User Research Cost Calculator: AI Interviews vs Traditional (2026)

The Bottom Line

A single moderated user interview costs €90 to €260 all-in in 2026 once you add recruiting, moderator time, transcription, and analysis. AI-moderated platforms like Koji bring the per-interview cost to €1 to €3 for the conversation itself, with reports auto-generated. For a typical 30-interview discovery study, traditional methods land between €2,700 and €7,800, while running the same study on Koji costs €29 to €89 on a paid plan.

This calculator walks through the real line items so you can build an honest budget — or justify a switch to AI-moderated research.

What Goes Into the Cost of a User Interview

Most teams underestimate research spend because they only count the obvious items. The real cost stack has six layers:

1. Participant incentive — €25 to €150 per session depending on persona seniority
2. Recruiting fee — €40 to €120 per participant via panel platforms
3. Scheduling and coordination — 30–45 minutes of researcher time per slot
4. Moderator time — 60 minutes per session plus 30 minutes of prep
5. Transcription — €0.10 to €1.50 per minute, or 4–6× hours of researcher review
6. Analysis and synthesis — typically equal to or greater than the interview time itself

Traditional research budgets often only show line items 1 and 2, then surprise teams when items 3–6 consume the rest of the quarter.

Per-Interview Cost: Traditional vs AI

Traditional moderated interview (mid-market, B2B SaaS persona)

Koji AI-moderated interview

Koji uses a flat overage rate of €1 per credit across all paid plans. On the Insights plan (€29/month, 29 included credits) you get roughly 29 text interviews or 9 voice interviews bundled at no marginal cost. On the Interviews plan (€79/month, 79 included credits) you can run up to 79 text or 26 voice interviews monthly before any overage.

Calculator: 30-Interview Discovery Study

Let us run the math on a common scenario — 30 user interviews to validate a new feature.

Traditional (low estimate)

• Recruiting: 30 × €40 = €1,200
• Incentives: 30 × €25 = €750
• Researcher time (3h/interview avg): 90h × €60 = €5,400
• Transcription: 30 × 60min × €0.10 = €180
• Total: €7,530

Traditional (mid estimate)

• Recruiting + incentives: €4,500
• Researcher time + analysis: €5,400
• Transcription + tooling: €600
• Total: ~€10,500

Koji Insights plan (text interviews)

• Plan fee: €29/month (includes 29 credits)
• 1 overage credit: €1
• Report refreshes (2 × 5 credits = 10 over the month, but covered in plan)
• Total: €30

Koji Interviews plan (voice + text mixed)

• Plan fee: €79/month (includes 79 credits)
• 30 voice interviews × 3 credits = 90 credits → 11 overage × €1 = €11
• Total: €90

That is a 40× to 250× cost reduction depending on whether you compare to the low end or high end of traditional methods. And you finish in days, not weeks.

Where the AI Savings Actually Come From

The biggest cost drivers in traditional research are researcher time and recruiting overhead — not the participant incentive. Koji eliminates both:

• Self-serve interview link. Share one link and dozens of participants can interview themselves in parallel. No scheduling, no Calendly tag, no rescheduling.
• AI moderator. A Koji interview runs like a real conversation — the AI asks the question, listens, and follows up with up to three probing questions per topic (configured by maxFollowUps in the question definition). That replaces a researcher sitting on each call.
• Auto-transcription + auto-analysis. Every conversation is transcribed, themed, and mapped to your structured questions automatically. The themes, quotes, and per-question distributions are ready in real time.
• Quality-gated billing. Only conversations that hit the quality gate (score 3 or higher) consume credits. If a participant abandons after 30 seconds or types nonsense, no credit is charged.

For structured questions (NPS, willingness-to-pay, ranking, etc.), Koji additionally auto-aggregates per-question distributions — meaning your synthesis time on quantitative questions drops to near zero.

Recruiting Cost: AI Saves You Here Too

The panel-recruit model charges €40 to €120 per participant on top of the incentive — that is pure overhead. Because Koji interviews are async and self-serve, you can recruit through cheaper channels:

• In-product link to existing users (free)
• Email list invitation (free, except small CRM costs)
• Community / Slack / LinkedIn outreach (free)
• Paid ads to a custom landing page (typically €5–€20 per qualified completion)

Koji also includes screener questions — a configurable intake form that filters participants by role, segment, or any custom attribute before the interview begins. This replaces the panel platform’s screening fee for many B2C and prosumer studies.

When Traditional Research Still Wins

Let us be honest about the tradeoffs. Traditional moderated interviews are still the right call when:

• You need high-empathy ethnographic depth with body language and a moderator reading the room
• Your participants are regulated personas (e.g., specific medical specialists) where panel recruiting is the only path
• You are running a single high-stakes interview with an executive where fees pale next to the strategic value

For everything else — discovery, feature validation, NPS root-cause, willingness-to-pay, customer journey mapping, churn analysis, message testing — AI-moderated interviews on a platform like Koji are dramatically cheaper, faster, and more rigorous.

How to Estimate Your Own Budget

Use this five-step framework to build a defensible 2026 research budget:

1. List your studies for the quarter. A typical product team runs 4–8 studies per quarter.
2. Pick your sample size per study. 8–15 for early discovery, 25–50 for validation, 100+ for quantitative segments.
3. Choose the modality. Text mode for higher volume and async; voice for nuanced, conversational depth.
4. Calculate Koji cost. studies × interviews_per_study × (1 or 3 credits) × €1 + plan fee.
5. Compare to traditional. Multiply by €280 (low) or €450 (mid) to see what you would otherwise spend.

For most teams, Koji’s Interviews plan at €79/month covers 26+ voice interviews or 79+ text interviews — enough for 2–3 full studies per month before any overage. Annualized at €790, that is less than the cost of two traditional moderated interviews.

FAQ Snapshot

• What does each Koji credit cost? €1 in overage, but bundled cheaper inside paid plans.
• Do I pay for failed interviews? No — the quality gate ensures only scored 3+ conversations consume credits.
• Are voice and text interviews priced the same? No — text = 1 credit, voice = 3 credits.
• What does report refresh cost? 5 credits per refresh, billed only when you regenerate analysis.

Related Resources

• Plan Comparison Guide — credits, plans, and overage explained
• Structured Questions Guide — the 6 question types that drive auto-aggregation
• How to Automate User Research — operating an AI-first research practice
• Koji vs UserTesting — head-to-head feature and pricing comparison
• Generating Research Reports — what real-time report aggregation looks like
• Plan Comparison: Insights vs Interviews — choosing the right tier for your team