Daidaitaccen iskar gas yana nufin iskar gas ɗin da ta dace da madaidaicin ma'auni na iskar gas (PV=nRT) ƙarƙashin madaidaicin yanayi (matsi na yau da kullun da zafin jiki, watau 1 atm da 273.15K). Standard iskar gas wani lokaci ne a cikin masana'antar iskar gas. Madaidaitan abubuwa sune ma'auni tare da taro iri ɗaya, kwanciyar hankali mai kyau da ingantaccen ƙima. Suna da ainihin ayyuka na haifuwa, adanawa da canja wurin dabi'u. Ana amfani da su a fagage na zahiri, sinadarai, nazarin halittu da ma'aunin injiniya don daidaita kayan aunawa da matakan aunawa,