Measurement Conversion

I measured on a wrong scale, I used a 1 inch to one inch scale but what i needed was a 1 inch to 20 foot scale. is there any way i can go back and change the measurement scale on what I did? or do I have to remeasure everything? for example i had one measurement i measured out that was 13.58 square inches but when I used the correct scale it was 5493.15 square ft so is there a conversion I can do?