/
GDS and TDS are the two ratios a Canadian lender checks first: how much of your gross income goes to housing, and how much goes to housing plus every other debt. Enter your numbers below.
Published: 2026-08-08 · Verified: 2026-08-08 · Author: usecos.app Research & Engineering
Direct answer
Direct answer: GDS is housing costs (mortgage payment, property tax, heating, 50% of condo fees) divided by gross income; TDS adds every other debt payment on top. CMHC's published maximum for insured mortgages is 39% GDS and 44% TDS. A household earning $120,000 with a $2,200 mortgage payment, $400/mo property tax and $150/mo heating sits at 27.5% GDS — well within guideline.
All applicants combined, before tax.
Principal and interest only.
Only 50% counts toward GDS/TDS. Leave at 0 if not a condo.
Car loans, credit cards, student loans, support payments.
GDS Ratio
0.0%
Within guideline
Max guideline: 39%
TDS Ratio
0.0%
Within guideline
Max guideline: 44%
Monthly gross income
$10,000/mo
Annual income ÷ 12
Housing costs (GDS)
$2,750/mo
Payment + tax + heat + 50% condo fees
Housing + other debt (TDS)
$3,150/mo
GDS costs plus other monthly debt
| Scenario | Inputs | Result | Interpretation |
|---|---|---|---|
| $120,000 income, $2,200 payment | $400/mo tax, $150 heat, no condo, $400 other debt | 27.5% GDS / 31.5% TDS | Well within guideline on both ratios. |
| $96,000 income, $1,800 payment, condo | $0 tax, $0 heat, $600 condo fees, $0 other debt | 26.25% GDS / 26.25% TDS | Only 50% of condo fees ($300) count toward the ratio. |
| $85,000 income, $2,300 payment | $350/mo tax, $175 heat, no condo, $650 other debt | 38.7% GDS / 47.7% TDS | GDS is at the limit; TDS is over the 44% guideline — other debt is the problem, not the mortgage. |
GDS = (payment + property tax + heating + 50% condo fees) ÷ gross income
TDS = (GDS costs + other debt payments) ÷ gross income
Both ratios use the same monthly gross income denominator — all applicants' income, combined, before tax. TDS is never lower than GDS, because it includes everything GDS includes plus more.
Methodology: the calculator converts your annual income and property tax to monthly figures, adds heating and 50% of condo fees to the mortgage payment for the GDS numerator, adds other monthly debt for the TDS numerator, then divides each by monthly gross income. It follows CMHC's published GDS/TDS formula.
| Ratio | CMHC maximum | Covers |
|---|---|---|
| GDS | 39% | Mortgage payment, property tax, heating, 50% of condo fees |
| TDS | 44% | Everything in GDS, plus car loans, credit cards, student loans and other debt |
39%/44% is CMHC's published maximum for insured mortgages. Individual lenders can apply stricter internal limits — confirm the number that applies to your file with your lender or broker before relying on this result.
Lenders generally want GDS at or below 39% and TDS at or below 44% — the maximum ratios CMHC publishes for insured mortgages. Lower is safer: a ratio close to the maximum leaves little room for a rate increase, an income drop or an unexpected expense.
GDS (Gross Debt Service) covers housing costs only: mortgage payment, property tax, heating, and 50% of condo fees. TDS (Total Debt Service) adds every other debt payment — car loans, credit cards, student loans, support payments — on top of those same housing costs. TDS is always equal to or higher than GDS.
CMHC's guidance treats half of monthly condominium fees as a housing cost for GDS/TDS purposes, on the basis that a portion typically covers reserve funds and building costs rather than day-to-day carrying cost. Non-condo properties skip this line entirely.
Enter your real monthly heating bill if you know it — from a past bill or the seller's disclosure. If you don't have a figure yet, CMHC directs lenders to use a reasonable estimate based on the property's size, location and heating type; this calculator does not generate that estimate for you.
39%/44% is CMHC's published maximum for insured mortgages. Individual lenders can apply stricter internal limits depending on credit score, mortgage type, and whether the mortgage is insured or conventional. Confirm the specific limit that applies to you with your lender or broker.
Calculations, interest rates, and tax threshold benchmarks displayed across UseCOS tools are updated as of August 2026 based on official publications from the Bank of Canada, Canada Revenue Agency (CRA), OSFI, and provincial regulatory bodies.
UseCOS provides transparent educational estimates and math comparisons for personal planning. Tools do not guarantee lender approval, tax compliance, or specific mortgage terms.
For binding mortgage rate commitments, loan contracts, or official tax filings, please consult a licensed Canadian mortgage broker, CPA, or official lender representative.