Examples:

  1. {{Evaldemo|CURRENTDAY|s=is}} displays
    {{CURRENTDAY}} is 22
  2. {{Evaldemo|#expr:2*3}} displays
    {{#expr:2*3}} gives 6
  3. {{subst:evaldemo|subst=subst:|#expr:2*3}} gives:
    {{ subst:#expr:2*3}} gives 6
  4. {{Evaldemo|1=#expr:2+2=5}} displays
    {{#expr:2+2=5}} gives 0
  5. {{Evaldemo|1=#expr:(2+2=4)|s==}} displays
    {{#expr:(2+2=4)}} = 1
  6. {{Evaldemo|urlencode:!|s==}} displays
    {{urlencode:!}} = %21
  7. {{Evaldemo|uc:abc}} gives
    {{uc:abc}} gives ABC
  8. {{subst:Evaldemo|uc:Upper Case|subst=subst:}} substitutes
    {{ subst:uc:Upper Case}} gives UPPER CASE
    See Help:Substitution for several caveats wrt subst=subst:.

As always the expression (first parameter) cannot directly contain "|", "=", plus other special cases related to square brackets / curly braces. In the case of this template "not directly" means "never" except from "=" as shown above.

For simple nested expressions use Template:Evaldemo/2 (edit talk links history):

  1. {{evaldemo/2|#expr:4*|#expr:not 0| >3 | s=yields}} displays
    {{ #expr: 4*{{ #expr:not 0}} >3 }} yields 1
  2. {{evaldemo/2|urlencode:|DIRMARK}} displays
    {{ urlencode:{{ DIRMARK}}}} gives %E2%80%8E