Home > Personal > Personal Lending > Mortgage > Mortgage Resources > Glossary > Fixed Installment Fixed Installment November 9, 2021 The monthly payment due on a mortgage loan which includes both principal and interest.You Might Also Like: Living QuartersSpring Maintenance Checklist for Your Home All Things CommunityHoli-days of Giving 2022 Everyday MoneyGiving Back During the Holiday Season Living QuartersYour Top Mortgage Questions Answered Living QuartersHow to Understand Mortgage Language