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Calculation Fields

Build smart forms with live calculations

Add formulas, auto-totals, and scoring to any form. Reference other fields, run arithmetic, score quizzes — all native, no spreadsheet round-trip.

Try It Free See Use Cases
Free on every plan · Visual formula builder · Updates as users type
Quote Calculator
Project type Landing page
Number of pages 5
Add-ons SEO + Analytics
Estimated total
$4,200
Updates as the form changes

A real formula builder, not a code editor

Pick fields from a dropdown, drop in operators, see the result update live. Non-technical creators build formulas in minutes — no syntax to memorize.

  • Click-to-reference any field

    Numeric, dropdown, and choice fields appear in a picker. Pick one, the formula references it by name, no IDs to copy.

  • Standard arithmetic

    Plus, minus, multiply, divide, parentheses for grouping. Order of operations works the way you'd expect from a calculator.

  • Live preview

    See the formula evaluated against test data inside the builder. Catch typos before respondents do.

{pages} × 800 + {addons.cost}
= $4,200

Order forms that add themselves up

Drop a quantity field next to a price, calculation field does the multiplication. Add a discount field, calculation does the subtraction. Respondents see live totals as they shop.

  • Quantity × price

    The standard order-form pattern: per-line subtotals, then a sum field for the order total. Two calculation fields, done.

  • Discounts and surcharges

    Subtract coupon values, add tax or shipping. All calculations server-validated before the payment intent is created.

  • Multi-currency aware

    Calculations run in whatever currency you set on the payment field. The display formats automatically per locale.

T-Shirt 3 × $25 $75.00
Mug 2 × $15 $30.00
Sticker pack 1 × $5 $5.00
Coupon WELCOME10 −10% −$11.00
Total $99.00

Quizzes that grade themselves

Tag answers with point values. The calculation field sums the score. Add a conditional message that shows a pass/fail result based on the threshold you set.

  • Per-answer point values

    Each multiple-choice or checkbox answer gets a point value. Calculations sum the totals automatically as respondents progress.

  • Pass/fail thresholds

    Set a passing score, show different end screens for pass vs. fail. Combine with conditional logic for branching outcomes.

  • Display the score

    Show the final score on the thank-you page or in the email confirmation. Respondents see exactly where they landed.

Q1. Capital of France? +10 pts
Q2. Largest planet? +10 pts
Q3. Year of moon landing? +5 pts
Q4. Speed of light (km/s)? +0 pts
25 / 35
Pass · 71%

Different math for different inputs

Combine calculations with conditional logic to apply different formulas based on what the respondent picks. One field, multiple pricing models.

  • Branch by selection

    If they pick "Premium," apply formula A. If they pick "Basic," apply formula B. The active calculation switches with the selection.

  • Tier-based pricing

    Volume discounts, regional rates, member vs. non-member pricing — all driven by conditions on the calculation field.

  • Hide irrelevant calculations

    Show the right total to the right respondent. Conditional logic toggles which calculation field is visible.

If tier = "Premium" → total = {base} × 1.5
If tier = "Pro" → total = {base} × 1.2
Else → total = {base}

Where calculations earn their keep

Anywhere a form needs to do math — pricing, scoring, sizing, estimating — calculation fields turn a static form into a live tool.

01

Order forms

Multi-product carts that total themselves. Quantity × price per line, sum into a grand total, hand off to Stripe with the verified amount.

02

Quote calculators

Service businesses build instant-quote forms — pages × rate, hours × rate, plus add-ons. Respondents see pricing before submitting.

03

Quiz & assessment scoring

Auto-grade quizzes with point values per answer, show pass/fail results, no manual marking. Pair with assessment mode for proctored exams.

04

ROI & savings calculators

Lead-magnet calculators (cost savings, ROI, payback period) — the kind of interactive content that converts visitors to leads.

05

BMI, dosage, eligibility

Health and fitness forms compute BMI from height/weight. Eligibility checkers compute scores from intake answers. All inline.

06

Pricing estimators

SaaS, agencies, freelancers — show prospects an estimate based on their inputs. Reduces sales-cycle friction by qualifying before the call.

Frequently asked questions

Do I need to know formulas to use this?
No. The formula builder is a visual picker — choose fields from a dropdown, drop in operators, see the result. If you can use a calculator, you can build a calculation field.
Can a calculation reference fields on other pages?
Yes. In multi-page forms, a calculation field can reference any numeric or scored field from any prior page. The total updates as respondents progress.
Does it work with payment fields?
Yes. Calculation fields feed the payment field automatically — totals computed in the form become the charge amount, validated server-side before Stripe processes the payment.
Can the result trigger conditional logic?
Yes. Use a calculation result in a condition: show a discount message above $500, route high scorers to a different end screen, gate a follow-up question by the calculated value.
Is there a limit on the number of calculations per form?
No hard limit on calculation field count. We do enforce a sensible per-form complexity limit to keep forms responsive — even very complex calculators stay well within it.
Are calculations included in the free plan?
Yes. Calculation fields are available on every plan, including the free tier. No add-on, no per-calculation cost.

Related

Payment forms

Use calculations to drive Stripe payment amounts on order forms, donations, and event tickets.

Learn more →

Online quiz maker

Build scored quizzes with auto-grading powered by calculation fields and conditional outcomes.

Learn more →

Conditional logic

Branch your form based on calculation results. Different outcomes for different scores or totals.

Learn more →

Add a calculation field to your next form

Free on every plan. Visual formula builder. Updates live as respondents type.

Get Started — Free