# Winch Size Calculator

URL: https://speedycalculator.com/calculators/everyday-life/winch-size/
Last updated: 2026-10-25

> The winch size calculator estimates the line pull needed to recover a stuck vehicle from its weight, the ground it is stuck in, the slope and any damage, and recommends a winch rating with a safety margin.

## Inputs

- Vehicle gross weight (lb, kg, g, oz)
- Ground conditions
- Slope angle (°)
- Extra resistance from damage (e.g. locked wheels) (lb, kg, g, oz)

## Results

- Rolling / bogging resistance
- Gradient resistance
- Required line pull
- Recommended winch rating

## Formula

```
Rolling resistance = weight ÷ ground factor (road 25 … bogged to the bonnet 0.33)
Gradient resistance = 0 (< 15°), ¼ W (15–30°), ½ W (30–45°), W (> 45°)
Required pull = rolling + gradient + damage; recommended winch ≥ 1.5 × required (and ≥ 1.5 × vehicle weight)
```

## Explanation

Off-roaders often choose a winch rated at 1.5 times the vehicle's gross weight. The real pull needed depends on how badly the vehicle is stuck – a car on a paved road rolls easily, while one bogged in mud to the axles needs a pull equal to its own weight. Each layer of rope on the drum also reduces the winch's pulling power.

### How to use the Winch Size Calculator

- **Vehicle gross weight**
- **Ground conditions**
- **Slope angle**
- **Extra resistance from damage (e.g. locked wheels)**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the vehicle weight, choose the ground conditions and slope, and add any resistance from damage (for example a locked wheel).

### Tips

- Use your own measured figures – fuel economy, speed and prices vary a lot with driving style, traffic, load and season.
- Pick the unit in each field's menu (miles or kilometres, mpg or L/100 km); the calculator converts everything for you.
- Fill up to the brim twice and divide the distance by the fuel added to measure real fuel economy.
- For vehicle modifications, treat results as a starting point and confirm with the parts maker or a professional mechanic.

### Common mistakes to avoid

- Mixing US and imperial (UK) gallons – a UK gallon is about 20% bigger.
- Using the advertised fuel economy instead of real-world figures.
- Forgetting tolls, parking and wear and tear when comparing driving with public transport.

### Inputs explained

FieldWhat to enterVehicle gross weightUnits: lb, kg, g, ozGround conditionsChoose one: Paved road (factor 25), Gravel (5), Wet grass (4), Shingle (3) …Slope angleUnits: °Extra resistance from damage (e.g. locked wheels)Units: lb, kg, g, oz

### What each result means

- **Rolling / bogging resistance** = [Vehicle gross weight]÷[Ground conditions]
- **Required line pull** = [Rolling ÷ bogging resistance] + [Gradient resistance] + [Extra resistance from damage (e.g. locked wheels)]
- **Recommended winch rating** = max(1.5×[Required line pull], 1.5×[Vehicle gross weight])

### Example values

How the main result changes when **Vehicle gross weight** changes and everything else stays at the example values above:

Vehicle gross weight (lb)Recommended winch rating (lb)2,5003,7503,7505,6255,0007,5006,2509,3757,50011,25010,00015,000

## Worked example

Inputs — Vehicle gross weight: 5,000 lb; Ground conditions: Mud, sand or soft clay (2); Slope angle: 20 °; Extra resistance from damage (e.g. locked wheels): 0 lb.

Results — Rolling / bogging resistance = 2,500 lb; Gradient resistance = 1,250 lb; Required line pull = 3,750 lb; **Recommended winch rating = 7,500 lb**.

## FAQ

**What size winch do I need?**
A common rule is at least 1.5 × the vehicle's gross weight – a 5,000 lb truck needs a 7,500 lb winch or larger.

**Why does the rating drop as rope winds on?**
The drum diameter grows with each layer, reducing pulling force by about 10% per layer.

**How can I double my pulling power?**
Use a snatch block to make a double-line pull, which roughly doubles the force (at half the speed).

**What formula does the Winch Size Calculator use?**
Rolling resistance = weight ÷ ground factor (road 25 … bogged to the bonnet 0.33).


## Sources

- [Warn Industries – Winching basics](https://www.warn.com/)