Free Online Calculators — Finance, Marketing, Tax & Fuel
Stop guessing. Start measuring. CalcFuel gives you instant answers on ROI, ROAS, email metrics, social media performance, and more — all free, no sign-up required.
✉️ Email Marketing
View all →Email Open Rate Calculator
Calculate your email open rate from opens and deliveries.
Try it free →Email List Growth Rate Calculator
Track net subscriber growth as a percentage of your list size.
Try it free →Click-Through Rate Calculator
Calculate CTR for ads, emails, and organic search listings.
Try it free →💰 Financial & ROI
View all →Marketing ROI Calculator
Measure the return on your marketing investment.
Try it free →ROAS Calculator
Calculate your Return on Ad Spend instantly.
Try it free →Ad Spend Calculator
Plan your ad budget: clicks, leads, revenue, and ROI.
Try it free →Customer Acquisition Cost Calculator
Calculate how much you spend to acquire each new customer.
Try it free →Customer Lifetime Value Calculator
Measure the total revenue value of each customer relationship.
Try it free →Marketing Budget Calculator
Get a recommended marketing budget based on revenue and industry.
Try it free →Australian Income Tax Calculator
Calculate income tax, Medicare levy, LITO, and take-home pay for 2025-26.
Try it free →GST Calculator
Add or remove GST from any Australian price. Standard 10% rate.
Try it free →Profit Margin Calculator
Calculate gross, net, and operating profit margins instantly.
Try it free →Break-Even Calculator
Find the sales volume needed to cover your fixed costs.
Try it free →Average Order Value Calculator
Track your average transaction size over any period.
Try it free →📱 Social Media
View all →Social Media ROI Calculator
Measure the ROI of your social media ad spend.
Try it free →Social Media Engagement Rate Calculator
Calculate engagement rate for Instagram, LinkedIn, TikTok, and more.
Try it free →Follower Growth Rate Calculator
Track your social media audience growth rate over any period.
Try it free →Social Media Character Counter
Live character count for Twitter/X, LinkedIn, Instagram, and Facebook.
Try it free →Post Length Optimizer
Get optimal length recommendations for every social platform.
Try it free →🎯 Conversion & Leads
View all →Conversion Rate Calculator
Measure how effectively your pages turn visitors into customers.
Try it free →Cost Per Lead Calculator
Calculate your cost per lead and compare across channels.
Try it free →Cost Per Acquisition Calculator
Calculate your cost to acquire a paying customer.
Try it free →Revenue Per Lead Calculator
Find the revenue value of each marketing lead generated.
Try it free →Churn Rate Calculator
Measure how many customers you lose each period.
Try it free →🔍 SEO Tools
View all →Website Speed Impact Calculator
See how faster load times increase conversions and revenue.
Try it free →Website Traffic Calculator
Project organic traffic growth from SEO improvements.
Try it free →Net Promoter Score Calculator
Calculate your NPS from promoter and detractor responses.
Try it free →Marketing Health Check
10-question quiz: score your marketing foundation and get recommendations.
Try it free →🤖 AI Developer Tools
View all →AI Model Router Savings Calculator
See how much you save routing easy queries to cheaper models.
Try it free →Prompt Caching Discount Estimator
Calculate exact savings from caching system prompts with Claude, GPT-4o, or Gemini.
Try it free →Multimodal Payload Estimator
Estimate token counts and costs for images, video, and audio across GPT-4o, Claude, and Gemini.
Try it free →⛽ Fuel & Energy
View all →Trip Fuel Cost Calculator
Calculate total fuel cost for any road trip.
Try it free →Commute Fuel Cost Calculator
See your daily, weekly, and annual commute fuel costs.
Try it free →EV vs Gas Calculator
Compare 5-year or 10-year total cost of ownership.
Try it free →Generator Fuel Calculator
Calculate generator runtime and fuel needed for outages.
Try it free →Fuel Economy Savings Calculator
Quantify savings from improving your driving habits and MPG.
Try it free →Get 10 free AI marketing prompts
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Prompts, playbooks, and bundles for marketers and builders. Instant digital download.
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Every calculator is built with clear assumptions, practical examples, and documented limitations. We publish free tools to help teams make better decisions, faster.
Latest from the Blog
View all →Understanding Fuel Economy: MPG vs L/100km Explained
How to convert between MPG and L/100km, calculate your real fuel costs, and what affects consumption.
Read article →Fuel & EnergyHow to Reduce Your Commute Fuel Costs: 7 Proven Tips
Seven strategies that cut commute fuel costs with real savings estimates for each.
Read article →ROI & AnalyticsA Beginner's Guide to Marketing ROI
The marketing ROI formula, attribution models, channel benchmarks, and common mistakes.
Read article →ConversionWhat Is a Good Conversion Rate? Benchmarks by Industry
Industry benchmarks for e-commerce, SaaS, lead generation, and landing pages.
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