An uncertainty estimation needs to be well documented so a persone many years later can read it and follow the reasoning, The three softwares recommended below give detailed reports and it is easy to follow the calculations. NOTE GUM workbench is not a free software , but there is a demo version if you want to try it out.

MUkit (Measurement Uncertainty Kit) is a measurement uncertainty software application, its calculation are mainly based on the handbook Nordtest TR537 and ISO 11352. It is a user-friendly tool, where a laboratory can utilize results from quality control samples and validation data for uncertainty estimation. MUkit software is available for download at Envical SYKE website. For calculations of absolute uncertainty, in concentration units, you need to choose the Test version. An example of a MUkit report is given in here.

GUM workbench - The software GUM Workbench from Metrodata is based on the ISO Guide to the Expression of Uncertainty in Measurement and implements a systematic way to analyse an uncertainty problem for single and multiple results. It, or some other modelling software can be recommended when

  1. the uncertainty estimation based on validation and QC data is not possible and
  2. the uncertainty components are in different units.

If the uncertainty components are in the same units one can often use EXCEL for uncertainty estimation e.g. temperature measurements. 

An Excel sheet for estimating the measurement uncertainty following the procedure described in ISO 11352 and the Nordtest TR537 was created by Michael Koch from the University of Stuttgart. In the Excel  sheet the procedures and requirements of ISO 11325 were transferred one by one. The design of the sheet is suitable for using a printout directly as documentation of the calculations. Two versions are available, where one is using relative figures (measurement uncertainty in %) and the other absolute figures (e.g. in concentration units). The sheets can be found here.