Best Budget Fitness Trackers Under $20 to Help You Monitor Your VO₂ Max Progress

You don’t need a $300 smartwatch screaming at your wrist to know you’re gasping on the stairs. Most people just want something cheap that tracks the basics, doesn’t die in a week, and gives them a sense that their cardio is actually improving. That’s you, right? Watching prices, watching your heart rate, and trying not to get scammed by some $12 “super-smart” band with a pixelated screen and nonsense numbers.

Let’s clear one thing up right away: no fitness tracker under $20 is giving you lab-grade VO₂ max data. Not happening. Some of them will throw a “cardio fitness score” or VO₂ estimate at you, but it’s based on simple algorithms and optical heart rate, decent for trends, not for bragging to a sports scientist.

If you ever want to know your real VO₂ max (the actual amount of oxygen your body can use during hard exercise), that’s where a proper test comes in, mask, treadmill, gas analysis, the whole thing. A performance clinic like Studio Athletica in Toronto literally runs you through a controlled VO₂ max test and gives you exact numbers plus custom heart rate zones you can then use with any cheap tracker. That combo, lab test + budget band, is honestly the sweet spot for people who care about progress but don’t want to live in Garmin land.

Quick Reality Check: What VO₂ Max Actually Is (and What Your $20 Band Can’t Do)

VO₂ max is just a measure of how much oxygen your body can use during intense exercise, usually written as ml/kg/min. Higher number, better engine. Simple idea, big implications.

Improving VO₂ max usually means:

• You can go harder before you feel like you’re dying.
• Easy workouts start to feel genuinely easy, not “this is fine, everything’s fine.”
• You burn more calories at a given pace and handle more training without collapsing.

Here’s the catch: sub-$20 trackers don’t directly measure VO₂ max. They don’t have gas analyzers or advanced algorithms that big brands refine for years. They basically watch your heart rate, your movement, maybe your pace (badly estimated), and then guess how “fit” you are.

So what good are they? Quite a lot, if you use them properly.

• Continuous heart rate , so you can see how hard you’re working.
• Resting heart rate trends , lower over time usually means better cardio fitness.
• Workout duration + rough intensity , enough to run VO₂-max-style training sessions.
• Consistency tracking , days active, steps, total time per week, etc.

That’s your play: use a cheap band to track consistent training that actually pushes your lungs and heart. Use lab testing, or a proper VO₂ assessment app or clinic, when you want the precise numbers and zones.

What to Look For in a Fitness Tracker Under $20 (Without Getting Burned)

Scrolling through Amazon or Temu, you’ll see 50 near-identical bands with slightly different names and photoshop nightmares for product images. Half of them quietly disappear in six months. You don’t need all the fluff.

For under $20, here’s what actually matters:

Non-Negotiable Features

• 24/7 Heart Rate Monitoring If it only measures heart rate when you tap a button, skip it. You want continuous or at least frequent readings to see how your body responds to workouts and recovers overnight.
• Decent Battery Life (5–7 Days Minimum) If you’re charging every two days, you’ll stop wearing it. And then it’s just a very small, very pointless brick in a drawer.
• Usable App (Android/iOS) This one’s sneaky. The hardware might be okay, but the app is garbage, buggy, confusing, no history, no charts. Look for:

• Clear daily/weekly views of heart rate, steps, & sleep
• Workout summaries with duration + intensity
• At least basic export/sync to Google Fit or Apple Health (nice bonus, not mandatory)

• Water/Sweat Resistance IP67 or better is fine. You want it to survive sweat, light rain, maybe a shower. If reviews mention water killing it on day three, that’s your sign.

Stuff You Probably Won’t Get (and That’s Fine)

• Accurate VO₂ max number that matches a lab test
• Proper GPS tracking (you’ll get “connected GPS” at best, using your phone)
• Meaningful sleep-stage accuracy (take “deep/REM” claims with a big grain of salt)
• Serious training load or recovery guidance

Expect “good enough” heart rate and a usable app. Expect some steps, some distance, a few workout modes. Expect trade-offs. You’re paying under $20, not buying a spaceship.

The Best Types of Fitness Trackers Under $20 for VO₂ Max-Oriented Training

I’m not going to pretend there are “official” models that crush everything at this price. These cheap bands rotate constantly, rebranded by different sellers. Instead, think in categories, then you can spot the right thing when it’s on sale or in a lightning deal.

1. The Simple Heart Rate Band (Best for: “Just Track My Effort”)

These are the basic silicone-band trackers you see for $12–$18 with a small rectangular screen and a minimal interface. No crazy features. No fake ECG. Just steps, heart rate, sleep, notifications.

What they’re good for:

• Tracking workout duration and average heart rate
• Seeing your resting heart rate trends over weeks
• Timing intervals without touching your phone

What they’re bad at:

• Exact calorie counts (always off, treat them as estimates)
• “VO₂ max” scores (mostly marketing fluff on these devices)
• Running pace and distance without phone GPS

Look for models that have 4+ stars with hundreds of reviews and a brand that hasn’t just been born yesterday. Bonus if people mention “surprisingly accurate HR” in the reviews.

2. Slim “Bracelet” Trackers (Best for: All-Day Wear & Sleep)

These look more like a thin bracelet than a watch, often marketed heavily toward people who care about comfort or style. Under $20, they’re usually similar inside to the basic bands, just smaller and lighter.

Upsides:

• Super lightweight, easy to forget you’re wearing it
• Battery life can be a bit better due to small display
• Great for people who hate bulky watches

Downsides:

• Smaller screen can make workout timing annoying
• Button/control sometimes fiddly when you’re sweaty and tired

Good for the person who wants passive tracking, steps, resting heart rate, sleep, and just occasional “let me see how hard that run felt” checks.

3. Cheap “Sports Watch” Lookalikes (Best for: Runners on a Tight Budget)

These are the fake-outs that look like mini-Garmins or older Apple Watches. Square or round face, strap with holes, bold colors. You’ll find them around $18–$20, often with “sports mode” options.

Where they shine:

• Bigger display for workouts and intervals
• More visible heart rate numbers while you’re running
• Slightly better workout mode options (running, cycling, etc.)

Where they flop:

• GPS is almost never real (it usually uses phone GPS)
• “Professional sports algorithm” claims are basically comedy

If you’re doing outside walking/jogging and you want something that feels like a “real sports watch” without the price, these can be surprisingly decent, just keep your expectations realistic.

How to Actually Use a Cheap Tracker to Improve VO₂ Max

This is where most people mess up. They buy a tracker, stare at the numbers, and never change what they’re doing. Then they decide the device “doesn’t work.”

The tracker is not magic. It’s a receipt. It tells you how much work you did and roughly how hard it was. That’s it. You’re the one who has to nudge the training in the right direction.

Step 1: Track Your Baseline Week

Before you start going hardcore, just wear the thing for 7 days and don’t change a thing. Let it spy on your normal life.

Write down (or screenshot):

• Average daily steps
• Total active minutes per day
• Average resting heart rate (RHR)
• How many times you did intentional exercise (walk, run, bike, etc.)

That’s your starting point. No judgement, just data.

Step 2: Understand Basic Heart Rate Zones (Budget Edition)

You don’t need lab-level precision to start training smarter. Use this rough guide:

• Zone 1–2 (Easy) – You can talk full sentences, breathing is calm. Great for long walks/jogs.
• Zone 3 (Moderate) – Talking in short phrases, breathing is noticeably heavier.
• Zone 4–5 (Hard to Very Hard) – Few words at a time, legs burning, you’re counting down the seconds.

Cheap trackers often let you set a max heart rate roughly as 220 – your age. Not perfect, but it’s a starting number. Use that to get a ballpark feel for when you’re in easier vs harder territory.

Step 3: Add One VO₂-Max-Friendly Workout per Week

Here are a couple of simple sessions you can run with nothing but a cheap tracker and maybe a timer.

Option A: 4×4 Interval Session

• Warm up: 10 minutes easy (Zone 1–2)
• Then: 4 minutes hard (Zone 4) + 3 minutes easy (Zone 1–2)
• Repeat that hard+easy block 4 times total
• Cool down: 5–10 minutes very easy

Use your tracker to:

• Watch your heart rate climb into that “hard” zone during the 4 minutes
• Make sure you actually recover a bit during the 3-minute easy parts
• Track total workout time, don’t guess

Option B: Progression Tempo Session

• 10 minutes easy
• 10–15 minutes moderate (Zone 3)
• 5 minutes easy

Same idea: use HR + how you feel. Over time, if you can do that same session at the same heart rate but at a faster pace or with less “I’m dying” feeling, your VO₂ max-related fitness is trending up.

Step 4: Watch These Signs of VO₂ Max Progress

Even with cheap tech, you’ll see these shifts if you’re consistent for 6–8 weeks:

• Resting heart rate slowly goes down (train, sleep, eat like a semi-responsible adult).
• Pace at the same heart rate improves (you’re faster for the same effort).
• Recovery between intervals gets easier (heart rate drops faster during the easy parts).
• Workouts feel less murderous at the same numbers on your watch.

None of this requires a fancy “VO₂ max” number on the screen. It just requires honest training and tracking.

When a Professional VO₂ Max Test Actually Makes Sense

There’s a point where “guessing” from a cheap band stops being enough. Usually one of these things is happening:

• You’ve hit a plateau, even though you’re training.
• You’re preparing for a race or serious event and don’t want to wing it.
• You’ve got health concerns (family heart history, weird chest feelings, older age).
• You just want real numbers once, then use your cheap tracker for the day-to-day grind.

A proper VO₂ max test in a performance clinic is a completely different animal from your wristband.

What a lab test typically includes:

• Pre-screening , health questions, risk check, maybe a quick resting measure.
• Treadmill or bike protocol , speed/grade or resistance gradually increases.
• Mask and sensors , they measure how much oxygen you inhale and CO₂ you exhale.
• Heart rate + breathing data , every stage, every minute.

What you walk out with if you go somewhere legit:

• Your true VO₂ max number, not an estimate.
• Ventilatory / anaerobic thresholds , where your body starts going more “anaerobic.”
• Exact heart rate zones tailored to you, not some generic age-based formula.
• Fuel usage report (how much fat vs carbs you burn at different intensities).

Then you take that data and plug it right back into your training. Cheap tracker on your wrist, pro numbers in your head (or on a printout). Great combo.

How to Pair a $20 Tracker with Pro-Level Testing

You don’t have to pick sides, “team cheap tracker” vs “team lab test.” They’re tools, not religions.

Here’s a simple setup:

1. Get a VO₂ max test every 3–12 months if you’re serious about performance or coming back from injury.
2. Get your custom zones , for example:

• Zone 1: <120 bpm
• Zone 2: 120–135 bpm
• Zone 3: 136–150 bpm
• Zone 4: 151–165 bpm
• Zone 5: >165 bpm

1. Program your training around those numbers:

• Most of the week: Zone 1–2 (easy, sustainable work)
• 1–2x per week: intervals and tempos dipping into Zone 3–4

1. Use your cheap tracker to:

• Stay roughly inside the right zone for each session
• Watch how your HR responds as you get fitter
• Track weekly volume (total time, total sessions)

1. Retest in the lab occasionally to confirm your VO₂ max has moved and adjust zones accordingly.

This way, you’re not throwing money at an expensive watch just to get a “maybe” estimate when you could have accurate numbers from a test and cheap hardware doing the grunt work.

How to Avoid Wasting Even $15 on a Garbage Tracker

Under $20, quality is all over the place. Some bands last years. Others barely survive shipping.

Quick filters to save you from trash:

• Review patterns , ignore the first 10 glowing reviews. Scroll to the 3-star and 2-star ones:

• Consistent “HR is way off” complaints? Skip.
• “Died after 2 weeks”? Hard pass.
• “App keeps disconnecting”? That’ll drive you nuts.

• Brand fly-by-night check , if the brand doesn’t seem to exist anywhere else (no basic site, no history, random jumble name), assume no support or warranty.
• Look for actual photos from buyers , especially of:

• The app interface
• The charging connector (some are terrible)
• The strap and buckle (cheap ones snap fast)

• Check return policy , if you can’t easily send it back, that $15 is gone if the band is trash out of the box.

Also, keep an eye on deal timing: Amazon lightning deals, Walmart clearance end caps, even random coupons on AliExpress. That’s how you get a “normally $30” model dipping under $20.

Who Should Stick With Just a Budget Tracker (and Who Should Level Up)

You don’t need to overcomplicate this. Think in terms of goals and personality.

Budget Tracker Only Is Usually Enough If:

• You’re a beginner just trying to move more and breathe easier on the stairs.
• You mainly want to lose some weight, track steps, and improve basic cardio.
• You’re not racing, not chasing PRs, just building a foundation.

For you, the deal is simple: get a band, do 3–4 decent workouts per week (some of them uncomfortable), track your heart rate and time, and watch trends over months, not days.

Adding a VO₂ Max Test Makes Sense If:

• You’re training for a 5K, 10K, half marathon, triathlon, or serious cycling event.
• You feel “stuck” even though you’re logging miles or hours.
• You’ve had injuries, or your body is a bit unpredictable under high effort.
• You enjoy data and will actually use the info, not just frame the report.

In that case, a one-off (or occasional) lab test plus your cheap tracker gives you a training setup that honestly rivals what a lot of mid-level athletes are doing, with way less money spent on gadgets.

Final Thoughts: Yes, a $20 Tracker Can Help Your VO₂ Max, If You Use It Like an Adult

Can a sub-$20 fitness tracker give you a dead-accurate VO₂ max number? No. That’s lab territory. Can it absolutely help you train in a way that improves your VO₂ max and overall cardio fitness? Yes, if you stop obsessing over fake precision and start treating it as a consistency and effort tool.

Here’s the blunt version:

• Buy one decent cheap tracker with continuous HR and a usable app.
• Use it to log 3–4 real workouts per week, some of them hard.
• Watch your resting heart rate, pace at a given heart rate, and recovery between intervals.
• If you ever want the real number and perfect zones, go get a professional VO₂ max test and let that data guide the way you use your cheap band.

The “hack” isn’t the device. It’s combining just enough tech with a bit of structure and a lot of patience. The $20 on your wrist is only as smart as the training you run through it.