We aim to establish traceability at calibration and hence to en- able a certified flow measurement with a calibrated measure- ment system. A new calibration method is presented for laser velocimetry. We develop a simple, unique method which estab- lishes traceability of its uncertainty. The device is transportable and calibratable by any users for their own instruments on-site. Our new method requires only a rotating disk and a precision lin- ear stage providing positional information. In former calibration methods, the uncertainty of the orbit radius of a scattering object was dominant due to the difficulty of accessing the true center of the rotation. The diffuculty was solved in our new method. The new method provides an accurate estimate of the orbit radius and hence the velocity of the calibration object through a linear re- gression. The calibration constant is obtained even without the need of direct access to the absolute value of the rotation radius. The uncertainty budget is examined throughout the calibration procedure. The traceability chain is established once the trace- abilities are maintained to the translation stage and the motor used for rotating the calibration disk. The new method has been realized with three different calibration setups and their perfor- mances were investigated. We demonstrate that the new calibra- tion method can achieve uncertainty down to 0.1 %.