loanTotalCost()
Calculate the total amount repaid over the full loan term (all installments plus financed fees) — essential for “how much will I pay in total?” lines on loan calculators.
Syntax
Every formula in Calcopolis must start with = in the Value field:
= loanTotalCost(amount, interestRate, months, commission, installments)
| Part | Rule |
|---|---|
| Function name | loanTotalCost — camelCase |
interestRate |
Annual rate as decimal (0.05 = 5%) |
| Optional | commission (decimal), installments ("EQUAL" or "DECREASING") |
| Return value | Sum of all payments over the term |
Valid examples
= loanTotalCost(loan_amount, interest_rate/100, term_months)
= roundTo(loanTotalCost(loan_amount, interest_rate/100, term_months, 0.01), 2)
Invalid / unsupported
| Don't write | Why |
|---|---|
Using percent rate directly |
Use interest_rate/100 when the form collects percent |
Parameters
| Argument | Description |
|---|---|
amount |
Loan principal. |
interestRate |
Annual interest as decimal. |
months |
Loan term in months. |
commission |
Up-front fee as decimal of principal. Default 0. |
installments |
"EQUAL" or "DECREASING". Default "EQUAL". |
When to use loanTotalCost()
Use alongside monthly payment for full-picture finance UX:
| Situation | What loanTotalCost() does |
|---|---|
| Total repayment | Principal + interest + fees across the term |
| Compare offers | Same principal, different rates or commissions |
| DECREASING loans | Sums each decreasing installment |
Subtract principal (and commission) manually, or use [loanTotalInterest()](/docs/reference/formulas/loan-total-interest-function/) for interest-only totals.
Practical examples (ecommerce & leads)
1. Mortgage summary block
| Variable | Formula |
|---|---|
monthly_payment |
= roundTo(loanInstallmentAmount(loan_amount, interest_rate/100, term_months), 2) |
total_repaid |
= roundTo(loanTotalCost(loan_amount, interest_rate/100, term_months), 2) |
Show both on Result widgets.
2. Compare with and without origination fee
| Variable | Formula |
|---|---|
total_with_fee |
= loanTotalCost(loan_amount, interest_rate/100, term_months, 0.02) |
total_no_fee |
= loanTotalCost(loan_amount, interest_rate/100, term_months, 0) |
Where to use it
| Location | Supported |
|---|---|
| Result widget Value | Yes — = ... formulas |
| Standalone variable (Variables tab) | Yes |
| Number / other input default Value | Yes, if formula-driven |
| Visibility formula | Yes |
| Custom Text / Table cells | No — use {{ }} templates there, not = functions |
After editing, run Calculate (or enable Run calculation on load in project Options) to refresh results.
Related
- [
loanTotalInterest()](/docs/reference/formulas/loan-total-interest-function/) - [
loanInstallmentAmount()](/docs/reference/formulas/loan-installment-amount-function/) - Understanding Formulas and Variables —
=syntax and variables - Building Your First Calculator — end-to-end quote calculator