Primer3Plus

https://www.primer3plus.com/index.html

NCBI National Center for Biotechnology Information

https://www.ncbi.nlm.nih.gov/

Oligonucleotide ‎‎ Computes

http://biotools.nubic.northwestern.edu/OligoCalc.html

Basic Local Alignment Search Tool

https://blast.ncbi.nlm.nih.gov/Blast.cgi

Molecular Biology Tools

http://molbiol-tools.ca/

Molecular Biology Calculator ‎‎

https://www.promega.com.cn/resources/tools/biomath/