A weighbridge gives you one snapshot, one time, if you can find one near your trailhead. Rig-Locker Pro is the vehicle payload calculator app that travels with you instead — it models your load, your center of gravity, and your rollover risk for every trip, not just the one time you happened to drive past a scale.
What This Payload Calculator Actually Does
Most weight calculators are a single input box: type a number, get a number back. This one works differently, because payload isn’t just a total — it’s where the weight sits.
- Vehicle limits, once. Enter your GVWR, curb weight, and GAWR (front/rear) when you set up your rig. Rig-Locker remembers it.
- Load by location, every trip. Add gear, fuel, water, and passengers where they actually sit — roof, bed, cab, trailer.
- Real-time payload vs. limit. See total loaded weight against your GVWR as you pack, not after.
- Center of gravity & stability. Loaded CG height, axle bias (front/rear), Static Stability Factor (SSF), and safe side slope in degrees — calculated from where you actually put things, using the NHTSA SSF formula.
Real Output, Not a Guess
Here’s what Rig-Locker Pro returns on a real build, shown in the dashboard below: a 2025 4Runner Trailhunter, 2 people, 5 days, a 125 lb rooftop tent on the roof, fridge, food, water, recovery gear and kitchen in the cargo area, and duffels on the rear seat.
- Payload used: 469 of 655 lbs available — 72%
- Front axle: 3,083 lbs against a 3,100 lb rating — 99%, 17 lbs of margin
- Rear axle: 3,236 lbs against a 3,500 lb rating — 92%
- Loaded CG height: 31.1 in (stock 30.0 in, estimated)
- SSF 1.08 — ELEVATED on NHTSA’s rollover-star scale
- Safe side slope: 23.6° (half the static tip-over angle — our safety margin)
- Roof load: 125 of 150 lbs
Only 72% of the payload used, and the front axle is already at 99%. That’s why I check each axle, not just the total.
SSF rollover risk calculated with the NHTSA formula. Estimates are for planning — confirm axle weights at a certified scale before departure.
Why This Matters More Than a Total Weight Number
Two hundred miles from help, payload is the whole game — fuel, water, food, spares, recovery gear. Go over GVWR out there and you’re looking at broken springs, blown tires, or a voided warranty. A total weight number tells you if you’re over. It doesn’t tell you if your load is sitting high and off-balance, which is the part that actually causes a rollover.
An Overland Trip Weight Tracker, Not a One-Time Number
Your load changes every trip — different duration, different gear, different passengers. Rig-Locker Pro recalculates payload, CG, and stability for each trip you plan, and it works offline, so it’s with you at the trailhead, not just at your desk.
Get the Payload Calculator
Rig-Locker Pro — $129 one-time, regularly $179 — includes the full payload calculator, center-of-gravity and stability analysis, and per-item placement on a 3-D model of your rig.
Claim Founding Membership — $129. First 150 rigs, then this offer is gone. Or see everything Rig-Locker does.
Want to see this math applied to a specific rig? Jeep Wrangler Rubicon · Jeep Gladiator Rubicon · Ineos Grenadier · Toyota Land Cruiser 250 · Mercedes Sprinter 2500 AWD.