3 free calculators

Everyday

Useful tools for travel, household energy and daily choices.

Tools in this category

Estimate fuel required and the total cost of a trip.

Estimate an appliance’s energy use and electricity cost.

Calculate a tip, bill total and amount per person.

Use these focused guides and worked articles to check formulas, assumptions and practical examples.

Everyday

These are the actual formulas used by the linked tools.

L = d × c ÷ 100 · C = L × p

C = (W ÷ 1000) × h × d × p

Tip = bill × rate ÷ 100 · Total = bill + tip

Everyday

Use these worked examples as a reference before entering your own values.

350 × 6.5 ÷ 100 = 22.75 L · 22.75 × €1.80 = €40.95

1,500 ÷ 1,000 × 3 × 30 = 135 kWh

€80 × 18% = €14.40 tip · total = €94.40

Everyday

Keep your starting values, change one input and calculate again. Record both results to see which assumption makes the difference.