If you have ever typed "how much should I weigh" into a search bar and gotten buried under conflicting medical formulas, ad-laden calculators, and signup walls, you are not alone. The good news: you can run every calculation, tracker, and conversion in your browser, for free, in under a minute. This list rounds up ten no-install tools that cover ideal weight, body composition, hydration, calories, and training math — all client-side, all private.
1. Ideal Weight Calculator ([/tools/ideal-weight](/tools/ideal-weight))
The Ideal Weight Calculator is the fastest way to benchmark your target weight using the three formulas clinicians actually rely on: Devine (1974), Robinson (1983), and Miller (1983). Pick your height, sex, and frame size, and the tool returns a side-by-side range rather than a single number — which is the honest answer, because ideal weight is a window, not a pin on a scale. Use it to set a realistic starting goal before you touch a calorie tracker.
2. Body Fat Calculator ([/tools/body-fat-calculator](/tools/body-fat-calculator))
Weight alone is a noisy signal — two people at 170 lbs can have completely different body compositions. The Body Fat Calculator uses the US Navy tape method (neck, waist, hip) to estimate body fat percentage without a caliper or a DEXA appointment. Pair the result with your ideal weight to figure out how much of your target should be lean mass versus fat loss.
3. Lean Body Mass Calculator ([/tools/lean-body-mass](/tools/lean-body-mass))
Once you have a body fat estimate, the Lean Body Mass tool applies the Boer formula to isolate the weight that is muscle, bone, water, and organs. This number matters more than scale weight for athletes, lifters, and anyone recomping, because lean mass is what drives resting metabolic rate. If your LBM is climbing while your scale weight is flat, you are recomping correctly.
4. TDEE Calculator ([/tools/tdee-calculator](/tools/tdee-calculator))
Your Total Daily Energy Expenditure is the calorie number that keeps your current weight stable. The TDEE Calculator layers your BMR (Mifflin-St Jeor) with an activity multiplier so you can see exactly how many calories per day you burn at sedentary, light, moderate, and high activity levels. From there, subtract 300–500 for a moderate cut or add 200–300 for a lean bulk — no macros coach required.
5. Water Intake Calculator ([/tools/water-intake](/tools/water-intake))
Hydration is the most underrated lever in any weight plan. The Water Intake Calculator converts your body weight, activity level, and climate into a daily ounce or milliliter target. Most people under-drink by 20–30%, and chronic under-hydration mimics hunger, tanks training performance, and bloats your scale readings. Run the calc once, then log it.
6. Daily Water Tracker ([/tools/water-tracker](/tools/water-tracker))
Knowing the target is step one; hitting it every day is the actual work. The Daily Water Tracker gives you a visual water jug that fills as you log each glass, bottle, or cup. Reset is one click, and the entire state stays in your browser — no account, no cloud, no nagging notifications.
7. Calorie to Steps Tracker ([/tools/calorie-to-steps](/tools/calorie-to-steps))
A common question after a heavy meal: "How far do I have to walk to burn this off?" The Calorie to Steps Tracker takes a food, a portion, and your body weight, and returns the steps, miles, or minutes required to break even. It is a behavioral tool more than a math one — seeing "4.2 miles" next to a slice of cheesecake changes the decision in real time.
8. One Rep Max Calculator ([/tools/one-rep-max](/tools/one-rep-max))
Strength training is the single best lever for raising your TDEE without adding cardio volume. The One Rep Max tool estimates your theoretical 1RM from any submaximal set and returns working percentages for hypertrophy, strength, and power blocks. If you train for body recomposition, this is the spreadsheet you will actually open.
9. Running Pace Calculator ([/tools/pace-calculator](/tools/pace-calculator))
Cardio still has a place, and pace is the cleanest way to dose it. The Running Pace Calculator takes a target race time or a known training pace and spits out per-mile and per-kilometer splits for 5K, 10K, half, and full marathon. Use it to plan zone-2 easy runs at an exact pace rather than guessing by feel.
10. What Should I Watch? Quiz ([/tools/what-should-i-watch-quiz](/tools/what-should-i-watch-quiz))
Not every tool on this list is a number cruncher, and that is the point. After you close the trackers, the What Should I Watch? Quiz picks a movie or series based on your mood, runtime budget, and preferred genres. Recovery is part of the plan, and so is rest day entertainment.
How to actually use these tools together
A clean weekly loop looks like this: weigh in, run the Ideal Weight Calculator once a month to confirm your target band, log hydration with the Daily Water Tracker every day, and recalculate your TDEE every time your weight shifts by more than 5–10 lbs. Recheck body fat monthly, not daily — water swings will lie to you. Everything runs locally, so nothing leaves your device unless you copy it out.
FAQ
How accurate is the Devine formula for ideal weight?
The Devine formula was designed for drug dosage calculations and works best for average-frame adults between 5 ft and 6 ft 3 in. It underestimates for tall, muscular frames and overestimates for petite ones, which is why the Ideal Weight Calculator shows Devine, Robinson, and Miller side by side — use the range, not a single number.
Do I need to log calories if I just want to hit a target weight?
Not strictly. If you pair the TDEE Calculator with the Calorie to Steps Tracker, you can eat intuitively and offset overage with movement. Logging is a tool, not a religion — use it for two or three weeks to learn portions, then drop it.
Is my data safe in these tools?
Yes. Every calculator on TinyToolbox runs entirely in your browser. There is no account, no server roundtrip, and no analytics tied to your inputs. Close the tab and your numbers are gone.
Final thoughts
The right ideal weight is the one you can sustain, recover from, and train around. Use these ten tools as a small dashboard — set the target, track the inputs, adjust the plan — and you will outpace anyone relying on memory, vibes, or a single scale number. Open the Ideal Weight Calculator now, lock in your range, and build the rest of the stack from there.