pressure shaft , of the rotational speed (XN25) of the high-pressure shaft and of the degree (T014) of valve opening of the cooling air circuit . measurements are made at least - by a first sensor of pressure, disposed at a fan inlet of a fan of the turbomachine , of a total pressure (PT2) at the fan inlet, - by a second sensor of pressure, disposed at an outlet of a high-pressure compressor of the turbomachine, of a static pressure (Ps3) at the outlet of the high-pressure compressor , - by a fifth sensor of rotational speed of a low-pressure shaft , of a rotational speed (XN12) of the low-pressure shaft , - by a sixth sensor of rotational speed of a high-pressure shaft , of a rotational speed (XN25) of the high-pressure shaft , - by a seventh sensor of the degree of opening of at least one valve of the cooling air circuit (HPTACC), of a degree (T014) of valve opening of the cooling air circuit , - by a first sensor of pressure, disposed at a fan inlet of a fan of the turbomachine , of a total pressure (PT2) at the fan inlet, - by a second sensor of pressure, disposed at an outlet of a high-pressure compressor of the turbomachine, of a static pressure (Ps3) at the outlet of the high-pressure compressor , - by a fifth sensor of rotational speed of a low-pressure shaft , of a rotational speed (XN12) of the low-pressure shaft , - by a sixth sensor of rotational speed of a high-pressure shaft , of a rotational speed (XN25) of the high-pressure shaft , - by a seventh sensor of the degree of opening of at least one valve of the cooling air circuit (HPTACC), of a degree (T014) of valve opening of the cooling air circuit , a computing unit computes the flow rate (W HPTACC ) of cooling air as a function of at least the total pressure (PT2) at the fan inlet, of the static pressure (Ps3) at the outlet of the high-pressure compressor , of the rotational speed (XN12) of the low-pressure shaft , of the rotational speed (XN25) of the high-pressure shaft and of the degree (T014) of valve opening of the cooling air circuit . <EOS>