No. A reading of 988°F under your arm is not a fever — it is physically impossible. Normal armpit temperature ranges from 96.8°F to 98.2°F. A reading that high almost certainly means your thermometer is malfunctioning, you misread 98.8°F as 988°F, or the thermometer was not placed correctly.
Here's the thing: your body cannot survive at 988°F. Fatal hyperthermia kicks in somewhere around 108°F to 112°F, when proteins break down and organs start shutting off. Normal armpit temperature sits between 96.8°F and 98.2°F — that's it. So if your thermometer is showing 988°F, something went wrong with the reading, not with your body. The most likely culprits are a cracked digital display, a dying battery scrambling the numbers, or a simple misread. At a glance, 98.8°F and 988°F look surprisingly similar — especially if you're anxious, tired, or checking on a sick kid at 2 a.m. Try again with a thermometer you trust. You're almost certainly fine.
Imagine this: you're checking on your eight-year-old who feels warm. You grab the old thermometer from the medicine cabinet, shove it under her arm, pull it out after ten seconds, and see 988. Cue panic. But here's what actually happened — the battery is nearly dead, the display is showing garbled digits, and you didn't hold it in place long enough. That scenario plays out in households constantly. There are really three things that cause wild readings like this. First, old or low-battery thermometers produce scrambled numbers on digital displays — the segments that form each digit start misfiring. Second, 98.8°F is genuinely easy to misread as 988°F if you glance quickly. Third, armpit readings need one to two full minutes of contact to stabilize. Pull it out early and you'll get a meaningless number. The fix: fresh batteries, a clean dry armpit, a full two minutes, and ideally a backup thermometer to confirm.
People get armpit temperature wrong all the time. Many think it matches your actual core temperature, but armpit readings run 0.5°F to 1°F lower than what you'd get in your mouth. Another myth: every fever needs treatment immediately. A low-grade fever under 102°F actually helps your body fight infection. Then there's the belief that digital thermometers never lie. They're solid when you use them right, but dead batteries, damaged sensors, or factory defects cause wild errors like the 988°F thing. And this one trips people up: oral and armpit readings aren't the same. Oral comes in about 0.5°F higher. Pick one method and stick with it so you can actually track what's happening.
Place the thermometer tip directly in the center of your armpit, then press your arm snugly against your body. Hold it there for a full one to two minutes — not five seconds. Make sure your armpit is dry before you start, because moisture can throw off the reading. Don't peek or shift it mid-reading.
You can, but it's not strictly necessary. Just know that armpit readings typically run 0.5°F to 1°F below oral readings. Rather than doing math every time, pick one method and use it consistently. That way you're tracking real changes over time instead of comparing numbers taken different ways.
Start with fresh batteries and test it on another person. If the readings are still way off, the thermometer is done — replace it. A basic digital thermometer costs just a few dollars and is worth having one you can actually rely on. When you're making health decisions based on a number, that number needs to be right.