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47 free tools · no signup

Free tools for builders

Genuinely useful calculators, generators and SEO & email helpers — all running entirely in your browser. No accounts, no limits, nothing leaves your device.

✓ 100% free✓ No signup✓ Private & local
Calculators

A/B Test Significance Calculator

Free Tool

enter visitors and conversions for each variant to get conversion rates, uplift and statistical significance (p-value).

CalculatorsNo signup

A/B Test Sample Size Calculator

Free Tool

work out how many visitors per variant you need to detect a given uplift at 95% confidence and 80% power.

CalculatorsNo signup

Profit Margin Calculator

Free Tool

enter your cost and selling price to get the profit, margin percentage and markup.

CalculatorsNo signup

VAT & Sales Tax Calculator

Free Tool

add tax to a net amount or extract it from a gross amount at any rate.

CalculatorsNo signup

Payment Fee Calculator

Free Tool

see what Stripe, PayPal or any processor takes from a transaction, and what you actually receive.

CalculatorsNo signup

Discount Calculator

Free Tool

enter the original price and discount percentage to get the sale price and how much you save.

CalculatorsNo signup

Break-Even Calculator

Free Tool

enter fixed costs, price and variable cost per unit to find how many units you must sell to break even.

CalculatorsNo signup

Freelance Hourly Rate Calculator

Free Tool

work out the hourly rate you need to hit your income target after expenses and realistic billable hours.

CalculatorsNo signup

Salary to Hourly Calculator

Free Tool

convert an annual salary to an hourly, weekly and monthly rate based on your real working hours.

CalculatorsNo signup

Dimensional Weight Calculator

Free Tool

enter parcel dimensions and weight to find the billable weight carriers actually charge on.

CalculatorsNo signup

Aspect Ratio Calculator

Free Tool

enter original dimensions and a new width to get the height that keeps the same proportions.

CalculatorsNo signup

Survey Sample Size Calculator

Free Tool

find how many people to survey for a given confidence level and margin of error.

CalculatorsNo signup

Meeting Cost Calculator

Free Tool

enter attendees, hourly cost and duration to see what a meeting really costs in salaried time.

CalculatorsNo signup
Growth & marketing metrics

ROAS Calculator

Free Tool

enter ad spend and revenue to get your return on ad spend instantly.

Growth & marketing metricsNo signup

CAC & LTV Calculator

Free Tool

work out your customer acquisition cost, lifetime value and the all-important LTV:CAC ratio.

Growth & marketing metricsNo signup

Conversion Rate Calculator

Free Tool

enter visitors and conversions to get your conversion rate instantly.

Growth & marketing metricsNo signup

MRR & ARR Calculator

Free Tool

enter your customers and average price to get monthly recurring revenue, ARR and a 12-month growth projection.

Growth & marketing metricsNo signup

Churn Rate Calculator

Free Tool

enter customers at the start and how many you lost to get your churn and retention rate.

Growth & marketing metricsNo signup

NPS Calculator

Free Tool

enter your promoters, passives and detractors to get your Net Promoter Score instantly.

Growth & marketing metricsNo signup

Engagement Rate Calculator

Free Tool

enter followers, likes and comments to get your social media engagement rate.

Growth & marketing metricsNo signup
Content & SEO

SEO Meta Tag & SERP Preview

Free Tool

write your title and meta description with live length checks and a Google search (SERP) preview.

Content & SEONo signup

Readability Checker

Free Tool

paste your text to get its Flesch Reading Ease score, grade level and sentence stats.

Content & SEONo signup

Keyword Density Analyzer

Free Tool

paste your content to see the most-used words and their frequency, so you can check focus without keyword-stuffing.

Content & SEONo signup

Headline Analyzer

Free Tool

score your headline on length, numbers and power words, with tips to make it more clickable.

Content & SEONo signup

Word & Character Counter

Free Tool

paste text to count words, characters, sentences, paragraphs and reading time instantly.

Content & SEONo signup

Colour Contrast Checker

Free Tool

test text and background colours against WCAG AA and AAA accessibility standards.

Content & SEONo signup

Social Share Preview

Free Tool

see how your link will look when shared on Facebook, LinkedIn and X, with title, description and image.

Content & SEONo signup

Social Media Character Counter

Free Tool

see how your post fits the limits for X, LinkedIn, Instagram, Threads, TikTok and Facebook as you type.

Content & SEONo signup

FAQ Schema Generator

Free Tool

turn questions and answers into valid FAQPage JSON-LD you can paste into your page to be eligible for rich results.

Content & SEONo signup

URL Slug Generator

Free Tool

turn any title into a clean, SEO-friendly URL slug (lowercase, hyphenated, no special characters).

Content & SEONo signup

robots.txt Generator

Free Tool

build a valid robots.txt with allow/disallow rules and your sitemap in seconds.

Content & SEONo signup
Email

Email Subject Line Tester

Free Tool

checks length, word count, emoji, ALL-CAPS and spam-trigger words, with an inbox preview.

EmailNo signup

Email Spam Word Checker

Free Tool

paste your email and it flags spam-trigger phrases, ALL-CAPS and excess punctuation that hurt deliverability.

EmailNo signup

Email Format Finder

Free Tool

enter a name and company domain to see the most common professional email formats (first.last@, flast@, and more).

EmailNo signup

Email Signature Generator

Free Tool

fill in your details and copy a clean, professional HTML signature for Gmail, Outlook and more.

EmailNo signup
Generators & utilities

Free QR Code Generator

Free Tool

create a QR code from any text or URL and download it as PNG or SVG.

Generators & utilitiesNo signup

Free Barcode Generator

Free Tool

create CODE128, EAN-13, UPC and CODE39 barcodes in your browser and download them as PNG or SVG.

Generators & utilitiesNo signup

Strong Password Generator

Free Tool

create a random, secure password with adjustable length and character sets.

Generators & utilitiesNo signup

Password Strength Checker

Free Tool

estimates the entropy and rough crack time of a password and tells you how to make it stronger.

Generators & utilitiesNo signup

Favicon Generator

Free Tool

create a favicon from a letter or emoji with your own colours and shape, and download it as a PNG.

Generators & utilitiesNo signup

Colour Palette Generator

Free Tool

pick a base colour and get a matching palette with hex codes for your brand, site or ad creative.

Generators & utilitiesNo signup

CSS Gradient Generator

Free Tool

pick two colours and an angle, preview the gradient live, and copy the CSS.

Generators & utilitiesNo signup

SHA-256 Hash Generator

Free Tool

turn any text into a SHA-256 hash in your browser.

Generators & utilitiesNo signup

Image Compressor

Free Tool

shrink JPG and PNG file sizes in your browser with an adjustable quality slider.

Generators & utilitiesNo signup

Free Invoice Generator

Free Tool

fill in your details and line items and download a clean PDF invoice in seconds.

Generators & utilitiesNo signup

UTM Link Builder

Free Tool

add trackable utm_source, utm_medium and utm_campaign tags to any URL so you can see exactly which campaign drove each visit.

Generators & utilitiesNo signup

Pomodoro Focus Timer

Free Tool

25-minute focus sessions with 5-minute breaks, right in your browser.

Generators & utilitiesNo signup