You could check the wire size (usually printed on the side of the wire) inside the Fuse Box...

usually:
Wire size 14 gauge = 15 amps

Wire size 12 gauge = 20 amps
(smaller number = bigger wire)

If you use a bigger Fuse, the wires may not be able to handle it and overheat and ...

if you are unsure, then put a 15A fuse back in it. you never put a larger fuse in, even for a short time. live without it, or kill something else to use another 15A fuse until you can get some more.

BTW, if you are blowing fuses you will want to stock up on them. it means that most likely you are close to the limit of the circuit and until you get things back to a more normal load it will keep happening. if you plugged in a space heater and it blew, then don't plug it in there again. but if you were doing nothing unusual you may have a problem or just too much load. when you replace the fuse this time, check to see what all is dead when the fuse is out. this way you can see if you are just overloading it.

Always replace the fuse with the same size. Without the correct circuit breaker to trip, the wire will heat up. Replacing with a larger fuse allows the wire to exceed its rated amperage load and could start a fire due to excessive heaet build-up.

If you are continuously blowing fuses, you DO NOT want to "stock up on them" as it is an indication of something wrong with your electrical system and should be looked at by a professional.

It could be too many equipment pieces plugged in or a fault in the wiring somewhere.

azlighting, i believe what i said was that to stock up on them until you figure it out. it could be as simple as they have an extra heater plugged in and this is blowing it, or it could be a bad conenction that DOES require someone who can do something other than just unplug something. you don't just assume they have a problem that needs a pro.

how would I know if the one in there was the right size or not? I opened my fuse panel and did not see any wires!

{{gwi:1511352}}

the wires would be behind the Fuse Panel
remove those 2 remaining white screws and take a look.

DON'T TOUCH ANYTHING

sorry, but honestly if you know so little about electricity as to put a bigger fuse than what was there in, then you will not be able to tell at a glance if the wire is #12 or #14. the best thing to do is to assume it is #14 and put a 15A fuse back in there. when you get the money to replace the panel with breakers, have the electrician break any #14 off into smaller circuits to prevent overloads later.

I had assumed the wires would be color coded or marked. I was not planning on switching to breaker box as I have heard that fuses were more reliable. I will get someone to look at the box for me. Thought maybe this was painless. The fuse blew because I had company and had everything on. Not a normal scenario.
Thanks

fuses are not more reliable. if they were better, do you think folks would be using breakers now? nothing wrong with fuses, just old tech and they require you have spares for the "just in case" things.

Whilst new houses are exclusively breakers, many appliances/electronics use fuses, fuses however are not necessarily more reliable (although breakers can be faulty and not trip whereas a fuse properly constructed and sized always will, although they may have more wiggle room)

One downside to fuses is they do age, and can fail spontaneously. If you are not knowingly overloading a circuit and a fuse blows more than once, you have a problem...by the look of OPs panel, it's time for an upgrade if you can afford it. Call an electrician and get that 20 amp fuse out of there immediately. No pennies in there, no Ben Franklin stunts either.