What Is the Exposure Calculator?
The Exposure Calculator is a free online tool designed for photographers who need quick, accurate calculations in the photography space. By entering your aperture, shutter speed, iso, you get instant results including exposure value, approx. illuminance, typical scene. No formulas to memorize, no spreadsheets to build — just enter your numbers and get the answer in seconds. Whether you're a beginner or experienced professional, this calculator saves you time and eliminates guesswork.
Why This Calculation Matters
Getting exposure value right can make the difference between success and costly mistakes. In photography, small errors compound quickly. Manual calculations are error-prone and time-consuming, especially under pressure. This calculator applies proven formulas used by photographers worldwide, giving you confidence that your numbers are correct. Use it to capture better images with precision and avoid common pitfalls that trip up beginners.
When Should You Use This Calculator?
This tool is most useful when you know your aperture and need to find the right exposure value. It's also great for quick estimates before committing to a decision, and to double-check manual calculations or professional quotes, and when comparing different scenarios side by side. Bookmark this page and come back whenever you need a fast, reliable answer — the calculator is always free and requires no signup.
Exposure Calculator
How to Use This Calculator
- Enter Your Aperture (f-stop): Type or select your aperture in the field provided. Use the most accurate value available for best results.
- Enter Your Shutter Speed (seconds): Type or select your shutter speed in the field provided. Use the most accurate value available for best results.
- Enter Your ISO: Type or select your iso in the field provided. Use the most accurate value available for best results.
- Click Calculate: Hit the Calculate button to run the numbers. Results appear instantly below.
- Review Your Results: Check your exposure value, approx. illuminance, typical scene. Use these figures to inform your next decision or compare against alternative scenarios.
How It Works
This exposure calculator uses established formulas to provide accurate results.
The basic rule:
- EV₁₀₀ = log₂(f² / t) – log₂(ISO / 100)
- Equivalent Exposure: EV stays constant when stops balance out
- Approximate Lux ≈ 2^EV × 2.5
Results are estimates based on standard formulas. Verify with current local data for your specific situation.
Tips & Considerations
- Double-check your aperture before calculating — even small input errors can significantly change your results.
- Run the calculator with different values to compare scenarios and find the optimal approach for your situation.
- Pay attention to both exposure value and approx. illuminance — they work together to give you the full picture.
- Bookmark this page for quick access next time you need to capture better images.
- If you're unsure about your iso, start with a conservative estimate and adjust from there.
Frequently Asked Questions
What is exposure value (EV)?
EV is a single number representing a combination of aperture, shutter speed, and ISO. EV 0 equals f/1.0 at 1 second at ISO 100. Each +1 EV halves the light reaching the sensor.
How do I use the exposure triangle?
The three settings — aperture, shutter speed, and ISO — are interconnected. Changing one requires adjusting another to maintain the same exposure. Opening the aperture by 1 stop lets you double the shutter speed.
What EV is needed for outdoor photography?
Bright sunny days are EV 14-16. Overcast skies are EV 10-12. Sunset/sunrise is EV 8-10. Night photography typically requires EV 0 or below.
Is the Exposure Calculator free to use?
Yes, completely free with no signup required. Use it as many times as you need — there are no limits or hidden fees.
How accurate is this calculator?
This calculator uses standard photography formulas trusted by photographers. Results are reliable estimates for planning purposes. For critical decisions, we recommend consulting a qualified professional to verify.